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CHAPTER 13 - 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:

They are applicable primarily when rapid descent, turn-back, or diversion to an alternate aerodrome is required. The pilot's judgment will determine the specific sequence of actions taken, having regard to the prevailing circumstances.

GENERAL PROCEDURES

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, MAYDAY, MAYDAY) signal or urgency (PAN PAN, PAN PAN, PAN PAN) signal as appropriate.

For SATCOM equipped aircraft, in the event that all other means of communication have failed, emergency satellite voice transmissions may be made to the controlling ATC unit. In addition, allocated airborne numbers to be used only in emergency situations (excluding communications failure), are listed in appropriate AIPs. To prepare for this unlikely eventuality, consideration should be given by pilots to pre-programming any possible required numbers into the flight deck voice unit prior to entry into the NAT Region.

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 131.8 MHz as a back-up frequency).

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) and appropriate NAT Provider States’ AIPs and are paraphrased below.

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.
 

SPECIAL PROCEDURES

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.
 

Initial Action

The aircraft should leave its assigned route or track by initially turning 90 to the right or left whenever this is possible. The direction of the turn should, where possible, be determined by the position of the aircraft relative to any organized 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 and levels allocated on adjacent routes or tracks.
 

Subsequent Action

An aircraft that is able to maintain its assigned flight level should, once established on the offset track:

An aircraft that is unable to maintain its assigned flight level should, whenever possible, minimize 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.

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.

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.
 

WAKE TURBULENCE

Any pilot who encounters a wake turbulence incident when flying in NAT MNPS Airspace or within an adjacent RVSM transition area 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.

When flying within NAT MNPS Airspace (but not in adjacent domestic airspace RVSM transition areas), if considered necessary, the pilot may offset from cleared track by up to a maximum of 2 nm (upwind) in order to alleviate the effects of wake turbulence. ATC should be advised of this action and the aircraft should be returned to cleared track as soon as the situation allows. It must be noted, however, that such a maneuver is considered a contingency procedure and ATC will not issue a clearance for any such lateral offset.
 

TCAS ALERTS AND WARNINGS

In the event that a Traffic Advisory (TA) is issued, commencement of a visual search for the threat aircraft should be carried out and preparation made to respond to a Resolution Advisory (RA), if one should follow. In the event that an RA is issued, the required maneuver should be initiated immediately, subsequently adjusting power and trim. Note that maneuvers should never be made in a direction opposite to those required by the RA, and that RAs should be disregarded only when the potentially conflicting traffic has been positively identified and it is evident that no deviation from the current flight path is needed. All RAs should be reported to ATC:

Pilots should be aware that under certain conditions in NAT RVSM airspace, TCAS equipment utilizing Version 6.04a Logic (current at the date of publication of this Document) can issue nuisance Traffic Advisories relating to another aircraft which is following the same track but is correctly separated vertically by 1,000 ft above or below. Such TAs will normally be issued when the two aircraft are separated horizontally by 1.2 nm, this being the approach criterion used in the 6.04a Version Logic. It is expected that Logic Version 7, anticipated to be available in 1999, will correct this anomaly and eliminate such nuisance TAs.

(C) HANKE-Aviation GmbH 2014