Oceanic (Non HLA) contingency procedures

[Bert Stiles]

Any oceanic expert dudes care to comment?

Does the 45 degree / 15 nm / start action at 10 nm, general oceanic contingency offset principle apply to random tracking in oceanic airspace - in low to mid level bands - FL060 to FL280?

I ask the question because I have to write a manual and have seen other operator material, but not Authority information, to the effect that standard contingency actions do not apply as follows:

ICAO Doc 4444 subsection 15.2.2.3 a) gives the general contingency procedure (assuming no other clearance). This would seem to be universal in oceanic airspace in that it requires the aircraft to "leave its route or track". This general principle makes sense in the the vicinity of OTSs like PACOTS, NOPAC, WATRS etc, plus busier parts of the Indian and Pacific Oceans.

The NAT HLA is obviously different with its ICAO Doc 007 NAT Operations and Airspace Manual subsection 13.2 principles (30 degree turn / 5 nm offset).

However, ICAO Doc 007 NAT Operations and Airspace Manual Section 17 also covers operation below the NAT HLA and subsection 17.14 (contingencies) does not specify application of any offset manoeuvres. ICAO Doc 7030 NAT Supplementary procedures is likewise silent on specific contingency actions.

However, other support for the general procedure to apply (regardless that, for example, a specific random tracking flight at FL 260 may be the only flight at that level, in that vicinity, in that week or month) can be found in FAA notams e.g, where the NAT HLA procedure is referenced as being adopted outside of the AIP but there are notes to the effect that the general procedure still applies in Anchorage, Oakland Oceanic airspace "in their entirety" etc. This also seems to be the intent (though not stated) of FAA AC91-70B and US AIP ENR 7.3.

From personal experience when random tracking over the North Atlantic in the high teens and low twenties well below MNPSA as it was then, I didn't consider doing the specific offset but over the Pacific between Korea and Alaska at RVSM levels I did. Some manuals are better than others. Sorry if this contravenes the don't ask boring questions on the Forum Philosphy sticky.

Bert.

[Bert Stiles]

If anyone is interested I had this reply from the ICAO Paris office. Largely as expected but now confirmed.

"Regarding contingency procedures, there are no specific off set procedures for traffic at low levels. And although even for ATC, it´s the only procedures that we are aware and may be expecting from crews, the procedures on Ch 13 were set for the more congested airspace, like the OTS, and not for airspace below the HLA. The pilot or flight crew will make the best decision based on the situation they are at, and will probably not apply them if they are flying alone in the airspace. If they happen to have traffic below or in close proximity, than the answer might be different. But in any case, the action taken might be the natural response to the position of the other aircraft and not the application per se of the contingency procedures.



Regarding SLOP, and as it´s correctly mentioned, it applies to all levels in the NAT. Although it may seem irrelevant for traffic at those levels, and they always have the option of flying in track, it´s not uncommon for traffic to cross occasionally or fly in close proximity, even at low levels. When that happens, it might help to apply SLOP. It´s a recommended safety feature that a lot of times is not applied as it was intended. Some operators decide that their fleet will apply a 1NM SLOP, regardless of traffic situation, when the intent is to distribute traffic as much as possible, and have pilots, for example, make a 2NM SLOP if they are close to traffic applying a 1NM or a 0 NM SLOP. So even though it might be less used at low levels, the possibility to apply it at all levels is there for pilot consideration."

Bert.