The ICAO cleaned up the disparate procedures for oceanic contingencies nicely about 2007, but the procedures in the North Atlantic change March 28, 2019. So what follows below are:
- Reference Guides (of the procedures in a handy two pages)
- General Procedures (for everywhere except the North Atlantic)
- North Atlantic Procedures (for the North Atlantic)
Photo: NAT Contingencies, effect 28 Mar 2019, https://ops.group/
Click photo for a larger image
[ICAO Doc 4444, ¶18.104.22.168] Although all possible contingencies cannot be covered, the procedures in 15.2.2 and 15.2.3 provide the more frequent cases such as:
- inability to comply with assigned clearance due to meteorological conditions, aircraft performance, or pressurization failure;
- en route diversion across the prevailing traffic flow; and
- loss of, or significant reduction in, the required navigation capability when operating in an airspace where the navigation performance accuracy is a prerequisite to the safe conduct of flight operations.
ICAO Doc 4444, ¶22.214.171.124] With regard to 126.96.36.199 a) and b), the procedures are applicable primarily when descent and/or turn back or diversion is required. The pilot shall take action as necessary to ensure the safety of the aircraft, and the pilot's judgment shall determine the sequence of actions to be taken, having regard to the prevailing circumstances. Air traffic control shall render all possible assistance.
Want this summarized in easy one- or two-page reference guides? The following are presented from a collaborative effort from Nat Iyengar, Guy Gribble (International Flight Resources), and Mitch Launius (30 West IP). If you are flying a G450, G550, or G650 there are specific guides. Otherwise there are general guides. You can use the PDF versions as is or customize the DOC versions. The authors emphasize that they are open-source documents from a collaborative effort over many years.
The Gulfstream versions mention that you can approximate L/DMAX by flying VREF (on our display controller) + 10 knots. They got this from pilots at Gulfstream and it seems about right. There is a debate among Gulfstream company pilots about "Normalized AOA" and using it as a flight instrument. Depending on who you talk to, a normalized AOA takes into account all sorts of factors or is nothing more than the stall angle of attack in degrees converted to 1.0 with lower values attributed to lower angles. I have taken AFM data to come up with L/DMAX = 0.30 AOA. More about that here: L/D-max. I certainly wouldn't fly slower than VREF + 10 at altitude.
Declaring an emergency is a game changer just about anywhere in the world and using "Mayday" or "Pan Pan" is the only way to change the rules of the game in some parts of the world. You shouldn't be shy about using it if you need traffic priority. I've done this eighteen times in my short life and there has never been anything negative as a result.
[ICAO Doc 4444, ¶188.8.131.52] If an aircraft is unable to continue the flight in accordance with its ATC clearance, and/or an aircraft is unable to maintain the navigation performance accuracy specified for the airspace, a revised clearance shall be obtained, whenever possible, prior to initiating any action.
[ICAO Doc 4444, ¶184.108.40.206] The radiotelephony distress signal (MAYDAY) or urgency signal (PAN PAN) preferably spoken three times shall be used as appropriate. Subsequent ATC action with respect to that aircraft shall be based on the intentions of the pilot and the overall air traffic situation.
More about this: Declaring an Emergency.
[ICAO Doc 4444, ¶220.127.116.11] If prior clearance cannot be obtained, until a revised clearance is received the following contingency procedures should be employed and the pilot shall advise air traffic control as soon as practicable, reminding them of the type of aircraft involved and the nature of the problem. In general terms, the aircraft should be flown at a flight level and on an offset track where other aircraft are least likely to be encountered. Specifically, the pilot shall:
- leave the assigned route or track by initially turning at least 45 degrees to the right or to the left, in order to acquire a same or opposite direction track offset 15 NM (28 km) from the assigned track centreline. When possible, the direction of the turn should be determined by the position of the aircraft relative to any organized route or track system. Other factors which may affect the direction of the turn are:
- the direction to an alternate airport;
- terrain clearance;
- any strategic lateral offset being flown; and
- the flight levels allocated on adjacent routes or tracks;
- having initiated the turn:
- if unable to maintain the assigned flight level, initially minimize the rate of descent to the extent that is operationally feasible (pilots should take into account the possibility that aircraft below on the same track may be flying a 1 or 2 NM strategic lateral offset procedure (SLOP)) and select a final altitude which differs from those normally used by 150 m (500 ft) if at or below FL 410, or by 300 m (1,000 ft) if above FL 410; or
- if able to maintain the assigned flight level, once the aircraft has deviated 19 km (10 NM) from the assigned track centreline, climb or descend to select a flight level which differs from those normally used by by 150 m (500 ft) if at or below FL 410, or by 300 m (1,000 ft) if above FL 410;
- establish communications with and alert nearby aircraft by broadcasting, at suitable intervals on 121.5 MHz (or, as a backup, on the inter-pilot air-to-air frequency 123.45 MHz) and where appropriate on the frequency in use: aircraft identification, flight level, position (including the ATS route designator or the track code, as appropriate) and intentions;
- maintain a watch for conflicting traffic both visually and by reference to ACAS (if equipped);
- turn on all aircraft exterior lights (commensurate with appropriate operating limitations); and
- keep the SSR transponder on at all times.
ICAO Doc 4444, ¶18.104.22.168.1] When leaving the assigned track:
- if the intention is to acquire a same direction offset track, the pilot should consider limiting the turn to a 45 degree heading change, in order not to overshoot the offset contingency track; or
- if the intention is to acquire and maintain an opposite direction offset track, then:
- operational limitations on bank angles at cruising altitudes will normally result in overshooting the track to be acquired. In such cases a continuous turn should be extended beyond 180 degrees heading change, in order to re-intercept the offset contingency track as soon as operationally feasible; and
- furthermore, if executing such a turn back in a 56 km (30 NM) lateral separation route structure, extreme caution pertaining to opposite direction traffic on adjacent routes must be exercised and any climb or descent, as specified in 22.214.171.124 b) 2), should be completed preferably before approaching within 19 km (10 NM) of any adjacent ATS route.
North Atlantic Procedures
There can be no doubt, the airspace in the North Atlantic is the most densely packed oceanic airspace in the world. The tracks are tighter and the longitudinal spacing is reduced. It only makes sense that contingency procedures have to consider all that. Starting March 28, 2019, you will have these procedures to remember.
[NAT OPS Bulletin 2018-005, ¶1.1] These procedures are applicable in the NAT Region 29th of March 2019, coincident with the trial of Advanced Surveillance-Enhanced Procedural Separation (ASEPS) using Automatic Dependent Surveillance-Broadcast (ADS-B) in the Shanwick, Gander and Santa Maria Oceanic Control Areas, and will subsequently replace those currently published in the PANS ATM (ICAO Doc 4444).
Photo: Contingency Procedures, NAT OPS Bulletin 2018-005, figure 1.
Click photo for a larger image
[NAT OPS Bulletin 2018-005] 2. General Procedures
Note.— Figure 1 provides an aid for understanding and applying the contingency procedures contained in paragraphs 2 and 3.
2.1 If an aircraft is unable to continue the flight in accordance with its ATC clearance, a revised clearance shall be obtained, whenever possible, prior to initiating any action.
2.2 If prior clearance cannot be obtained, the following contingency procedures should be employed until a revised clearance is received:
a) leave the cleared route or track by initially turning at least 30 degrees to the right or to the left, in order to intercept and maintain a parallel, direction track or route offset 9.3 km (5.0 NM). The direction of the turn should be based on one or more of the following:
1) aircraft position relative to any organized track or route system,
2) the direction of flights and flight levels allocated on adjacent tracks,
3) the direction to an alternate airport;
4) any strategic lateral offset being flown, and
5) terrain clearance;
b) the aircraft should be flown at a flight level and an offset track where other aircraft are less likely to be encountered.
c) maintain a watch for conflicting traffic both visually and by reference to ACAS (if equipped) leaving ACAS in RA mode at all times, unless aircraft operating limitations dictate otherwise;
d) turn on all aircraft exterior lights (commensurate with appropriate operating limitations);
e) keep the SSR transponder on at all times and, when able, squawk 7700, as appropriate;
f) as soon as practicable, the pilot shall advise air traffic control of any deviation from assigned clearance;
g) use whatever means is appropriate (i.e. voice and/or CPDLC) to communicate during a contingency or emergency;
h) if voice communication is used, the radiotelephony distress signal (MAYDAY) or urgency signal (PAN PAN) preferably spoken three times, shall be used, as appropriate;
i) when emergency situations are communicated via CPDLC, the controller may respond via CPDLC. However, the controller may also attempt to make voice communication contact with the aircraft;
Note.— Additional guidance on emergency procedures for controllers, radio operators, and flight crew in data link operations can be found in the Global Operational Data Link (GOLD) Manual (Doc 10037).
j) establish communications with and alert nearby aircraft by broadcasting, at suitable intervals on 121.5 MHz (or, as a backup, on the inter-pilot air-to-air frequency 123.45 MHz) and where appropriate on the frequency in use: aircraft identification, the nature of the distress condition, intention of the person in command, position (including the ATS route designator or the track code, as appropriate) and flight level; and
k) the controller should attempt to determine the nature of the emergency and ascertain any assistance that may be required. Subsequent ATC action with respect to that aircraft shall be based on the intentions of the pilot and overall traffic situation.
[NAT OPS Bulletin 2018-005] 3. Actions to be taken once offset from track.
Note. — The pilot’s judgment of the situation and the need to ensure the safety of the aircraft will determine whether the actions outlined in 3.2 a) or b), will be taken. Factors for the pilot to consider when diverting from the cleared route or track without an ATC clearance include, but are not limited to:
a) operation within a parallel track system,
b the potential for User Preferred Routes (UPRs) parallel to the aircraft’s track or route,
c) the nature of the contingency (e.g. aircraft system malfunction) and
d) weather factors (e.g. convective weather at lower flight levels).
3.1 If possible maintain the assigned flight level until established on the 9.3 km (5.0 NM) parallel, same direction track or route offset. If unable, initially minimize the rate of descent to the extent that is operationally feasible.
3.2 Once established on a parallel, same direction track or route offset by 9.3 km (5.0 NM), either:
a) descend below FL 290, and establish a 150 m (500 ft) vertical offset from those flight levels normally used, and proceed as required by the operational situation or if an ATC clearance has been obtained, proceed in accordance with the clearance; or
Note. — Descent below FL 290 is considered particularly applicable to operations where there is a predominant traffic flow (e.g. east-west) or parallel track system where the aircraft’s diversion path will likely cross adjacent tracks or routes. A descent below FL 290 can decrease the likelihood of: conflict with other aircraft, ACAS RA events and delays in obtaining a revised ATC clearance.
b) establish a 150 m (500 ft) vertical offset (or 300 m (1000 ft) vertical offset if above FL 410) from those flight levels normally used, and proceed as required by the operational situation, or if an ATC clearance has been obtained, proceed in accordance with the clearance.
Note. — Altimetry System Error may lead to less than actual 500 ft vertical separation when the above procedure is applied. In addition, with the 500 ft vertical offset applied, ACAS RAs may occur.
[NAT OPS Bulletin 2018-005] 4. Weather deviation procedures
Note.— The following procedures are intended for deviations around adverse meteorological conditions.
4.1.1 When weather deviation is required, the pilot should initiate communications with ATC via voice or CPDLC. A rapid response may be obtained by either:
a) stating “WEATHER DEVIATION REQUIRED” to indicate that priority is desired on the frequency and for ATC response; or
b) requesting a weather deviation using a CPDLC lateral downlink message.
4.1.2 When necessary, the pilot should initiate the communications using the urgency call “PAN PAN” (preferably spoken three times) or by using a CPDLC urgency downlink message.
4.1.3 The pilot shall inform ATC when weather deviation is no longer required, or when a weather deviation has been completed and the aircraft has returned to its cleared route.
4.2 ACTIONS TO BE TAKEN WHEN CONTROLLER-PILOT COMMUNICATIONS ARE ESTABLISHED
4.2.1 The pilot should notify ATC and request clearance to deviate from track or route, advising, when possible, the extent of the deviation requested. The flight crew will use whatever means is appropriate (i.e. voice and/or CPDLC) to communicate during a weather deviation.
Note.— Pilots are advised to contact ATC as soon as possible with requests for clearance in order to provide time for the request to be assessed and acted upon.
4.2.2 ATC should take one of the following actions:
a) when appropriate separation can be applied, issue clearance to deviate from track; or
b) if there is conflicting traffic and ATC is unable to establish appropriate separation, ATC shall:
1) advise the pilot of inability to issue clearance for the requested deviation;
2) advise the pilot of conflicting traffic; and
3) request the pilot’s intentions.
4.2.3 The pilot should take the following actions:
a) comply with the ATC clearance issued; or
b) advise ATC of intentions and execute the procedures detailed in paragraph 4.3.
4.3 ACTIONS TO BE TAKEN IF A REVISED ATC CLEARANCE CANNOT BE OBTAINED
Note.— The provisions of this section apply to situations where a pilot needs to exercise the authority of a pilot-in-command under the provisions of Annex 2, 2.3.1.
4.3.1 If the aircraft is required to deviate from track or route to avoid adverse meteorological conditions and prior clearance cannot be obtained, an ATC clearance shall be obtained at the earliest possible time. Until an ATC clearance is received, the pilot shall take the following actions:
a) if possible, deviate away from an organized track or route system;
b) establish communications with and alert nearby aircraft by broadcasting, at suitable intervals: aircraft identification, flight level, position (including ATS route designator or the track code) and intentions, on the frequency in use and on 121.5MHz (or, as a backup, on the inter-pilot air-to-air frequency 123.45MHz);
c) watch for conflicting traffic both visually and by reference to ACAS (if equipped);
d) turn on all aircraft exterior lights (commensurate with appropriate operating limitations);
e) for deviations of less than 9.3 km (5.0 NM) from the originally cleared track or route remain at a level assigned by ATC;
f) for deviations greater than or equal to 9.3 km (5.0 NM) from the originally cleared track or route, when the aircraft is approximately 9.3 km (5.0 NM) from track, initiate a level change in accordance with Table 15-1;
g) if the pilot receives clearance to deviate from cleared track or route for a specified distance and, subsequently, requests, but cannot obtain a clearance to deviate beyond that distance, the pilot should apply an altitude offset in accordance with Table 1 before deviating beyond the cleared distance.
h) when returning to track or route, be at its assigned flight level when the aircraft is within approximately 9.3 km (5.0 NM) of the centre line; and
i) if contact was not established prior to deviating, continue to attempt to contact ATC to obtain a clearance. If contact was established, continue to keep ATC advised of intentions and obtain essential traffic information.
Note.— If, as a result of actions taken under the provisions of 4.3.1, the pilot determines that there is another aircraft at or near the same flight level with which a conflict may occur, then the pilot is expected to adjust the path of the aircraft, as necessary, to avoid conflict.
Photo: Deviation level change, NAT OPS Bulletin 2018-005, table 1.
Click photo for a larger image
North Atlantic Exception for 180° Turn back
You may find exceptions to the ICAO procedures here and there. Perhaps most notable of these is the North Atlantic procedure for a 180° turn back The ICAO advises that you execute a "continuous 180° turn" beyond 180° so as to acquire and maintain the proper offset. The NAT procedure is to maintain a "same direction" offset until completing a climb or descent before making the turn.
[NAT Doc 007, ¶13.3.5] Before commencing any diversion across the flow of adjacent traffic or before initiating any turn-back (180°), aircraft should, while subsequently maintaining a same direction 15 NM offset track, expedite climb above or descent below the vast majority of NAT traffic (i.e. to a level above FL410 or below FL280), 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 or turn-back manoeuvre should be carried out
Letter to Eddie
See that contact button on the bottom and top of the page? (It's so important it appears twice!) I do answer my mail.
Your latest oceanic contingencies article got me to thinking more about the process. Essentially one is supposed to turn off the track and slow to drift down speed and continue in the same direction until descending below FL290 before making the turn back to your alternate.
I dug into the flight manual performance section regarding single engine procedures. Average numbers for our plane at weights and altitude near the single engine ETP point: 220 IAS, 380 TAS and a 300 fpm descent rate. Assuming no wind and starting from FL350, it would take about 22 minutes and 140 NM to get below 290. Then another 22 minutes not including the turn to get abeam the point at which the engine failed in the first place. Roughly 45 minutes spent before making headway to your landing. This seems counter intuitive and I was hoping for your insight.
Signed, R. Fader
Fort Lee, New Jersey
Dear Mister Fader,
It is counterintuitive in many more ways than just the safety of your airplane. In the North Atlantic, especially, you have the safety of everyone around you to worry about. In the days before the skies became so crowded, the answer was to indeed drift down according to your aircraft’s best ability so as to milk every last forward mile possible. But these days, doing that could endanger other airplanes. Is it morally right to endanger an airliner filled with hundreds of people to improve the odds for the ten or so sitting behind your cockpit? But we do have greater communications and surveillance as well as TCAS to help out.
So, all that being said, here is my plan. I try to allow for enough fuel to keep a proper offset until above or below the tracks. If it happens, I’ll be communicating with the air traffic service unit and trying to get the best drift down I can, but I won’t do that unless I have clearance. This means you cannot be content with having just enough ETP fuel to make your destination. Here is some food for thought: The Great Escape.
Portions of this page can be found in the book International Flight Operations, Part VI, Chapter 1.
ICAO Doc 4444 - Air Traffic Management, 16th Edition, Procedures for Air Navigation Services, International Civil Aviation Organization, October 2016
NAT Doc 006 Part I - ATM Contingency Plan, Amendment 11, July 2018, Published on behalf of the North Atlantic Systems Planning Group (NAT SPG) by the European and North Atlantic Office of ICAO
NAT Doc 007, North Atlantic Operations and Airspace Manual, v 2018-1
NAT OPS Bulletin 2018-05, Special Procedures for In-flight Contingencies in Oceanic Airspace, 17 Dec 2018