World Air Ops | NAT | Doc 007 MNPS Guidance

Guidance concerning Air Navigation in and above the NAT MNPSA CHAPTER 12CHAPTER 12: SPECIAL PROCEDURES FOR IN-FLIGHT CONTINGENCIES12.1 INTRODUCTION12.1.1 Situations can be anticipated in which the provision of Air Traffic Management to flightswithin 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. Thesearrangements include required contingency actions by pilots and operators of any affected flights. They aredetailed in “The North Atlantic Air Traffic Management Operational Contingency Plan – Doc.006” whichcan be downloaded from the ICAO Paris website at http://www.paris.icao.int/. See Chapter 6 - Para 6.7 forfurther details.12.1.2 However, circumstances can also occur which affect individual aircraft. The remainder ofthis Chapter details guidance to pilots on contingency actions to follow to protect the safety of the flight insuch circumstances.12.1.3 The following procedures are intended for guidance only. Although all possiblecontingencies cannot be covered, they provide for such cases as:a) inability to maintain assigned level due to weather (for example severe turbulence);b) aircraft performance problems; orc) pressurisation failure.12.1.4 They are applicable primarily when rapid descent, turn-back, or diversion to an alternateaerodrome is required. The pilot's judgement will determine the specific sequence of actions taken, havingregard to the prevailing circumstances.12.2 GENERAL PROCEDURES12.2.1 If an aircraft is unable to continue its flight in accordance with its ATC clearance, a revisedclearance should be obtained whenever possible, prior to initiating any action, using the radio telephonydistress (MAYDAY) signal or urgency (PAN PAN) signal as appropriate.12.2.2 If prior clearance cannot be obtained, an ATC clearance should be obtained at the earliestpossible time and, in the meantime, the aircraft should broadcast its position (including the ATS Routedesignator or the Track Code as appropriate) and its intentions, at frequent intervals on 121.5 MHz (with123.45 MHz as a back-up frequency). It must be recognised that due to the use of CPDLC, station-to-stationSATCOM Voice and SELCAL with HF communications in North Atlantic operations, pilots' situationawareness, of other potentially conflicting traffic, may be non-existent or incomplete. If, however, theaircraft is in an area where ATC communications are being conducted on VHF, pending receipt of anyreclearance, the position and intentions should be broadcast on the current control frequency, rather than123.45 MHz.12.2.3 Until a revised clearance is obtained the specified NAT in-flight contingency proceduresshould be carefully followed. Procedures for general use in Oceanic airspace are contained within the ICAOPANS ATM (Doc. 4444), specifically Amendment 2 effective November 2009. Procedures particular to theNAT 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 77 Edition 2010