Guidance concerning Air Navigation in and above the NAT MNPSA
CHAPTER 12: SPECIAL PROCEDURES FOR IN-FLIGHT CONTINGENCIES
Situations can be anticipated in which the provision of Air Traffic Management to flights
within the NAT Region might be affected. NAT ATS Providers have developed arrangements which would, in such events, be put in place to ensure, as far as possible, the continued safety of air navigation. These arrangements include required contingency actions by pilots and operators of any affected flights. They are detailed in “The North Atlantic Air Traffic Management Operational Contingency Plan – Doc.006” which can be downloaded from the ICAO Paris website at http://www.paris.icao.int/. See Chapter 6 - Para 6.7 for further details.
However, circumstances can also occur which affect individual aircraft. The remainder of
this Chapter details guidance to pilots on contingency actions to follow to protect the safety of the flight in
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
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.
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.
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 CPDLC, station-to-station SATCOM Voice and SELCAL with HF communications in North Atlantic operations, pilots' situation awareness, of other potentially conflicting traffic, may be non-existent or incomplete. If, however, the aircraft is in an area where ATC communications are being conducted on VHF, pending receipt of any reclearance, the position and intentions should be broadcast on the current control frequency, rather than
Until a revised clearance is obtained the specified NAT in-flight contingency procedures
should be carefully followed. Procedures for general use in Oceanic airspace are contained within the ICAO PANS ATM (Doc. 4444), specifically Amendment 2 effective November 2009. Procedures particular to the NAT MNPSA environment are contained in ICAO NAT Regional Supplementary Procedures (Doc.7030) and appropriate NAT Provider States’ AIPs. The procedures are paraphrased below.
NAT Doc 007