Foreword This document Is an updated version of the guidance material first published in 1979 for the information of aircrews intending to operate in North Atlantic MNPS Airspace. It will also be helpful to flight dispatchers. The manual has been produced with the approval and on behalf of the North Atlantic Systems Planning Group. Joint Editors: Lawrie Dunn Head of INT 7 UK National Air Traffic Services Alan Gilbert Regional Technical Director NAT/NAM, IATA Further material for the information of States of Registry and aircraft operating agencies dealing primarily with planning and management aspects of NAT MNPS operations is contained in ICAO Consolidated Guidance Material NAT Region (Sixth Edition, (NAT Doc. 001. T13.5 N), published by the European Office of ICAO. This document is for guidance. Regulatory material relating to North Atlantic aircraft operations is contained in relevant ICAO Annexes. PANS/RAC (Doc. 4444), Regional Supplementary Procedures (Doc. 7030) State AIPs and current NOTAMs which should be read in conjunction with the Guidance Material contained in this document. MINIMUM NAVIGATION PERFORMANCE SPECIFICATION AIRSPACE (MNPSA) The vertical dimension of the MNPSA is between FL275 and FL400. The lateral dimensions include the following Control Areas (CTAs): REYKJAVIK (to the North Pole) SHANWICK AND GANDER OCEANIC SANTA MARIA OCEANIC North of 27ºN NEW YORK OCEANlC excluding the area west of 60ºW and south of 38º30'N. Some idea of these dimensions can be obtained from the map on the cover and the map in Chapter 2. However, for the specific dimensions, refer to Doc. 7030 Reg. Supp. Procedures NAT/ RAC para 2.2.1. Pilots MUST NOT fly across the North Atlantic within Minimum Navigation Performance Specification Airspace unless the flight has been certified by the State of Registry or the State of the Operator. In developing this Sixth Edition, the loose Pink Sheet of the previous edition has been incorporated in Chapter 14. Glossary of Terms AFTN Aeronautical Fixed Telecommunication Network AIP Aeronautical information Publication ATC Air Traffic Control ATS Air Traffic Services CDU Control Display Unit CMA Central Monitoring Agency CTA Control Area DME Distance Measuring Equipment FIR Flight Information Region FL Flight Level FMS Flight Management System GNE Gross Navigation Error HSI Horizontal Situation Indicator IFR Instrument Flight Rules IGA International General Aviation INS Inertial Navigation System IRS Inertial Reference System ISS Inertial Sensor System LRNS Long Range Navigation System MNPS Minimum Navigation Performance Specification MNPSA Minimum Navigation Performance Specification Airspace MTT Minimum Time Track NAR North American Routes NAT North Atlantic NAT SPG North Atlantic Systems Planning Group OAC Oceanic Area Control Centre OCA Oceanic Control Area ONS OMEGA Navigation System OSS OMEGA Sensor System OTS Organized Track System PRM Preferred Route Message PTS Polar Track Structure SID Standard Instrument Departure SOTA Shannon Oceanic Transition Area SSR Secondary Surveillance Radar SST Supersonic Transport CONTENTS Chapter 1 THE ORGANISED TRACK SYSTEM (OTS) Appendix: Examples of Day-time Westbound and Night-time Eastbound Track Messages and associated Track Systems (Figures 1 and 2) 2 THE POLAR TRACK STRUCTURE (PTS) (Figure 3) 3 OTHER ROUTES AND ROUTE STRUCTURES WITHIN OR ADJACENT TO NAT MNPS AIRSPACE (Figure 4) 4 FLIGHT PLANNING PROCEDURES 5 OCEANIC ATC CLEARANCES 6 AIR/GROUND COMMUNICATIONS AND POSITION REPORTING PROCEDURES 7 APPLICATION OF MACH NUMBER TECHNIQUE. 8 MISCELLANEOUS PROCEDURES 9 AIRCRAFT MINIMUM NAVIGATION CAPABILITY 10 SPECIAL PROCEDURES FOR IN-FLIGHT CONTINGENCIES 11 MNPS CROSS-CHECK PROCEDURES 12 A CHECK LIST FOR PILOTS NOT FAMILIAR WITH OPERATIONS IN NAT MNPS AIRSPACE 13 GUARDING AGAINST COMPLACENCY 14 THE PREVENTION OF DEVIATIONS FROM TRACK AS A RESULT OF WAYPOINT INSERTION ERRORS Figure 1 Example of Day-time Westbound Organised Track System (OTS) Figure 2 Example of Night-time Eastbound Organised Track System (OTS) Figure 3 Polar Track Structure (PTS) Figure 4 Other routes and route structures within and above NAT MNPS Airspace Attachments 1 Guidance for Aircraft Dispatchers 2 Sample of Error Investigation Form Chapter 1 The Organised Track System GENERAL As a result of passenger demands, time zone differences and airport noise restrictions, much of the North Atlantic air traffic contributes to one of two flows; a westbound flow departing Europe in the morning, and an eastbound flow departing North America in the evening. The effect of these flows is to concentrate most of the traffic unidirectionally, peak westbound traffic occurring between 1130 UTC and 1900 UTC, peak eastbound traffic between 0100 UTC and 0800UTC, at 30º west. Because of the constraints of large horizontal separation criteria and a limited economical height band (FL310-390) the airspace is very congested at peak hours. In order to provide the best service to the bulk of the traffic, a system of organised tracks is constructed every 12 hours to accommodate as many aircraft as possible on or close to their minimum time paths. Over the high seas the NAT Region is Class A airspace at and above FL55. in which the Instrument Flight Rules (IFR) apply at all times. However airspace utilisation is improved by the strategic use of so-called opposite direction flight levels, e.g. FL350, 390 eastbound and FL330, 370 westbound during peak flow periods. The application of Mach Number Technique permits further improvement of utilisation along track and helps to facilitate en route step-climbs. (See Chapter 7.) The variability of the weather system would in any case necessitate reconstruction of the organised track system at frequent intervals. Furthermore, because of the energetic nature of weather systems, including jet streams, eastbound and westbound minimum time tracks are seldom identical. The creation of a different organised track system is therefore necessary every 12 hours. CONSTRUCTION OF THE ORGANISED TRACK SYSTEM (OTS) After determination of basic minimum time tracks, with due consideration of airlines preferred routes (see Chapter 4) and taking into account airspace restrictions such as Danger Areas and military airspace reservations, the organised track system is constructed by the appropriate Oceanic Area Control Centre (OAC), the night-time OTS by Gander OAC and the day-time by Shanwick OAC (Prestwick), each taking into account tracks which New York, Reykjavik, Bodo and/or Santa Maria OACs may require in their Oceanic Control Areas (OCAs). In each case OAC planners consult each other and co-ordinate with adjacent OACs and domestic ATC agencies to ensure that the proposed system is viable. They also take into account the anticipated requirements of opposite direction traffic and ensure that sufficient track/flight level profiles are provided to satisfy anticipated traffic demand. The impact on domestic route structures and the serviceability of transition area radars and navaids are checked before the system is finalised. When the expected traffic level justifies it, tracks are established to cater for the EUR/CAR axis. Extra care is required when planning on these routes as they differ slightly from the 'core tracks' in that they may cross, and in some cases may not extend from coast out to coast in (necessitating random routing to join or leave). Similarly, tracks may commence at 30ºW north of 61ºN to cater for NAT traffic routeing via Reykjavik OCA and northern Canada. The agreed organised track system is then promulgated as the NAT Track Message via the AFTN to all interested addressees. A typical time of publication of the daytime OTS is 0000 UTC and of the night-time OTS is 1200 UTC. Examples of both systems showing track and flight level availability are in the Appendix to this Chapter. THE NAT TRACK MESSAGE This message gives full details of the co-ordinates of the organised tracks as well as the flight levels that are expected to be in use on each track. In most cases there are also details of domestic entry and exit routeings associated with individual tracks. In the day-time system the track most northerly, at its point of origin, is designated Track 'A' (Alpha) and the next most northerly Track 'B' (Bravo) etc. In the night-time system the most southerly track, at its point of origin, is designated Track 'Z' (Zulu) and the next most southerly 'Y' etc. The hours of validity of the two Organised Track Systems (OTS) are normally as follows: Day-time OTS 1130 UTC - 1900 UTC at 30º W Night-time OTS 0100 UTC - 0800 UTC at 30º W Changes to these times can be negotiated between Gander and Shanwick OACs and the hours of validity are specified in the NAT Track Message for each system, but extensions can be agreed when required. Correct interpretation of the track message by airline dispatchers and aircrews is essential to both economy of operation and in minimising the possibility of misunderstanding leading to the use of incorrect track co-ordinates (see Chapter 5). Oceanic airspace outside the published OTS is available, subject to separation criteria and NOTAM restrictions. It is usually possible for ATC to clear aircraft to join or leave an outer track of the OTS without difficulty. If an operator wishes to file partly or wholly outside the OTS. knowledge of separation criteria, the forecast upper wind situation and correct interpretation of the NAT Track Message will assist in judging the feasibility of the planned route. When the anticipated volume of traffic does not warrant publication of all available flight levels on a particular track. ATC will publish only those levels required to meet traffic demand. The fact that a specific flight level is not published for a particular track does not necessarily mean that it cannot be made available if requested. On occasions tracks on two successive systems may appear to have the same coordinates, but special care should be taken to ensure that this is really the case for the whole track. The same applies to the associated landfall/termination points and domestic routeings. OTS CHANGEOVER PERIODS To ensure a smooth transition from night to day track systems and vice-versa, a period of several hours is interposed between the termination of one system and the commencement of the next. Eastbound traffic crossing 30W between 0930UTC and 1029 UTC in MNPS airspace should file random flight plans at Eastbound FLs (290, 330, 370). Where the flight will conflict with the day-time (Westbound) OTS the route should follow the day-time structure from 30W. However such traffic may plan to join the outer track of the day-time structure at any point. Westbound traffic crossing 30W between 2300 UTC and 2359 UTC in MNPS airspace should file random flight plans at Westbound Fts (280, 310, 350, 390). Where the flight will conflict with the night-time (Eastbound) OTS the route should follow the night-time structure from 30W. However such traffic may plan to join the outer track of the night-time structure at any point. Flights against the Peak Flow Eastbound traffic crossing 30W at 1030 UTC or later and Westbound traffic crossing 30W at 0000 UTC or later should plan to avoid the OTS. Appendix Examples of Day-time Westbound and Night-time Eastbound Track Messages and Associated Track Systems. EXAMPLE OF WESTBOUND NAT TRACK MESSAGE (NAT-I/2 TRACKS FLS 310/370 INCLUSIVE AUGUST 14/1130 UTC TO AUGUST 14/1900 UTC PART ONE OF TWO PARTS- A 57/10 59/20 59/30 58/40 56/50 SCROD VALIE EAST LVLS NIL, WEST LVLS 310 330 350 370 EUR RTS WEST 2 NAR NA212 NA214 NA218- B 56/10 58/20 58/30 57/40 55/50 OYSTR STEAM EAST LVLS NIL WEST LVLS 310 330 350 370 EUR RTS WEST 2 NAR NA202 NA204 NA206- C 55/10 57/20 57/30 56/40 54/50 CARPE REDBY EAST LVLS NIL WEST LVLS 310 330 350 370 EUR RTS WEST 2 NAR NA186 NA190 NA194- D MASIT 56/20 56/30 55/40 53/50 YAY EAST LVLS NIL WEST LVLS 310 330 350 370 EUR RTS WEST 2 VIA DEVOL NAR NA168 NA170 NA174- E 54/15 55/20 55/30 54/40 52/50 DOTTY EAST LVLS NIL WEST LVLS 310 330 350 370 EUR RTS WEST 2 VIA BURAK NAR NA144 NA150- END OF PART ONE OF TWO PARTS) (NAT-2/2 TRACKS FLS 310/370 INCLUSIVE AUGUST 14/1130 UTC TO AUGUST 14/1900UTC PART TWO OF TWO PARTS- F 53/15 54/20 54/30 53/40 51/50 CYMON EAST LVLS NIL WEST LVLS 310 330 350 370 EUR RTS WEST 2 VIA DOLIP NAR NA122 NA128- G 52/15 53/20 53/30 52/40 50/50 YQX EAST LVLS NIL WEST LVLS 310 330 350 370 EUR RTS WEST 2 VIA GIPER NAR NA100 NA108- H 51/15 52/20 52/30 51/40 49/50 VIXUN EAST LVLS NIL WEST LVLS 310 330 350 370 EUR RTS WEST 2 VIA KENUK NAR NA82 NA86- REMARKS 1. OPERATORS ARE REMINDED THAT SPECIFIC MNPS CERTIFICATION TO FLY WITHIN MNPS AIRSPACE FL275 TO FL400 IS REQUIRED END OF PART TWO OF TWO PARTS) Fig 1 Example of Day-time Westbound Organised Track System EXAMPLE OF EASTBOUND NAT TRACK MESSAGE (NAT 1/2 TRACKS FLS 310/390 INCLUSIVE JULY 16/0l00UTC TO JULY 16/0800UTC PART ONE OF TWO PARTS T YGX 50/50 52/40 54/30 54/20 54/15 BABAN EAST LVLS 330 350 370 390 WEST LVLS NIL EUR RTS WEST NIL NAR NA63 NA69- U VIXUN 49/50 51/40 53/30 53/20 53/15 BURAK EAST LVLS 310 330 350 370 390 WEST LVLS NIL EUR RTS WEST NIL NAR NA53 NA 57- V YYT 48/50 50/40 52/30 52/20 52/15 DOLIP EAST LVLS 310 330 350 370 390 WEST LVLS NIL EUR RTS WEST NIL NAR NA43 NA45- W COLOR 47/50 49/40 51/30 51/20 51/15 GIPER EAST LVLS 330 350 370 390 WEST LVLS NIL EUR RTS WEST NIL NAR NA31 NA33- X BANCS 46/50 48/40 50/30 50/20 50/15 KENUK EAST LVLS 330 350 370 390 WEST LVLS NIL EUR RTS WEST NIL NAR NA21 NA23- END OF PART ONE OF TWO PARTS) (NAT-2/2 TRACKS FLS 310/390 INCLUSIVE JULY 16/0100UTC TO JULY 16/0800UTC PART TWO OF TWO PARTS Y POGGO 43/60 44/50 44/40 44/30 44/20 4330/13 STG EAST LVLS 330 370 WEST LVLS NIL EUR RTS WEST NIL NAR NIL- Z 18/60 24/55 30/50 39/40 44/30 47/20 48/15 48/08 QPR EAST LVLS 350 390 WEST LVLS NIL EUR RTS WEST NIL NAR NIL- REMARKS 1. OPERATORS ARE REMINDED THAT SPECIFIC MNPS CERTIFICATION TO OPERATE WITHIN MNPS AIRSPACE FL275 TO FL400, IS REQUIRED FROM THEIR STATE AVIATION AUTHORITY. END OF PART TWO OF TWO PARTS) Fig 2. Example of Night-time Eastbound Organised Track System. Chapter 2 The Polar Track Structure (PTS) GENERAL A Polar Track Structure (PTS), consisting of 10 fixed tracks in Reykjavik CTA and 5 fixed tracks through Bodo OCA has been established. The PTS tracks through Bodo OCA constitute a continuation of relevant PTS tracks in Reykjavik CTA (see Fig 3). Although not mandatory, flights planning to operate on the Europe-Alaska axis at FL310-390 inclusive are recommended to submit flight plans in accordance with one of the promulgated PTS tracks. ABBREVIATED CLEARANCES An abbreviated clearance may be used when clearing an aircraft to follow one of the polar tracks throughout its flight within the Reykjavik CTA and/or the Bodo OCA. When an abbreviated clearance is issued it shall include: the cleared track specified by the track code; the cleared flight level(s); and the cleared Mach Number. (if required) On receipt of an abbreviated clearance the pilot shall read back the contents of the clearance message and in addition the full details of the track specified by the track code. ABBREVIATED POSITION REPORTS When operating on the PTS within the Reykjavik CTA and/or Bodo OCA position reports may be abbreviated by replacing the normal latitude co-ordinate with the word 'Polar' followed by the track code. eg: Position Japanair 422 Polar Romeo 20W/1620, estimating Polar Romeo 40W/1718 Flight Level 330, next Polar Romeo 69W. Unless otherwise required by air traffic services a position report shall be made at the significant points listed in the appropriate AIP for the relevant PTS track. ADDITIONAL INFORMATION ON THE PTS Flight planning procedures for the PTS are covered in Chapter 4 of this document. Further information on PTS procedures, track co-ordinates etc, is contained in AIP Iceland/Norway and/or Icelandic/Norwegian NOTAMs. Fig. 3 Polar Track Structure (PTS) Chapter 3 Other Routes and Route Structures Within or Adjacent to NAT MNPS Airspace. GENERAL The Organised Track System and the Polar Track Structure are the most significant route structures within the NAT MNPS Airspace. Other route structures within and adjacent to the MNPS Airspace are detailed below. OTHER ROUTES WITHIN NAT MNPS AIRSPACE Other routes within NAT MNPS airspace which are illustrated in Fig 4 are as follows: (1) A699 and A700 in the western part of the New York OCA; (2) special routes between North Eastern Canada and Europe via Greenland and Iceland, between Ireland/United Kingdom and Spain, and between the Azores and the Portuguese mainland for aircraft equipped with normal short- range navigation equipment (VOR, DME, ADF) and at least one approved fully operational long-range navigation system; (3) special routes of short stage lengths where aircraft equipped with normal short-range navigation equipment can meet the MNPS track-keeping criteria (G3 and G11). (4) routes between Northern Europe and Spain/Canaries/Lisbon FIR. (T9, T14 and T16) ROUTE STRUCTURES ADJACENT TO NAT MNPS AIRSPACE SST Route Structure The SST Route structure (also illustrated in Fig 4) comprises three fixed tracks: SM, SN and SO. SST flights on these tracks normally operate well above MNPS airspace (FL 500 +), the exceptions being in the event of a delayed supersonic acceleration or an emergency descent. Standard separation is applied in the first case and emergency descent contingency procedures take into account the possible existence of OTS traffic operating below the SST tracks. Irish/UK Domestic Route Structures The Irish and the UK AIPs contain tables for westbound and eastbound NAT traffic which detail the routes to be used based on departure/destination and entry/exit point for oceanic airspace. North American Routes (NARs) The North American Routes consist of a numbered series of predetermined routes which form a link between oceanic track exit and entry points and the North American domestic airspace route structure in both directions. Specific route numbers related to each track exit/entry point are published in the North Atlantic Track Message under the heading NAR. For example NAR NA 20, NA 24 under track B means that after the exit point of Track B flights may flight plan on NA 20 or NA 24 depending on their destination. Full details of the routeings, procedures etc can be found in the United States International Flight Information Manual and the Canadian Flight Supplement. Canadian Domestic Track Systems. Within Canada there are three track systems; the Northern Track System and the Southern Control Area tracks which link NAT traffic operating between Europe and North America and an Arctic Route System which interfaces with the Polar Track Structure for traffic between Europe and Alaska. The track procedures and details are published in the Canadian AIP and Designated Airspace Handbook. Routes between North America and the Caribbean area In the New York Oceanic Control Area to the west of 60º west there is an extensive network of routes linking points in the United States and Canada with Bermuda, the Bahamas and the Caribbean area. Details of these routes and associated procedures are contained in the United States AIPs. Shannon Oceanic Transition Area (SOTA) Part of the Shanwick OCA is designated as the Shannon Oceanic Transition Area (SOTA). MNPSA requirements are still applicable from FL275 to FL400. SOTA has the same vertical extent as the Shanwick OCA, and is bounded by lines joining successively the following points: N5100 W01500 - N5100 W00800 - N4830 W00800 - N4900 W01500 - N5100 W01500. Air Traffic Service is provided by Shannon Air Traffic Control Centre, using the call sign SHANNON. Full details of the service provided and the procedures used are contained in AIP Ireland. Fig. 4 Other Routes and Structures Within and Above NATS MNPS Airspace Chapter 4. Flight Planning Procedures PREFERRED ROUTE MESSAGES (PRM) To enable oceanic planners to take into consideration operators' preferred routes in the construction of the OTS, all NAT operators (both scheduled and non-scheduled) should provide information by AFTN message to the appropriate OACs regarding their proposed flights and optimum tracks during the peak traffic periods. Such information should be provided, in the correct format, as far in advance as possible, but not later than 1900UTC for the day-time OTS and 1000UTC for the night-time OTS. Addresses and formats are published in the relevant AIPs/NOTAMS. ATC FLIGHT PLANS General Requirements Operators are encouraged to flight plan as follows: in accordance with the OTS; or a route to join or leave an outer track of the OTS; or a random route to remain clear of the OTS. Nothing in the paragraph above prevents operators from flight planning across the OTS. However they should be aware that whilst ATC will make every effort to clear random traffic across the OTS at published levels, re-routes or changes in flight level are likely to be necessary during most of the OTS traffic periods. Flights planning to operate wholly or partially outside the NAT Organised Track System (OTS) should flight plan level(s) appropriate to the direction of flight except that during the westbound OTS (valid from 1130 UTC to 1900 UTC at 30º West) westbound aircraft may flight plan FL 330 and during the eastbound OTS (valid from 0100 UTC to 0800 UTC at 30º West) eastbound aircraft may flight plan FL 350. Outside the hours of validity of the OTS and the changeover periods (see Chapter 1) operators are encouraged to flight plan a random route at flight levels appropriate to the direction of flight. If necessary and in all cases of doubt, dispatchers should seek the advice of the appropriate Oceanic Centre on the best procedure to adopt. It is essential that care is taken when feeding track information into a computer and the Information should be cross- checked before it is given to the operating crew. Where applicable, the crew shall be given both the organised track message and relevant amendments to it. The correct completion of the flight plan is extremely important as errors can lead to delay in data processing and subsequent clearance of the flights concerned. Flight plans for flights departing from points in other Regions and entering the NAT Region without Intermediate stops should be submitted as far in advance of departure as possible. All generally eastbound and westbound flights should normally flight plan so that specified ten degrees of longitude (20ºW, 30ºW, 40ºW etc) are crossed at whole degrees of latitude; and generally northbound and southbound flights should normally flight plan so that specified parallels of latitude spaced at five degree intervals (65ºN, 60ºN, 55ºN etc) are crossed at whole degrees of longitude. All flights should plan to operate on great circle tracks joining successive significant points. For all flights intending to operate within NAT MNPS airspace for any portion of their flight the letter X should be inserted after the letter S in Item 10 of the flight plan indicating that the flight is certified as being in compliance with the MNPS. For turbojet aircraft the Mach Number planned to be used for each portion of the night in the NAT Region should be specified in Item 15 of the flight plan. Item 15 of the flight plan should reflect the proposed speeds in the following sequence: Climbing speed in knots; Significant point at which cruising speed will commence and cruising speed in knots: Oceanic entry point and cruising MACH number; Oceanic landfall and cruising speed in knots. FLIGHT PLANNING REQUIREMENTS ON SPECIFIC ROUTES. Flights Planning on the Organised Track System If (and only if) the flight is planned to operate along the whole length of one of the organised tracks as detailed in the North Atlantic Track Message, the intended organised track should be defined in Item 15 of the flight plan using the abbreviation 'NAT' followed by the code letter assigned to the track. Flights wishing to join or leave an organised track at some intermediate point are considered to be random route aircraft and full route details must be specified in the flight plan. The track letter should not be used to abbreviate any portion of the route in these circumstances. The planned Mach Number and flight level at the commencement point of the organised track should be specified at either the last domestic reporting point prior to ocean entry or the organised track commencement point. Each point at which a change of Mach Number or flight level is requested must be specified as geographical co- ordinates in latitude and longitude or as a waypoint name. For flights operating along the whole length of one of the organised tracks, estimates are only required for the commencement point of the track. Flights planning on random route segments at/or South of 70ºN The requested Mach Number and flight level should be specified at either the last domestic reporting point prior to ocean entry or the oceanic control area boundary. The route of the flight should be specified in terms of the following significant points: (1) the last domestic reporting point prior to oceanic entry point; (2) the oceanic control area boundary entry point; (3) significant points formed from the intersection of half or whole degrees of latitude with meridians spaced at intervals of ten degrees of longitude from the prime meridian to 70ºW; (4) the oceanic control area boundary exit point; and (5) the first domestic reporting point after ocean exit. Each point at which a change of Mach Number or flight level is requested must be specified and followed in each case by the next significant point. Estimates are required for all significant points listed in (1), (3) and (5) above. Estimates may also be required for points listed in (2) and (4). See Note below. NOTE: FIR boundary estimates are only required in flight plans for flights operating through Shanwick, Santa Maria and New York FIRs as follows: Shanwick RR: All random flight plans must contain FIR boundary estimates for the eastern, northern and southern boundaries of the Shanwick Oceanic Control Area and 30º West boundary estimates for eastbound random flights in transit through the Gander, Shanwick FIRs. New York/Santa Maria FIRs: All flight plans must contain New York/Santa Maria FIR boundary estimates. Flights planning on a generally East or Westbound direction on random route segments North of 70ºN Flight planning requirements for flights in the above category are identical to those listed for flights on random route segments at/or south of 70ºN except that the route should be specified in terms of significant points formed by the intersection of parallels of latitude expressed in degrees and minutes with meridians normally spaced at intervals of 20º from the prime meridian to 60ºW. Flights planning on random routes in a generally North or Southbound direction Flight planning requirements for flights in the above category are identical to those listed for flights operating on random route segments at/or south of 70ºN except that the route should be specified in terms of significant points formed by the intersection of whole degrees of longitude with specified parallels of latitude which are spaced at 5º intervals from 20ºN to 90ºN. Flights planning on the Polar Track Structure (PTS) If (and only if) the flight is planned to operate along the whole length of one of the Polar tracks, the intended track should be defined in Item 15 of the flight plan using the abbreviation 'PTS' followed by the track code. Flights wishing to join or leave a polar track at some Intermediate Point are considered to be random route aircraft and full track details must be specified in the flight plan. The track code must not be used to abbreviate any portion of the route in these circumstances. Estimated times over significant points shall be specified in Item 18 of the flight plan. The requested Mach Number and flight level should be specified at the commencement point of the PTS or at the NAT Oceanic boundary. Each point at which a Mach Number or flight level change is requested must be specified as geographical co- ordinates in latitude and longitude followed in each case by the abbreviation 'PTS' and the track code. Flights Planning to Operate Without HP Communications The carriage of HF communications is mandatory for flight in the Shanwick OCA. Aircraft with only functioning VHF communications equipment should plan their route outside the Shanwick OCA and ensure that they remain within VHF coverage of appropriate ground stations throughout the flight. Theoretical VHF coverage charts are included in NAT DOC 001.T13.5N Details of communication requirements are published in State AIPs. Chapter 5 Oceanic ATC Clearances GENERAL Pilots should request oceanic clearances as early as possible from the ATC unit responsible for the first oceanic area within which they wish to operate following the procedures and the time-frame laid down in appropriate AIPs. Such clearances, although in most cases obtained some time before reaching the oceanic boundary/entry point, are applicable only from that boundary/entry point. Methods of obtaining oceanic clearances include: use of VHF clearance delivery frequencies when in coverage; use of HF to the OAC through the appropriate aeradio station (if possible at least 40 min before boundary/entry estimate); request via domestic or other ATC agencies; by datalink which is being introduced at some centres. At some airports situated close to oceanic boundaries, the oceanic clearance can be obtained before departure (eg Prestwick, Shannon, Glasgow, Dublin, Belfast, Gander, Goose Bay). After obtaining and reading back the clearance, the pilot should monitor the forward estimate for oceanic entry and if this changes by 3 minutes or more should pass a revised estimate to ATC. As planned longitudinal spacing by these OACs is based solely on boundary estimates, failure to adhere to this ETA amendment procedure may result in a reclearance to a less economical track/flight level for the complete crossing. If the oceanic clearance which the pilot is given in flight differs from the route originally requested and/or the oceanic flight level differs from the current flight level, it then becomes his responsibility to obtain the necessary domestic re- clearance to ensure that he is in compliance with his oceanic clearance when he enters oceanic airspace. There are three elements to an oceanic clearance: route, mach number and flight level. These elements serve to provide the three basic elements of separation: lateral, longitudinal and vertical. Most oceanic clearances issued to individual aircraft are at a specific flight level and cruise Mach number. No level or Mach Number changes should be made without prior ATC clearance. CONTENTS OF CLEARANCES An abbreviated clearance is only issued by Air Traffic Services when clearing an aircraft to fly along the whole length of an organised track or along a polar track within Reykjavik CTA and/or Bodo OCA. When an abbreviated clearance is issued it includes: cleared track specified by Track and code letter or Polar Track and code; cleared flight level(s); cleared Mach Number; and if the aircraft is designated to report Met information en route, the phrase 'SEND MET REPORTS'. Procedures exist for abbreviated read back of westbound clearances issued by Shanwick on VHF. If the pilot is cleared on the original track as requested and the details of that track are confirmed by listening to the Shanwick Track Broadcast Frequency, the read back of the routeing element of the clearance may refer only to the track code letter. Otherwise, the pilot MUST read back the contents of the clearance message and full details of the track specified. If in any doubt, the pilot should request a detailed description of the route from the ATC OCEANIC CLEARANCES FOR FLIGHTS INTENDING TO OPERATE WITHIN THE NAT REGION AND SUBSEQUENTLY ENTER THE EUR OR NAM REGIONS Oceanic clearances issued to most flights in the above category are strategic clearances intended to provide a safe separation for each flight from oceanic entry to track termination point. Should a pilot receive a clearance on a track other than originally flight planned, special caution should be exercised to ensure that the co-ordinates of the assigned track and the associated landfall and domestic routeings are fully understood and correctly inserted into the automated navigation system with appropriate cross checks. In all cases when an en-route reclearance is requested by a pilot he should ensure that the revised ATC clearance includes the new routeings from the exit from oceanic airspace to the first landfall point or coastal fix. If at the time of being given a clearance or reclearance, the pilot has any doubt, he/she should check the details with the ATC unit issuing the clearance/reclearance. OCEANIC CLEARANCES FOR RANDOM FLIGHTS INTENDING TO OPERATE WITHIN THE NAT REGION AND SUBSEQUENTLY ENTER REGIONS OTHER THAN NAM OR EUR Oceanic clearances issued to flights in this category are similar to domestic ATC clearances in that clearances are to destination on the assumption that co-ordination will be effected ahead of the aircraft's passage. In this case the flight profile may be changed en-route, prior to hand over from one centre to another, dependent on traffic conditions in the adjacent area. ERRORS ASSOCIATED WITH OCEANIC CLEARANCES Navigation errors associated with oceanic clearances fall into various categories of which the most important are ATC System Loop and Waypoint Insertion errors. ATC System Loop errors By definition an ATC system loop error is any error caused by a misunderstanding between the- pilot and the controller regarding the assigned flight level, Mach Number or route to be followed. Such errors can arise by incorrect interpretation of the NAT Track Message by dispatchers, errors in co-ordination between ATC centres or misinterpretation of oceanic clearances or reclearances by the pilots. Errors of this nature which are detected by ATC from forward estimates will normally be corrected. However timely ATC intervention cannot always be guaranteed, especially as it may depend on HF communications. Waypoint insertion errors Experience has shown that many of the track keeping errors which occur result from failure to observe the principles of checking waypoints to be inserted against the ATC assigned track and of careful loading and cross-checking of on- board navigation systems. More detailed guidance on this subject is contained in Chapter 11 of this document. Many of the navigation error occurrences detected by ATC oceanic exit radars are the product of one or both of these causes. It is therefore important that pilots double check each element of the oceanic clearance on receipt, and at each waypoint since failure to do so may result in inadvertent deviation from assigned track. Chapter 6 Air/Ground Communications and Position Reporting Procedures HF COMMUNICATIONS Most NAT air/ground communications are conducted on single side-band HF frequencies. Pilots communicate with OACs via aeradio stations manned by communicators who have no executive ATC authority. Messages are relayed usually by radio-teletype from the ground station to the relevant OAC for action. Aeradio stations and OACs are not necessarily colocated, for example in the case of Shanwick operations, the OAC is located at Prestwick in Scotland, the associated aeradio station at Ballygirreen in the Republic of Ireland. The allocation of the families of SSB frequencies (A, B, C, D, E and F) is by State of Registry of the aircraft and the route to be flown. AIPs list the families to be used and additionally, the aeradio stations may advise individual aircraft of the frequencies to be used after initial contact. VHF COMMUNICATIONS The carriage of HF communications is mandatory for flight in the Shanwick OCA. Aircraft with only functioning VHF communications equipment should plan their route outside the Shanwick OCA and ensure that they remain within VHF coverage of appropriate ground stations throughout the flight. Theoretical VHF coverage charts are included in NAT DOC 001.T13.5N. Details of communication requirements are published in State AIPs. TIME AND PLACE OF POSITION REPORTS Unless otherwise required by Air Traffic Services, position reports from flights on routes which are not defined by designated reporting points should be made at the significant points listed in the flight plan. Air Traffic Services may require any flight operating in a North/South direction to report its position at any intermediate parallel of latitude when deemed necessary. In requiring aircraft to report their position at intermediate points ATS are guided by the requirement to have positional information at approximately hourly intervals and also by the need to cater for varying types of aircraft and varying traffic and MET conditions. CONTENTS OF POSITION REPORTS For flying outside the Polar Track Structure and domestic ATS route network, position should be expressed in terms of latitude and longitude except when flying over named reporting points. For flights whose tracks are predominantly east to west, latitude should be expressed in degrees and minutes, longitude in degrees only. For Flights whose tracks are predominantly north or south, latitude should be expressed in degrees only, longitude in degrees and minutes. All times should be expressed in four digits giving both the hour and the minutes UTC when making position reports in the NAT region. STANDARD MESSAGE TYPES Standard air/ground message types and formats are used within the NAT Region and are published in state AIPs and Atlantic Orientation charts. To enable the ground stations to process messages In the shortest possible time, pilots should observe the following rules: (a) use the correct type of message applicable to the data transmitted; (b) state the message type on the contact call to the ground station or at the start of the message; (c) adhere strictly to the sequence of information for the type of message; (d) all times in each of the messages should be expressed in hours and minutes. The message types are shown below with examples: POSITION Example: Position, SWISSAIR 100, 56N 010W 1235, FL330, Estimate 56N 020W 1310, Next 56N 030W REQUEST CLEARANCE Example: Request clearance AMERICAN 123, 56N 020W 1245, FL 330, Estimate 56N 030W 1320, Next 56N 040W Request FL 350. or if a position report is not required Request Clearance SPEEDBIRD 212, Request FL 370. REVISED ESTIMATE Example: Revised Estimate SPEEDBIRD 212, 57N 040W; 0325. MISCELLANEOUS Plain language - format free. ADDRESSING OF POSITION REPORTS Position reports made by aircraft operating within an oceanic control area at a distance of 60 nm or less from the common boundary with an adjacent oceanic control area, including aircraft operating on tracks through successive points on each boundary, should also be made to the area control centre serving the adjacent control area. (In practice this only requires an addition to the address eg 'Shanwick copy Santa Maria'.) METEOROLOGICAL REPORTS From among the aircraft intending to operate on the organised track system, OACs designate those which will be required to report routine meteorological observations at, and midway between, each prescribed reporting point. The designation is made by the OAC when issuing the oceanic clearance using the phrase 'SEND MET REPORTS', and is normally made so as to designate one aircraft per track at approximately hourly intervals, unless otherwise requested by the associated MET Office. Pilots flying tracks partly or wholly off the OTS should include routine Met Observations with every prescribed report. The midpoint observation should be recorded then transmitted at the next designated reporting point. SELCAL When using HF communications pilots should maintain a listening watch on the assigned frequency. This a not necessary if SELCAL is fitted and used correctly. Correct use includes: (1) the provision of the SELCAL code in Flight Plan; (2) the issue of a correction to the SELCAL code if subsequently altered due to a change of aircraft; (3) a check on the operation of the SELCAL equipment at or prior to entry into Oceanic airspace with the appropriate aeradio station. (This SELCAL check must be completed prior to commencing SELCAL watch.); and (4) maintenance of a SELCAL watch. TWELVE TONE SELCAL Flight management staffs and crews of aircraft equipped with 12-tone SELCAL equipment should be made aware that SELCAL code assignment is predicated on geographical area of operation. If the aircraft is later flown in geographical areas other than as originally specified by the aircraft operator, the aircraft may encounter a duplicate SELCAL code situation. Whenever an aircraft is to be flown routinely beyond the area of normal operations or is changed to a new geographic operating area, the aircraft operator should contact the SELCAL Registrar and request a SELCAL code appropriate for use in the new area. When acquiring a previously owned aircraft equipped with SELCAL, many aircraft operators mistakenly assume that the SELCAL code automatically transfers to the purchaser or lessee. This is not true. As soon as practical, it is the responsibility of the purchaser or lessee to obtain a SELCAL code from the Registrar, or, if allocated a block of codes for a fleet of aircraft to assign a new code from within the block of allocated codes. In the latter instance, if 12-tone equipment is involved, the Registrar should be consulted if there is any question as to geographical area of operation and possible code duplication. The registrar can be contacted via the AFTN address KDCAXAAG ATTN. OPS DEPT. (forward to SELCAL Registrar) in the first line of the text. GENERAL PURPOSE VHF COMMUNICATIONS (GP/VHF) Aeradio stations are also responsible for the operation of GP/VHF outlets. These are especially valuable in the vicinity of Iceland, Faeroes and Greenland, VHF not being as susceptible to sunspot activity as HF. (One of these outlets is situated at Prinz Christiansund on the southern tip of Greenland and is remotely controlled from Gander Aeradio station.) When using these frequencies in fringe cover areas however, care should be taken to maintain a SELCAL watch on HF thus ensuring that if VHF contact is lost the aeradio station is still able to contact the aircraft. It is important for the pilot to appreciate that when using GP/VHF he is communicating with an aeradio station and therefore not in direct contact with ATC. HF COMMUNICATIONS FAILURE In general, each aeradio station continuously listens out on its appropriate family/families of NAT HF frequencies. In the event of failure of HF communications en-route every effort should be made by the pilot to relay position reports through other aircraft. An air-to-air VHF frequency for the Region has been agreed. When out of range of VHF ground stations on the same or adjacent frequencies, 131.800 MHz may be used to relay position reports. If necessary initial contact for such relays can be established on 121.5 MHz (the frequency guarded by all aircraft operating in the NAT Region). The following procedures are intended to provide general guidance for North Atlantic (NAT) aircraft experiencing a communications failure. These procedures are intended to complement and not supersede State procedures/regulations. It is not possible to provide guidance for all situations associated with a communications failure. General. If so equipped, the pilot of an aircraft experiencing a two way communications failure shall operate the secondary radar transponder on identity Mode A Code 7600 and Mode C. The pilot shall attempt to contact any ATC facility or another aircraft and inform them of the difficulty and request they relay information to the ATC facility with whom communications are intended. Communications failure prior to entering NAT oceanic airspace. Due to the potential length of time in oceanic airspace, it is strongly recommended that a pilot experiencing communications failure whilst still in domestic airspace does nor enter the Oceanic Control Area but adopts the procedure specified in the appropriate domestic AIP and lands at a suitable airport. However, if the pilot elects to continue, then to allow the ATC organisation to provide adequate separation, adopt one of the following procedures. If the pilot has received and acknowledged an oceanic clearance, the pilot shall enter oceanic airspace at the cleared oceanic entry point, level and speed and proceed in accordance with the received and acknowledged oceanic clearance. Any level or speed changes required to comply with the oceanic clearance shall be completed in domestic airspace in the vicinity of the oceanic entry point. If the pilot has not received and acknowledged an oceanic clearance, the pilot shall enter oceanic airspace at the first oceanic entry point, level and speed as contained in the filed flight plan and proceed via the filed flight plan route to landfall. That first oceanic level and speed shall be maintained to landfall. Communications failure prior to exiting NAT oceanic airspace If cleared on flight plan route, the pilot shall proceed in accordance with the last received and acknowledged oceanic clearance to the last specified oceanic route point, normally landfall, then continue on flight plan route. Maintain the last assigned oceanic level and speed to landfall. After passing the last specified oceanic route point, conform with the relevant State procedures/regulations. If cleared on other than flight plan route, the pilot shall proceed in accordance with the last received and acknowledged oceanic clearance to the last specified oceanic route point, normally landfall. After passing this point, rejoin the filed flight plan route by proceeding directly to the next significant point ahead of the track of the aircraft as contained in the filed flight plan. Where possible use published ATS route structures, then continue on the flight plan route. Maintain the last assigned oceanic level and speed to the last specified oceanic route point. After passing this point conform with the relevant State procedures/regulations. OPERATION OF TRANSPONDERS Unless otherwise directed by ATC, pilots of aircraft equipped with SSR transponders flying in NAT flight information regions shall operate transponders continuously in Mode A/C Code 2000, except that the last assigned code shall be retained for a period of 30 min after entry into NAT airspace. This procedure does not affect the use of the special purpose codes (7500, 7600 and 7700) in cases of unlawful interference, radio failure, interception or emergency. AIRBORNE COLLISION AVOIDANCE SYSTEMS Pilots should report all ACAS Resolution Advisories which occur in the NAT region to the controlling authority for the airspace involved. Chapter 7 Application of Mach Number Technique DESCRIPTION OF TERMS The term Mach Number Technique is used to describe a technique whereby subsonic turbojet aircraft operating successively along suitable routes are cleared by ATC to maintain appropriate Mach Numbers for a relevant portion of the en-route phase of their flight. OBJECTIVE The principal objective of the use of Mach Number Technique is to achieve improved utilisation of the airspace on long route segments where ATC has no means other than position reports of ensuring that the longitudinal separation between successive aircraft is not reduced below the established minimum. Practical experience has shown that when two or more turbo-jet aircraft, operating along the same route at the same flight level, maintain the same Mach Number, they are more likely to maintain a constant time interval between each other than when using other methods. This is due to the fact that the aircraft concerned are normally subject to approximately the same wind and air temperature conditions and minor variations in speed which might increase and decrease the spacing between them tend to be neutralised over long periods of flight. PROCEDURES IN NAT OCEANIC AIRSPACE The ATC clearance includes the assigned Mach Number which is to be maintained. It is therefore necessary that information on the desired Mach Number be included in the flight plan for turbojet aircraft in NAT oceanic airspace. The normal requirement for ATC to calculate estimated times for significant points along track still remains. This is necessary for both the provision of longitudinal separation between aircraft and for co-ordination with adjacent ATC units. The prescribed longitudinal separation between successive aircraft flying a particular track at the same flight level is established over the entry point. Intervention by ATC thereafter should normally only be necessary if an aircraft is required to change its Mach Number due to conflicting traffic or change in flight level. In the application of Mach Number Technique, pilots must adhere strictly to their assigned Mach Numbers unless a specific re-clearance is obtained from the appropriate ATC unit. If an immediate temporary change in the Mach Number is essential, eg due to turbulence, ATC must be notified as soon as possible. PROCEDURE AFTER LEAVING OCEANIC AIRSPACE After leaving oceanic airspace pilots must maintain their assigned Mach Number in domestic controlled airspace to the final position contained in the oceanic clearance unless the appropriate ATC unit authorises a change. Chapter 8 Miscellaneous Procedures PROVISION OF STEP-CLIMBS Although the main flow of traffic operates on strategic clearances there is scope for en-route tactical reclearances which afford the possibility of step-climbs. Controllers will accommodate requests for step-climbs whenever possible. Pilots should maintain their last assigned Mach Number during step-climbs in oceanic airspace. If due to aircraft performance this is not feasible ATC should be advised It the time of the request. EN-ROUTE CHANGES OF MACH NUMBER The initial oceanic clearance specifies a Mach Number which pilots must adhere to. However as the aircraft weight reduces it may be more fuel efficient to adjust the Mach Number. ATC approval of requests for change in cruise Mach Number will be given if traffic conditions permit. SPECIAL PROCEDURES GANDER OCA Eastbound flights intending to operate in the Gander OCA should notify the OAC of the maximum acceptable flight level, taking into account that the climb to the assigned oceanic flight level must normally be achieved whilst the aircraft is within radar coverage. Such flights should also notify the OAC of any required change to their oceanic flight planned level, track or Mach Number as soon as possible after departure to assist the OAC in preplanning optimum airspace utilisation. USE OF FL330 WESTBOUND AND FL350 EASTBOUND Flights planning to operate wholly or partly outside the NAT OTS should flight plan level(s) appropriate to the direction of flight except that during the westbound OTS, westbound aircraft may flight plan level 330, and during the eastbound OTS, eastbound aircraft may flight plan level 350. SPECIAL ARRANGEMENTS FOR THE PENETRATION OF MNPS AIRSPACE BY AIRCRAFT INTENDING TO OPERATE ABOVE MNPS AIRSPACE Aircraft not approved for operation in MNPS airspace may be cleared by the responsible ATC unit to climb or descend through MNPS airspace provided: the climb or descent can be completed within the coverage of selected VOR/DMEs and/or within radar coverage of the ATC unit issuing such clearance and the aircraft is able to maintain direct pilot-controller communications on VHF; and MNPS aircraft operating in that part of the MNPS airspace affected by such climbs of descents are not penalised. Chapter 9 Aircraft Minimum Navigation Capability GENERAL It is implicit in the concept of MNPSA that all flights within the airspace achieve the highest standards of navigation performance accuracy. Thus all flights within the NAT MNPSA must have the approval of either the State of Registry of the aircraft, or the State of Registry of the Operator. Such approvals encompass all aspects of the expected navigation performance accuracy of the aircraft, including the navigation equipment carried, installation and maintenance procedures and crew navigation procedures and training. These matters are addressed in NAT Doc. 001. T13.5N Guidance and Information Material concerning Air Navigation in the North Atlantic Region, which is prepared by the European Office of ICAO, Paris. This document is provided to assist States of Registry, and also Operators, Owners and Planning Staff who are responsible for obtaining MNPS approvals for their aircraft. However the ultimate responsibility for checking that a flight has the necessary approval for NAT MNPS operations rests with the Pilot in Command. In most cases this check is a matter of simple routine but pilots of special charter flights, private flights, ferry and delivery flights are advised to pay particular attention to this matter. Routine monitoring of NAT traffic regularly reveals examples of non-approved flights from within these user groups. All such instances are prejudicial to the safety of the MNPS concept and are referred to the relevant State Authorities for further action. Certification Certification for MNPS will call for checking of various aspects, including crew competence and drills, navigation equipment suitability and maintenance, etc by the State of Registry or State of the operator, as appropriate, for the conduct of such operations. NAVIGATION EQUIPMENT FOR UNRESTRICTED MNPSA OPERATIONS There are two navigational requirements for aircraft planning to operate in the MNPSA. One refers to the navigation performance which should be achieved, in terms of accuracy. The second refers to the need to carry stand-by equipment with comparable performance characteristics (ICAO Annex 6 Parts 1 and 2 Chapter 7 refers). Thus in order to justify consideration for State approval for unrestricted operation in the MNPSA an aircraft will be required to be equipped as follows: - Two fully serviceable LRNSs. A LRNS may be one of the following: One Inertial Navigation System; One OMEGA Navigation System; or One navigation system using the inputs from one or more IRS or OSS or any other sensor system complying with MNPS specifications. Each LRNS must be capable of providing a continuous indication to the flight crew of the aircraft position relative to track. It is highly desirable that the navigation system employed for the provision of steering guidance is capable of being coupled to the auto-pilot. PARTIAL OR COMPLETE LOSS OF NAVIGATION/FMS CAPABILITY BY AIRCRAFT HAYING STATE APPROVAL FOR UNRESTRICTED OPERATIONS IN MNPSA Some aircraft carry triplex equipment (3 x LRNSs) and hence if one system fails even before take off, the two basic requirements for MNPSA operations may still be unaffected and the flight can proceed normally. The following guidance is offered for aircraft equipped with only two operational LRNSs: One System Fails Before Take-Off The pilot should consider: delaying departure if timely repair is possible; obtaining a clearance above or below MNPS airspace; planning on the special routes which have been established for use by aircraft suffering partial loss of navigation capability namely: * STN/BEN - 61ºW 10ºW - ALDAN - KEF * STN/BEN - 60ºN 10ºV - 61ºW 12º34'W - ALDAN - KEF * SNN/MAC/BEL/GOW - 57ºN 10ºW - 60ºW 15ºW - 61ºW 16º 30'W - BREKI - KEF * KEF - EMBLA - 63ºN 30º W - 61ºN 40ºW - OZN * KEF - GIMLI - KK - SF - FROBAY * OZN - 59º N 50ºW - PRAWN - NAIN * OZN - 59ºN 50ºW - PORGY - HO * OZN - 58ºN 50ºW - LOACH - YYR Subject to the following conditions: - sufficient navigation capability remains to meet the MNPS accuracy and the requirements in Annex 6 Part 1 Chapter 7 for redundancy can be met by relying on short range navaids; - a revised flight plan is filed with the appropriate ATS unit; - an appropriate ATC clearance is obtained. One System Fails Before the Oceanic Boundary is Reached The pilot will have to consider: landing at a suitable aerodrome before the boundary or returning to the aerodrome of departure; diverting by a special route indicated above subject to the same conditions; obtaining a reclearance above or below MNPS airspace. One System Fails After the OCA Boundary is Crossed Once the aircraft has entered oceanic airspace the pilot should normally continue to operate the aircraft in accordance with the oceanic clearance already received, appreciating that the reliability of his total navigation system has been significantly reduced. He should however, assess the prevailing circumstances (eg performance of the remaining system, remaining portion of the flight in MNPS airspace etc); prepare a proposal to ATC with respect to the prevailing circumstances (eg request clearance above or below MNPS airspace, turnback, obtain clearance to the special routes etc); advise and consult with ATC as to the most suitable action; obtain appropriate clearance prior to any deviation from oceanic clearance. When the flight continues in accordance with its original clearance (especially if the distance ahead within MNPS airspace is significant), the Pilot should begin a special monitoring programme: to take special care in the operation of his remaining system taking account of the fact that his routine method of error checking is no longer available; to check the main and standby compass systems against the information which he has available. to check the performance record of the remaining equipment and if doubt arises regarding the performance and/or reliability he should consider: - attempting visual sighting of other aircraft or their contrails which may provide a track indication; - calling the appropriate OAC to obtain information on aircraft adjacent to his estimated position and/or calling on VHF to establish contact with such aircraft (preferably same track/level) obtaining from them information which could be useful (drift, magnetic heading, wind details). The Remaining System Fails After Entering MNPS Airspace (Or the remaining system gives an indication of degradation of performance, or neither system fails completely but the system indications diverge widely and the defective system cannot be determined.) The pilot should: notify ATC; make best use of procedures specified above relating to attempting visual sightings and establishing contact on VHF with adjacent aircraft for useful information. keep a special look-out for possible conflicting aircraft, and make maximum possible use of exterior lights; if no instructions are received from ATC within a reasonable period consider: - climbing or descending 500 feet if below FL 290; - climbing or descending 1000 feet if above FL 290; - climbing 1000 feet or descending 500 feet if at FL 290; - broadcast action on 121.5 MHz; and advising ATC as soon as possible Complete Failure of Navigation Systems Computers A characteristic of the Navigation Computer System is that the computer element might fail and thus deprive the aircraft of steering guidance and the indication of position relative to Cleared Track, but the raw outputs of the IRS/OSS (LAT/LONG; Drift and Groundspeed) would be left unimpaired. A typical drill to minimise the effects of a total Navigation Computer System failure is suggested below. It requires the carriage of a suitable plotting chart (Note the AERAD Charts NAT 1 and 2 at 1:8.5 Million scale; the JEPPESEN CHARTS AT ((H/L) 1 and 2 at 1:9.9 Million; and the JEPPESEN North/Mid Atlantic Plotting Chart (1:8.75 Million) are considered suitable for this purpose). Draw Cleared Route on charts, extract mean true tracks between waypoints. Use the IRS/OSS outputs to adjust heading to maintain mean track and to calculate ETAs. At intervals of not more than 15 minutes plot position (LAT/LONG) on chart and adjust heading to regain track. PERFORMANCE MONITORING The navigation performance of Operators within NAT MNPS Airspace is monitored; on a continual basis. If a deviation is identified follow-up action is taken both with the Operator and the State of Registry of the aircraft involved to establish the cause of the error and to confirm the approval of the flight to operate in NAT MNPS Airspace. The overall navigation performance of all aircraft in the MNPSA is compared with the Target Level of Safety (TLS) established for the Region to ensure that the necessary standards are being maintained. The format of the Error Investigation Form used for follow-up action is as shown at Attachment 2. Chapter 10 Special Procedures for In-Flight Contingencies INTRODUCTION The following procedures are intended for guidance only. Although all possible contingencies cannot be covered, they provide for such cases as inability to maintain assigned level due to weather, aircraft performance or pressurisation failure. They are applicable primarily when rapid descent, turnback, or both are required. The pilot's judgement shall determine the sequence of actions taken, having regard to the specific circumstances. GENERAL PROCEDURES If an aircraft is unable to continue flight in accordance with its air traffic control clearance, a revised clearance shall, whenever possible, be obtained prior to initiating any action, using the radio telephony distress or urgency signal as appropriate. If prior clearance cannot be obtained, an air traffic control clearance shall be obtained at the earliest possible time and, in the meantime, the aircraft shall broadcast its position (including the ATS Route designator or the Track Code as appropriate) and intentions on 121.5 MHz at frequent intervals. SPECIAL PROCEDURES Initial Action If unable to comply with the above provisions, the aircraft should leave its assigned route or track by turning 90º to the right or left whenever this is possible. The direction of the turn should be determined by the position of the aircraft relative to any organised route or track system (eg whether the aircraft is outside, at the edge of, or within the system). Other factors which may affect the direction of turn are the direction to an alternate airport, terrain clearance and the levels allocated on adjacent routes or tracks. Subsequent Action An aircraft able to maintain its assigned level should: If above FL 290, climb or descend 1000 ft; If below FL 290, climb or descend 500 ft; If at FL 290. climb 1000 ft or descend 500 ft, while acquiring and maintaining in either direction a track laterally separated by 30 nm from its assigned route or track. An aircraft not able to maintain its assigned level should start its descent while turning to acquire in either direction a track laterally separated by 30 nm from its assigned route or track. For subsequent level flight, a level should be selected which differs from those normally used by 1000 ft if above FL 290, or by 500 ft if below FL 290. En-route diversion across the prevailing NAT air traffic flow In the event of a contingency which necessitates an en-route diversion to an alternate aerodrome across the direction of the prevailing NAT traffic flow, and prior ATC clearance cannot be obtained: An aircraft able to maintain its assigned flight level should: if above FL 290, climb or descend 1000 ft; if below FL 290, climb or descend 500 ft; if at FL 290, climb 1000 ft or descend 500 ft; while turning towards the alternate aerodrome; An aircraft not able to maintain its assigned level should: start its descent while turning to acquire a track separated by 30 NM from its assigned route or track; continue descent to a level which can be maintained and which differs from those normally used by 1000 ft if above FL 290 or by 500 ft if below FL 290 before making a further turn towards the alternate aerodrome; If these contingency procedures are employed by a twin-engined aircraft as a result of a shutdown of a power unit or a primary aeroplane system failure, the pilot should so advise ATC as soon as practicable, reminding ATC of the type of aircraft involved and requesting expeditious handling. Chapter 11 MNPS Cross-Check Procedures INTRODUCTION The aircraft navigation systems necessary for flying In NAT MNPSA are capable of high performance standards. However it is essential that stringent navigational cross-checking procedures are employed to ensure that these systems perform to their full capabilities. Navigation systems are continuously evolving and past editions of this Manual have concentrated on offering specific guidance on the use of individual systems. Rather than specifying the types of equipment required for flying in defined airspace, current thinking is moving towards specifying a required navigation performance capability (RNPC), in other words a track keeping capability. Obviously there are several combinations of airborne sensors, receivers, computers with navigation data bases and displays which are capable of producing like accuracies, with inputs to automatic flight control systems giving guidance from point to point. No matter how sophisticated or mature a system is, it is still essential that stringent navigational cross checking procedures are maintained if gross errors are to be avoided. The procedures listed in this chapter are not intended to be equipment specific and may not all be pertinent to every aircraft. For specific equipments, reference should be made to manufacturers' and operators' handbooks and manuals. There are various references in this material to two pilots, however when carried, a third crew member should be involved in all cross check procedures to the extent practicable. Maintenance of a high standard of navigation performance is absolutely essential to the maintenance of safety in the NAT MNPSA GENERAL PROCEDURES The use of a Master Document The navigation procedures must include the establishment of some form of master working document to be used on the flight deck. This document may be based upon the flight plan, navigation log, or other suitable document which lists sequentially the waypoints defining the route, the tracks and distances between each waypoint, and other information relevant to navigation along the cleared track. When mentioned subsequently in this guidance material, this document will be referred to as the 'master document'. Misuse of the master document can result in gross navigation errors being made and for this reason strict procedures regarding its use should be established. These procedures should include the following: Only one master document shall be used on the flight deck. However this does not preclude other crew members maintaining a separate flight log. A waypoint numbering sequence should be established from the outset of the flight and entered on the master document. The identical numbering sequence should be used in storing waypoints in the navigation computers. An appropriate symbology should be adopted to indicate the status of each waypoint listed on the master document. Following is a typical example of an INS/ONS routine. IRS/FMS procedures slightly differ but the principles are the same. The waypoint number is entered against the relevant waypoint co-ordinates to indicate that the waypoint has been inserted in the navigation computers. The waypoint number is circled, to signify that insertion of the correct co-ordinates in the navigation computers has been double-checked independently by another crew member. The circled waypoint number is ticked, to signify that the relevant track and distance information have been double- checked. The circled waypoint number is crossed out, to signify that the aircraft has overflown the waypoint concerned. All navigational information appearing on the master document must be checked against the best available prime source data. When a reroute is necessary, it is recommended that a new master document is prepared for the changed portion of the flight. If the original master document is to be used the old way points should be clearly crossed out and the new ones entered in their place. When ATC clearances or reclearances are being obtained headsets should be worn, because the inferior clarity of loud-speakers has been know to result in mistakes. Two qualified crew members should monitor such clearances, one of them recording the clearance on the master document as it is received, the other checking the receipt and read-back. All waypoint co-ordinates should be read back in detail using strict ICAO phraseology except where approved local procedures make this unnecessary. Detailed procedures pertaining to abbreviated clearances are contained in the appropriate AIPs. Position Plotting It is very helpful for crews to use a simple plotting chart to provide themselves with a visual presentation of the intended route which, otherwise, is defined only in terms of navigational co-ordinates. Merely plotting the intended route on such a chart may reveal errors and discrepancies in the navigational co-ordinates which can then be corrected immediately, before they reveal themselves in terms of a deviation from the ATC cleared route. As the flight progresses, plotting the aircraft's position on this chart will also serve the purpose of a navigation cross check, provided that the scale and graticule are suitable. As the flight progresses in oceanic airspace, plotting the aircraft's position on this chart will help to confirm (when it falls precisely on track) that the flight is proceeding in accordance with its clearance. But if the plotted position is laterally offset, the flight may be deviating unintentionally, and this possibility should be investigated at once. It is recommended that a chart with an appropriate scale be used for plotting. Many company progress Charts are of the wrong scale or too small. The AERAD NAT 1/2, and the JEPPESEN AT (H/L) 1/2 are both useful compromises between scale and overall chart size, while the NOAA/FAA North Atlantic Route chart has the advantage, for plotting purposes, of a 1º latitude/longitude graticule. Relief Crew Members Flight crews conducting very long range operations may include extra relief crew. In such cases it is necessary to ensure that the navigational procedures are such that the continuity of the operation is not interrupted, particularly in respect of the handling and treatment of the navigational Information. System Alignment (Inertial Systems) The alignment of inertial systems must be completed and the equipment put into navigation mode prior to releasing the parking brake at the ramp. Some systems will align in about 10 minutes, others can take 15 minutes or more; expect alignment to take longer in extreme cold. A rapid realignment feature is sometimes provided but should only be used if, during an intermediate stop, it becomes necessary to increase the system accuracy. The aircraft must be stationary during rapid realignment which typically will take about one minute. To ensure that there is adequate time for the initial alignment, the first crew member on the flight deck should normally put the inertial system(s) into the align mode as soon as practicable. Omega Synchronisation In the absence of abnormally high radio noise levels, the synchronisation of Omega usually takes only a minute or so after switch on. At certain ramp or gate positions, however, particularly those where metal structures interfere with Omega signals, synchronisation may take longer or the inserted ramp co-ordinates may drift after insertion. Interference from ground-vehicles such as baggage trucks, can have a similar effect. Warning lights usually indicate this situation. If the Omega equipment is serviceable the problem normally disappears shortly after the equipment is switched to aircraft power or the aircraft is moved, but it is good practice to check present position co-ordinates immediately before take-off and if necessary make a correction. The initial Insertion of Latitude and Longitude For inertial systems any latitude error in the initial position can Introduce a systematic error which cannot be removed in flight, even by updating the present position. Correct insertion of the initial position must therefore be checked before inertial systems are aligned and the position should be recorded in the flight log and/or master document. Subsequent 'silent' checks of the present position should be carried out independently by both pilots during an early stage of the pre-flight checks. With regard to the insertion whilst on the ramp of the initial co-ordinates, the following points should be taken into account. In some inertial systems, insertion errors exceeding about one degree of latitude will illuminate a malfunction light. It should be noted that very few systems provide protection against longitude insertion errors. At all times but particularly in the vicinity of the equator or the prime meridian, care should be taken to ensure that the co-ordinates inserted are correct. (i.e. N/S or E/W). Loading of initial Waypoints. The manual entry of waypoint data into the navigation systems must be a co-ordinated operation by two persons, working in sequence and independently: one should key in and insert the data and subsequently, the others should recall it and confirm it against source information. It is not sufficient for one crew member just to observe another crew member inserting the data. The ramp position of the aircraft, at least two additional waypoints, and, if the onboard equipment allows all the waypoints relevant to the flight should be loaded while the aircraft is at the ramp. However, it is more important to ensure that the first enroute waypoint is inserted accurately. During flight, at Least two current waypoints beyond the leg being navigated should be maintained in the Control Display Units (CDU) until the destination ramp coordinates are loaded. The two pilots should be responsible for loading, recalling and checking the accuracy of the inserted waypoints; one loading and the other recalling and checking them independently. Where remote loading of the units is possible, this permits one pilot to cross-check additionally that the data inserted by the other is accurate. This process should not be permitted to engage the attention of both pilots simultaneously during the flight. An alternative and acceptable procedure is for the two pilots silently and independently to load their own initial waypoints and then cross-check them. The pilot responsible for carrying out the verification should work from the CDU display to the master document rather than in the opposite direction. This may lessen the risk of his 'seeing what he expects to see' rather than what is actually displayed. Flight Plan Check The purpose of this check is to ensure complete compatibility between the master document and the programming of the navigation systems. Check the distance from the ramp position to the first waypoint. Some systems will account for the track distance involved in an ATC SID; on others, an appropriate allowance for a SID may have to be made to the great circle distance indicated. If there is significant disagreement, recheck initial position and waypoint coordinates. Select track 1-2 and do the following checks: check the accuracy of the indicated distance against that of the master document; check if possible that the desired track displayed is as listed in the master document. (This check will show up any errors made in lat/long designators (ie N/S or E/W)). Similar checks should be carried our for subsequent pairs of waypoints and any discrepancies between the master document and displayed data checked for possible waypoint insertion errors. These checks can be co-ordinated between the two pilots checking against the information in the master document. When each leg of the flight has been checked in this manner it should be annotated on the master document by means of a suitable symbology as previously suggested. Some systems have integral navigation databases and it is essential that the currency of the database being-used is known. Remember that someone, somewhere along the data input chain, at some past time, has keyed in waypoint positions and matter how sophisticated your system, the possibility of Input error is always present. Do not assume the infallibility of navigation databases and maintain the thorough procedures used in checking your own manual inputs. Leaving the Ramp The aircraft must not be moved prior to the navigation mode being initiated, otherwise inertial navigation systems must be realigned. After leaving the ramp, inertial groundspeeds should be checked (a significantly erroneous reading may indicate a faulty or less reliable unit). A check should be made on any malfunction codes whilst the aircraft is stopped but after it has taxied at least part of the way to the take-off position; any significant ground-speed indications whilst stationary may indicate a faulty' unit such as a tilted platform. This check does not normally apply in the in case of Omega because generally speaking such equipment is inhibited from providing a speed indication until the aircraft is airborne. Omega present position co-ordinates should be checked before take-off if there has been any possibility of error induced by signal interference. IN FLIGHT PROCEDURES Whilst on airways If the initial part of the flight is conducted along airways, ground navaids should be used to verify the performance of the long range navigation systems. ATC Oceanic Clearance Where practicable, two flight crew members should listen to and record every ATC clearance and both agree that the recording is correct. Any doubt should be resolved by requesting clarification from ATC. If the ATC Oceanic clearance is identical to the flight-planned track, it should be drawn on the plotting chart and verified by the other pilot. If the aircraft is cleared by ATC on a different track from that flight-planned, it is strongly recommended that a new master document be prepared showing the details of the cleared track. Overwriting of the existing flight plan can cause difficulties in reading the waypoint numbers and the new co-ordinates. For this purpose, a pro-forma should be carried with the flight documents. One flight crew member should extract track and distance data from the appropriate reference source and this should be checked by another crew member. If necessary, a new plotting chart may be used on which to draw the new track. The new document(s) should be used for the oceanic crossing. If the subsequent airways section of the flight corresponds to that contained in the original flight-plan, it should be possible to revert to the original master document at the appropriate point. Experience suggests that when ATC issues a re-clearance involving re-routing and new waypoints, there is a consequent increase in the risk of errors being made. Therefore, this situation should be treated virtually as the start of a new flight, and the procedures employed with respect to copying the ATC reclearance, amending the master document, loading and checking waypoints, extracting and verifying flight plan information, tracks and distances, etc, and the preparation of a new chart should be identical to the procedures employed at the beginning of a flight. Strict adherence to the above procedures should minimise this risk. However, flight deck management should be such that one pilot is designated to be responsible for flying the aircraft while the amendments to the documentation and the reprogramming of the navigation systems are being carried out. Approaching the Ocean Prior to entering the MNPSA, the accuracy of the long range navigation systems should be checked thoroughly by using independent navigation aids. For example, position can be checked against raw data from VOR radials plus distances from DMEs or from 'overheads' of VORs or NDBs. The introduction of Global Navigation Satellite Systems (GNSS) will, when they are certified for use, give another source of accurate position checking. The navigation system which has performed most accurately since departure should be selected for automatic navigation steering. In view of the importance of following the correct track in oceanic airspace, some operators advise that at this stage of the flight the third pilot or equivalent crew member should check the clearance waypoints which have been inserted into the navigation system, using source information such as the track message or data link clearance if applicable. Entering the MNPSA and Reaching an Oceanic Waypoint. When passing waypoints. the following checks should be carried out: Just prior to the waypoint, check the present position co-ordinates of each navigation system against the cleared route in the master document, and Check the next two waypoints in each navigation system against the master document. At the waypoint, check the distance to the next way point, confirm that the aircraft turns in the correct direction and takes up a new heading and track appropriate to the leg to the next waypoint. Before transmitting the position report to ATC verify the waypoint co-ordinates against the master document and those in the steering navigation system. After the ATC position report has been sent, the present position of the aircraft should be plotted (approximately 10 mins after the waypoint and midway between waypoints) to confirm correct tracking. At this stage the crew should be prepared for possible ATC follow up to the position report. Routine Monitoring It is important to remember that there are a number of ways in which the autopilot may unobtrusively become disconnected from the steering mode, therefore regular checks of correct engagement with the navigation system should be made. Although it is common practice to display distance and time, it is recommended that where possible the navigation system coupled to the autopilot should display the present position coordinates throughout the flight. If these are then plotted as suggested above, they will provide confirmation that the aircraft is tracking in accordance with its ATC clearance. Distance to go information should be available on the instrument panel as previously mentioned, while a waypoint alert light, where fitted, provides a reminder of the imminence of the waypoint. If a position check is being made both at each waypoint and 10 minutes after each waypoint, additional plots may perhaps be unnecessary as a normal routine. Even so there may be circumstances, (eg when the flight is down to one system only) justifying additional plots 20 minutes after each waypoint. For INS ONS fitted aircraft, the navigation system not being used to steer the aircraft should display cross-track distance and track angle error. These should be monitored, with cross-track distance being displayed on the HSI where feasible. Approaching Landfall When the aircraft is within range of land based navaids, and the crew is confident that these navaids are providing reliable navigation information, consideration should be given to updating the long range navigation systems. Automatic updating of inertial navigation systems from other navaids (eg DMEs) should be closely monitored. SPECIAL IN FLIGHT PROCEDURES Monitoring during Distractions from Routine Training and drills should ensure that minor emergencies or interruptions to normal routine are not allowed to distract the crew to the extent that the navigation system is mishandled. If during flight the auto pilot is disconnected (eg. because of turbulence), care must be taken when the navigation steering is re-engaged to ensure that the correct procedure is followed. If the system in use sets a specific value on the boundary of automatic capture, the across-track indications should be monitored to ensure recapture of the programmed flight path. Where crews have set low angles of bank, say 10º or less, say for passenger comfort considerations, it is essential to be particularly alert to possible insidious departures from the cleared track. Avoiding Confusion between Magnetic and True To cover all navigation requirements, some airlines produce flight plans giving both magnetic and/or true tracks (courses). However, especially if crews are changing to a new system, there is a risk that at some stage (e.g. partial system failure, reclearances, etc.), confusion may arise in selecting the correct values. Operators should therefore devise drills which will reduce this risk, as well as ensuring that the subject is covered during training. Crews who decide to check or up-dare their long-range navigation systems by reference to VORs should remember that in the Canadian Northern Control Area these are aligned with reference to true north. Navigation in the Area of Compass Unreliability In areas of compass unreliability basic inertial navigation requires no special procedures but most operators feel it is desirable to retain an independent heading reference in case of system failure. Omega requires heading input from an external source. Different manufacturers may offer their own solutions to the special problems existing in the areas of compass unreliability. Such solutions should not however involve the use of charts and manual measurement of direction. Deliberate Deviation from Track Deliberate temporary deviations from track are sometimes necessary, usually to avoid severe weather. Whenever possible prior ATC approval should be obtained. Such deviations have often been the source of gross errors as a consequence of failing to re-engage the autopilot with the navigation system. It should also be noted that selection of the 'turbulence' mode of the autopilot on some aircraft may have the effect of disengaging it from the aircraft navigation system. After use of the turbulence mode, extra care should be taken to ensure that the desired track is recaptured by the steering navigation system. PROCEDURES IN THE EVENT OF SYSTEM DEGRADATION Detection of Failures. Inertial and Omega installations normally include comparator and/or warning devices, but it is still necessary for the crew to make frequent comparison checks. With three systems on board, the identification of a defective system should be straightforward, although it should be noted that during the acceleration phases of flight Omega groundspeed indications (unless over ridden by some form of rate-aiding) are likely to be less accurate than inertial navigation systems and should not be used in comparison checks. With only two systems on board, identifying the defective unit can be difficult. If such a situation does arise in oceanic airspace it may be possible to contact nearby aircraft on VHF and obtain the read-out of spot wind (or if aircraft are going in the same direction, drift and ground speed) and make use of this information to identify the defective system. Inertial navigation systems have proved to be highly accurate and very reliable in service. Manufacturers claim a drift rate of less than 3 nm per hour, however in practice IRSs with laser gyros are proving to be accurate to less than 1 nm per hour. This in itself can lead to complacency but failures do still occur. Close monitoring of divergence of output between individual systems is essential if errors are to be avoided and faulty units identified. Methods of Determining which System Is Faulty Check malfunction codes for indication of unserviceability. Obtain a fix. It may be possible to use the weather radar (range marks and relative bearing lines) to determine the position relative to an identifiable landmark such as an island; or the ADF to obtain bearings from a suitable NDB, in a-which case the variation at the position of the aircraft should be used to convert the RMI bearings to true; or if within range, the VOR, in which case the variation of the VOR location should be used to convert the radial to a true bearing (except when flying in the Canadian Northern Control area). Contact a nearby aircraft on VHF, and compare information on spot wind. or ground speed and drift. If such assistance is not available, as a last resort the wind speed and direction for the DR position of the aircraft may be extracted from the Flight Plan for comparison with navigation system outputs. Action if the Faulty System can not be identified Occasions may still arise when distance or across track differences develop between systems, but the crew cannot determine which system is at fault. The majority of airlines feel that the procedure most likely to limit gross tracking errors under such circumstances is to fly the aircraft half way between the cross track differences as long as the uncertainty exists. In such instances ATC should be advised that the flight is experiencing navigation difficulties so that appropriate separation can be effected if necessary. Guidance on what constitutes a Failed System Operations or navigation manuals should include guide lines on how to decide when a navigation system should be considered to have failed, eg failures may be indicated by a red warning light, or by self diagnosis indications, or by an error over a known position exceeding the value agreed between an operator and its certifying authority. As a generalisation, if there is a difference greater than 15 nm between two aircraft navigation systems (or between the three systems if it is not possible to detect which are the most reliable) it is advisable to split the difference between the readings when determining the aircraft's position. However, if the disparity exceeds 25 nm one or more of the navigation systems should be regarded as having failed, in which case ATC should be notified. AFTER FLIGHT PROCEDURES Navigation System Accuracy Check At the end of each flight an evaluation of accuracy of the aircraft's navigation systems should be carried out. Equipment operating manuals specify maxima for radial errors before a system is considered to be unserviceable. These are in the order of 3 or 4 nm per hour. One method used to determine radial error is to input the shutdown ramp position, other systems output error messages giving differences between raw inertial reference positions and computed radio nav updated positions. Whatever method is used, records should be kept of the aircraft navigation systems performance. Chapter 12 A Check List for Pilots Not Familiar With Operations in NAT MNPS Airspace To assist those pilots who are less familiar with operating in the area, the following short check list has been prepared: 1. Are you sure that your State of Registry has granted MNPS approval to this flight? 2. if it has, hive you put the letter X in Item 10 of your flight plan? 3. If you are intending to follow an organised track, and bearing in mind that the OTS changes every 12 hours, have you got a copy of the valid track message? 4. Are you familiar with the Mach Number technique? 5. Have you had an accurate time check, and do you have a reliable timepiece on the flight deck? 6. If using OMEGA, have you checked the latest NOTAMs regarding the serviceability of OMEGA (and VLF) Stations, if appropriate? 7. If flying via the special Greenland/Iceland routes, have you checked the serviceability both of your one long range navigation facility and of the short range navigation facilities which you will use? 8. if flying a non-H/F equipped aircraft is your route approved for VHF only? 9. If flying other than on the special routes, are you sure of the serviceability of both your long range navigational systems? 10. Have you planned ahead for your action should you suffer a failure of one system? If as a pilot you have any doubt about your answers to these questions, it may be necessary for you to consult with the Civil Aviation Department of your State of Registry. Chapter 13 Guarding Against Complacency INTRODUCTION Especially since 1977, when the MNPS rules were introduced, careful monitoring procedures have enabled the NAT Provider States to obtain a good indication, both of the frequency with which navigation errors occur, and their causes. Their frequency is low, and only one aircraft in many thousands is found to have a serious navigation error. Navigation systems are now so reliable that a typical crew member could theoretically spend his complete career flying across the Atlantic without ever being more than five miles from cleared track. Not surprisingly this may eventually lead in some cases to over-confidence. RARE CAUSES OF ERRORS To begin with and to illustrate the surprising nature of things which can go wrong, here are examples of some extremely rare faults which have occurred: The lat/long co-ordinates displayed near the gate position at one international airport were wrong. Because of a defective chip in one of the INS systems on an aircraft, although the correct forward latitude was inserted by the crew (51º) it subsequently jumped by one degree to (52º). The aircraft was equipped with an advanced system with all the co-ordinates of the waypoints of the intended route already in a database; the crew assumed that these co-ordinates were correct, but one was not. When crossing 40ºW westbound the Captain asked what co-ordinates he should insert for the 50ºW waypoint and was told 48 50. He wrongly assumed this to mean 48º50'N at 50º00W and as a result deviated 50 mls from track. The flight crew had available to them the correct co-ordinates for their cleared track, but unfortunately the data which they inserted into the navigation computer was from the company flight plan, in which an error had been made. At least twice since 1989, longitude has been inserted with an error of magnitude of times 10 e.g. 100W vice 10W or 5W vice 50 W. Because of low angles of bank, the aircraft departed from track without the crews being aware, and both lateral and longitudinal separations were lost. COMMONER CAUSES OF ERRORS However. the most common causes of gross errors, in approximate order of frequency, have been as follows: A mistake of one degree of latitude has been made in inserting a forward waypoinr. There seems to be a greater tendency for this error to be made when a track, after passing through the same latitude at several waypoints (eg 57ºN 50ºW, 57ºN 40ºW, 57ºN 30ºW) changes by one degree (eg 56ºN 20ºW). Other circumstances which can lead to this mistake being made include getting a reclearance in flight. The crew have been recleared by ATC, or have asked for and obtained a reclearance. But they have forgotten to re- programme the navigation system(s). The auto-pilot has been inadvertently left in the heading or de-coupled position after avoiding clouds, or left in the VOR position after leaving the last domestic airspace VOR. In some cases the mistake has arisen during distraction caused by SELCAL or by some flight deck warning indication. An error has arisen in the ATC-loop, so that the controller and the crew have had different understandings of the clearance. In some cases the pilot has heard not what was said, but what he expected to hear said. LESSONS TO BE LEARNT Never relax or be casual in respect of the cross-check procedure, this is especially important towards the end of a long night flight. Avoid casual RT procedures. A number of gross errors have been the result of a misunderstanding between pilot and controller as to the cleared route. Adhere strictly to proper phraseology and do not be tempted to clip or abbreviate details of waypoint co-ordinates. Make an independent check on the gate position. Do not assume that the gate coordinates are correct without cross- checking with an authoritative source. Normally, of course, you expect coordinates to be to the nearest tenth of a minute, so make sure that the display is not to the hundredth, or in minutes and seconds. And if you are near to the prime meridian, remember the risk of confusing east and west. Before entering Oceanic Airspace make a careful check of LRNS positions at or near to the last radio facility - or perhaps the last but one. Do not assume that you are at a waypoint merely because the alert annunciator indicates; cross-check by reading present position. Flight deck drills. There are some tasks on the flight deck which can safely be delegated to one member of the crew, but navigation using automated systems is emphatically not one of them, and the Captain should participate in all navigation cross-check procedures. Initialisation errors: Always return to the ramp and re-initialise inertial systems if the aircraft is moved before the navigation mode is selected. If after getting airborne it is found that during initialisation a longitude insertion error has been made, unless you thoroughly understand what you are doing, and have also either had recent training on the method or carry written drills on how to achieve the objective, you should not proceed into MNPS airspace, but should turn back or make an en-route stop. Waypoint loading. Before departure, make a check that the following agree: computer flight plan, ICAO flight plan, track plotted on chart, and if appropriate, track message. In flight, involve two different sources in the cross-checking, if possible. Do not be so hurried in loading waypoints that mistakes become likely, and always check waypoints against the current ATC clearance, Use a flight progress chart on the flight deck. It has been found that making periodic plots of position on a suitable chart and comparing with current cleared track, greatly helps to pick up errors before getting too far from track. Consider making a simple use of basic DR Navigation as a back-up. Outside polar regions, provided that the magnetic course (track) is available on the flight log, a check against the magnetic heading being flown, plus or minus drift, is likely to indicate any gross tracking error. Always remember that something absurd may have happened in the last half-hour. There are often ways in which an overall awareness of directional progress can be maintained; the position of the sun or stars; disposition of contrails; islands or coast-lines which can be seen directly or by using radar; radio nav-aids. and so forth. This is obvious stuff, but some of the errors which have occurred could have been prevented if the crew had shown more of this type of awareness. If you suspect that equipment failure may be leading to divergence from cleared track, it is better to advise ATC early rather than late. In conclusion. navigation fits vary greatly between operators. If any of the above does not apply in your case, remember that it may help to prevent someone else making a mistake, and may stimulate you to avoid mistakes of a similar nature. Chapter 14 The Prevention of Deviations From Track as a Result of Waypoint Insertion Errors THE PROBLEM During the monitoring of navigation performance in the NAT MNPS airspace a number of Gross Navigation Errors (GNE) are reported (27 in 1992) A GNE is defined as a deviation from cleared track of 25 nms or more, and these errors are normally detected by means of long range radars as aircraft leave oceanic airspace. Occasionally errors are identified through the scrutiny of routine position reports from aircraft. Investigations into the causes of all deviations show that about 50% were attributable to equipment control errors by crews and that almost all of these errors were the result of the programming of the navigation system(s) with incorrect waypoint data - waypoint insertion errors. THE CURE Waypoint insertion errors could be virtually eliminated if all operators/crews adhered at all times to approved operating procedures and cross checking drills. To this end the NAT MNPSA Operations Manual provides a considerable amount of guidance and advice based on experience gained the hard way, but it is quite impossible to provide specific advice for each of the many variations of navigation fit. The following procedures are recommended as being a good basis for MNPS operating drills/checks: Record the initialisation position programmed into the navigation computer. This serves two purposes: it establishes the starting point for the navigation computations, and in the event of navigation difficulties it facilitates a diagnosis of the problem. Ensure that your flight-log has adequate space for the ATC cleared track co-ordinates - and always record them. This part of the flight log then becomes the flight deck master document for: Read back of clearance Entering the route into the navigation system Plotting the route on your chart. Plot the cleared route on a chart with a scale suitable for the purpose (eg Jeppesen. Aerad, NOAA. NAT en-route charts). This allows for a visual check on the reasonableness of the route profile and on its relationship to the OTS, other aircraft tracks/positions, diversion airfields, etc. Plot your Present Position regularly on your chart. This may seem old-fashioned but, since the present position output cannot normally be interfered with and its calculation is independent of the waypoint data, it is the one output which can be relied upon to detect gross tracking errors. Position should be checked and preferably plotted approximately 10 minutes alter passing each waypoint, and and midway between waypoints. Check the waypoint co-ordinates against those in the steering CDU before transmitting position reports Whilst the previous four procedures will detect any incipient gross errors provided that the recorded, plotted cleared route is the same as that understood by the controlling ATS authority, this drill allows ATS the opportunity to correct any misunderstanding which may have occurred over the actual route to be flown before a hazardous track deviation can develop. Attachment 1 Guidance for Aircraft Dispatchers The following information was produced in 1993 by the International Federation of Air Line Dispatchers Associations. It is intended to provide guidance to dispatchers however it is anticipated that many of the constraints identified in the text may be removed during the life of Edition 6 hence the guidance may change. In order to provide the basis for a safe and orderly flight across the Atlantic, a realistic flight plan must be prepared. A flight that is planned with attention to basic MNPS procedures and with consideration to normal ATC constraints will have a much better chance of operating routinely than one that is not. There are several points that Aircraft Dispatchers and Flight Operations Officers need to keep in mind when planning North Atlantic crossings. All NAT Track data input into the operators database should be rechecked by a person not actually involved in the input process. Errors of transposition and other typographical errors can lead to Gross Navigational Errors if not eliminated through cross-checking. While it is permissible to flight plan across the OTS at published OTS flight levels, during peak crossing times the prudent Dispatcher will provide the resources necessary to allow for reroutes and flight level changes. Random routes that remain clear of the OTS stand a better chance of being approved during busy periods. Planners are encouraged to consider operating below the OTS during peak times when their MTT is diagonal to the published OTS. When developing the Preferred Route Message, ETOP flight planners should consider enroute alternate constraints when requesting tracks from the OAC. Aircraft Dispatchers should recognise that, while it is possible to request routes that deviate from the published North American Routes and UK Domestic Transition Routes. during peak times ATC will normally only clear flights via these routes. The prudent Dispatcher will plan adequate fuel for these situations. When planning to enter Canadian airspace from a westbound random route, the Dispatcher should select a combination of Common and Non-common NAR that is appropriate to the destination. Other more optimal routes can be requested from the appropriate ATC facility. Flights planned to operate into the eastbound OTS from the southeast US, particularly from Florida, should consider that routes A699 and A700 intersect routes from the Caribbean to the east coast of the US. As a result of this, to avoid conflicts in a non radar environment, eastbound transatlantic flights using A699/700 are often held down by the New York OAC to FL270/290 until abeam Sable Island. Adequate fuel should be planned for this contingency. In all cases where a flight is planned in conflict with the OTS, including operation of flights that will cross 30W after the expiration of the tracks, when planning to cross tracks, and when planning a flight level inconsistent with the OTS, advance coordination with the appropriate OAC is recommended. While operating within the OTS, a single flight level should be planned for the crossing, however when economically attractive the crew can be briefed to request a step climb from the appropriate OAC. Attachment 2 Sample of Error Investigation Form (Name and address of reporting agency): Please complete Parts 2 and 3 [and Part 4 if applicable) of this investigation form. A copy. together with copies of all relevant flight documentation (fuel flight plan, ATC flight plan end ATC clearance) should then be returned to the above address and also to: the North Atlantic Central Monitoring Agency. Room T805 (Am, INT. 6); CAA House. 45/59 Kingsway. London WC2B 6TE. England Part 1-General Information Operator's name Aircraft identification Date/time of observed deviation Position (latitude and longitude) Observed by (radar unit) Aircraft flight level Part 2 - Detail of Aircraft and Navigation Equipment Fit Number Type INS OMEGA IRS/FMS OTHER (PLEASE SPECIFY) Single Dual Triple Model No. Navigation system programme No. State which system coupled to auto-pilot Aircraft Registration and Mode/Series Part 3 - Detailed description of Incident Please give your assessment of the actual track flown by the aircraft and the cause of the deviation (continue on a separate sheer if required) Part 4 - Only to be completed in the event of partial or full navigation failure Indicate the number of equipment units which failed INS OMEGA IRS/FMS Other Circle estimated longitude at which equipment failed 60º W 55º W 50º W 45º W 40º W 35º W 30º W 25º W 20º W 15º W 10º W 5ºW 0ºE/ W Give an estimate of the duration of the equipment failure Time of failure Time of exit from MNPS Duration of failure in MNPS at what time did you advise ATC of the failure? Thank you for your co-operation