11.1 INTRODUCTION
11.1.1 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 (for example severe turbulence);
• aircraft performance problems; or
• pressurisation failure.
11.1.2 They are applicable primarily when rapid descent, turn-back, or diversion to an alternate aerodrome is required. The pilot's judgement will determine the specific sequence of actions taken, having regard to the prevailing circumstances.
11.2 GENERAL PROCEDURES
11.2.1 If an aircraft is unable to continue its flight in accordance with its ATC clearance, a revised clearance should be obtained whenever possible, prior to initiating any action, using the radio telephony distress (MAYDAY) signal or urgency (PAN PAN) signal as appropriate.
11.2.2 If prior clearance cannot be obtained, an ATC clearance should be obtained at the earliest possible time and, in the meantime, the aircraft should broadcast its position (including the ATS Route designator or the Track Code as appropriate) and its intentions, at frequent intervals on 121.5 MHz (with 123.45 MHz as a back-up frequency). It must be recognised that due to the use of SELCAL with HF communications in North Atlantic operations, pilots' situation awareness, of other potentially conflicting traffic, may be non-existent or incomplete.
11.2.3 Until a revised clearance is obtained the specified NAT in-flight contingency procedures should be carefully followed. Detailed procedures are contained within the ICAO NAT Regional Supplementary Procedures (Doc.7030) (available at http://www.nat-pco.org/ ) and appropriate NAT Provider States’ AIPs and are paraphrased below.
11.2.4 In general terms, the aircraft should be flown at a flight level and/or on a track where other aircraft are least likely to be encountered. Maximum use of aircraft lighting should be made and a good look-out maintained. If TCAS is carried, the displayed information should be used to assist in sighting proximate traffic.
11.3 SPECIAL PROCEDURES
11.3.1 The general concept of these NAT in-flight contingency procedures is, whenever
operationally feasible, to offset from the assigned route by 30 nm# and climb or descend to a level which differs from those normally used by 500 ft if below FL410 or by 1000 ft if above FL410.
# The Special Procedures for in-flight Contingencies, contained in the NAT Regional Supplementary Procedures
(SUPPS) (Doc 7030), have been changed by Amendment 4 to the 14th Edition of the PANS ATM (Doc 4444), which becomes effective on 24 November 2005. Essentially, the change is to alter the offset distance from 30NM to 15 NM. It is expected that revised procedure will be promulgated by the States concerned, with an implementation in late 2005 early 2006. The NAT SUPPs will be amended and MNPS Operations Manual Edition 2005 will also be amended when the States implement the change.
NAT MNPS 64 Edition 2005
Initial Action
11.3.2 The aircraft should leave its assigned route or track by initially turning 90° to the right or left whenever this is feasible. The direction of the turn should, where appropriate, be determined by the position of the aircraft relative to any organised route or track system (e.g. whether the aircraft is outside, at the edge of, or within the system). Other factors which may affect the direction of turn are: direction to an alternate airport, terrain clearance, levels allocated on adjacent routes or tracks and any known SLOP off sets adopted by other nearby traffic.
Subsequent Action
11.3.3 An aircraft that is able to maintain its assigned flight level should:
• climb or descend 1000 ft if above FL410
• climb or descend 500 ft when below FL410
• climb 1000 ft or descend 500 ft if at FL410
11.3.4 An aircraft that is unable to maintain its assigned flight level should, whenever possible, minimise its rate of descent while acquiring the 30 nm offset track; and for the subsequent level flight, a flight level should be selected which differs from those normally used: by 1000 ft if above FL410 or by 500 ft if below FL410.
11.3.5 Before commencing any diversion across the flow of adjacent traffic, aircraft should, whilst maintaining the 30 nm offset track, expedite climb above or descent below the vast majority of NAT traffic (i.e. to a level above FL410 or below FL285), and then maintain a flight level which differs from those normally used: by 1000 ft if above FL410, or by 500 ft if below FL410. However, if the pilot is unable or unwilling to carry out a major climb or descent, then any diversion should be carried out at a level 500 ft different from those in use within MNPS Airspace, until a new ATC clearance is obtained.
11.3.6 If these contingency procedures are employed by a twin engine aircraft as a result of the shutdown of a power unit or the failure of a primary aircraft system the pilot should advise ATC as soon as practicable of the situation, reminding ATC of the type of aircraft involved and requesting expeditious handling.
11.4 DEVIATIONS AROUND SEVERE WEATHER
11.4.1 If the aircraft is required to deviate from track to avoid weather (e.g. thunderstorms), the pilot should request a revised clearance from ATC and obtain essential traffic information, if possible prior to deviating. However, if such prior ATC clearance cannot be obtained, the procedures described below should be adopted and in the meantime efforts should be continued to obtain an appropriate ATC clearance.
a) If possible, deviate away from the organised track or route system;
b) Establish communications with and alert nearby aircraft broadcasting, at suitable intervals: aircraft identification, flight level, aircraft position (including ATS route designator or the track code) and intentions, on the frequency in use and on frequency 121.5 MHz (or, as a back-up, on the VHF inter-pilot air-to-air frequency 123.45 MHz);
c) Watch for conflicting traffic both visually and by reference to ACAS (if equipped); d) Turn on all aircraft exterior lights.
NAT MNPS 65 Edition 2005
e) For deviations of less than 10 nms, aircraft should remain at the level assigned by ATC; f) For deviations of greater than 10 nms, when the aircraft is approximately 10 nms from track,
initiate a level change of 300 ft.
- If flying generally Eastbound (i.e. a magnetic track of 000° to 179°) and deviating left (ie north) of track then descend 300 ft; if, however, deviating right (i.e. south) of track then
climb 300 ft.
- If flying generally Westbound (i.e. a magnetic track of 180° to 359°) and deviating left (i.e. south) of track then climb 300 ft; if, however, deviating right (i.e. north) of track then
descend 300 ft.
i.e.
Route centre line track Deviations>19 km (10 NM) Level change EAST (000° 179° magnetic) LEFT
RIGHT
DESCEND 90 m (300 ft) CLIMB 90 m (300 ft) WEST (180° 359° magnetic) LEFT
RIGHT
CLIMB 90 m (300 ft) DESCEND 90 m (300 ft) g) When returning to track, regain the last assigned flight level, when the aircraft is within
approximately 10 nms of centre line.
11.4.2 The pilot should inform ATC when weather deviation is no longer required, or when a weather deviation has been completed and the aircraft has returned to the centre line (or previously adopted SLOP Offset) of its cleared route.
11.5 WAKE TURBULENCE
11.5.1 Any pilot who encounters a wake turbulence incident when flying in NAT MNPS Airspace should ensure that a detailed report is provided to the NAT CMA. A suggested ‘Wake Turbulence Report Form’ for this purpose is shown at Attachment 3 to this Manual.
11.5.2 The Strategic Lateral Offset Procedure (see Chapter 8) is now a standard operating procedure throughout the NAT Region. Thus when flying within NAT MNPS Airspace, if the aircraft encounters wake turbulence and the pilot considers it necessary to offset from the current track then the pilot may only elect to fly another of the three options allowable in SLOP (i.e. Cleared Track centre-line, or 1 nm or 2 nms right of centre-line). It is no longer possible to offset left of the track centre-line to avoid wake turbulence. If neither of the remaining SLOP offset tracks are upwind of the other aircraft which is causing the wake turbulence, then the pilot should co-ordinate with the other aircraft via the inter-pilot frequency 123.45 MHz, and perhaps request that the other aircraft adopt an alternative (SLOP) allowable downwind offset.
11.6 ACAS/TCAS ALERTS AND WARNINGS
11.6.1 With effect from 01 January 2005 all turbine-engined aircraft with a certificated take-off mass exceeding 5,700 Kgs or authorised to carry more than 19 passengers are required to carry and operate ACAS II in the NAT Region.
11.6.2 The provisions relating to the carriage and use of ACAS II are contained in ICAO Annexes 2, 6, 10 & 11 and in the Procedures for Air Navigation Services (PANS) Ops & ATM. Operational procedures are fully detailed in PANS-OPS Doc 8168, Volume 1, Part VIII, Chapter 3
NAT MNPS 66 Edition 2005
11.6.3 All Resolution Advisories (RAs) should be reported to ATC:
• verbally, as soon as practicable; and
• in writing, to the Controlling Authority, after the flight has landed, using the necessary procedure and forms, including, when appropriate, the ‘Altitude Deviation Report Form’ shown at Attachment 2 to this Manual.
NAT MNPS 67 Edition 2005