Lost comms and quadrantal rule

[C_Star]

Hi guys,

Here's a scenario that caught me off guard the other day:

I was flying southbound accross Southeast Asia. We entered Manila FIR and were instructed to contact them on HF. As it happens, we were not able raise the ATC on any of the frequencies (we also tried VHF and relay, to no avail). So far, so good, happens all the time on HF...

However, as we flew deeper into the FIR, we approached a waypoint where we'd change course from westerly to easterly and, as per the flight plan, were supposed to change altitude from even to odd FL. However, we still had no contact with ATC. In this case, should we:

a) keep last cleared level against the quadrantal rule
b) change the FL immediately
c) initiate the lost comms procedure, i.e. keep the previous FL for 20 minutes since FIR entry (last failed reporting point), then change to odd level as per the FPL...

I was leaning towards c), but wasn't sure. Fortunately we were finally able to establish contact on VHF before reaching the point and the problem sorted itself out. I would, however, appreciate any input on the proper way of sorting this.

Also, as a follow-up question. Since HF is notoriously unreliable, how do you deal with no contact? Under what circumstances would you initiate a full-blown lost comm procedure?

Cheers

[KRviator]

ISTR a similar scenario was raised as part of the Brazillian mid air a while ago, whereby the flight plan called for an altitude adjustment at a waypoint, but because the crew were out of contact, remained at their previous altitude, and this was later found to be the correct course of action in the absence of any further communication or clearance from ATC.

[flyingmed]

It should be treated as a loss of comms. Follow the local ATC procedures, normally level for few minutes and then change level. Might be a good choice to squak lost comms just incase you end up with a fighter on your wing.

[hikoushi]

Most states' lost comm procedures more or less say to maintain the higher of either cleared altitude, altitude to be expected, when expected (when given by a clearance e.g. "maintain FL200 expect FL230 in 10 minutes"), or the MEA / minimum instrument altitude for the route segment. Changing altitude to abide by hemispherical rules, and changing altitude to follow a flight plan when you have not previously been actually CLEARED to that altitude, are not part of it in most cases.

[esreverlluf]

This thread scares me! That people would even think of changing cruise level without a clearance beggars belief. That area is notorious for "patchy" comms and if people are going to take it on themselves to change levels, then it's just asking for trouble.

[A Squared]

This thread scares me! That people would even think of changing cruise level without a clearance beggars belief. That area is notorious for "patchy" comms and if people are going to take it on themselves to change levels, then it's just asking for trouble.

As noted by the second poster in this thread, that was precisely the accusation inf the mid-air collision in Brasil of the Embraer biz-jet and the 737, that the biz jet was at fault for *not* changing FL after after a course change while not in Communication. Granted, the Brasilian ATC was in finger-pointing mode ...but still, the accusation was made officially.

[esreverlluf]

I think the issue in this case is that there is often a delay in establishing comms with Manila. When does a delay in establishing comms become "Lost Comms"? This is not a radio failure scenario and I would certainly be trying all other avenues of communications incl satcom before initiating my own level change.

[oggers]

I was leaning towards c), but wasn't sure.

The procedure for the Philipinnes is not the standard ICAO. It is the same as FAA:

each pilot shall continue the flight according to the following:

(2) Altitude. At the highest of the following altitudes or flight levels for the route segment being flown:

(i) The altitude or flight level assigned in the last ATC clearance received;

(ii) The minimum altitude (converted, if appropriate, to minimum flight level as prescribed in §91.121(c)) for IFR operations; or

(iii) The altitude or flight level ATC has advised may be expected in a further clearance.

Therefore, in the scenario given the correct answer is to maintain the assigned level, or minimum IFR altitude if higher.

Also, as a follow-up question. Since HF is notoriously unreliable, how do you deal with no contact? Under what circumstances would you initiate a full-blown lost comm procedure?


Good question but I would say it is something of a moot point. You will be trying to establish comms by all available means. You will either establish comms before you reach a point where you need to make a level or course change - in which case you will continue in accordance with lost comms procedure - or you'll get comms back before that happens.