Posts by user "Mrshed" [Posts: 56 Total up-votes: 0 Pages: 3]

I'd assume that the prelim wouldnt (surely?) call out the gear down item explicitly and not reference a command for gear up if it existed - but could be wrong. For me your former suggestion is more likely I think.

Incidentally, on the topic of lever positions in the wreckage, anyone find the thrust position at idle in the wreckage (at odds with the data) of interest? My assumption is this must have happened post impact, but it's a (small) oddity.

What we don't know, but agree is implied in the report, is whether this was said before they were flipped back on.

It's possible from the timeline in the report that this statement was made at the same time (or even after) they were moved back to RUN. The report is ambiguous on this unfortunately...!

Re: spool down to idle, that is interesting and passed me by - the report certainly does imply it took 5 seconds, which is at odds at an earlier post from (I believe) tdracer , who said this would take 1, maximum 2, seconds.

However when I read it again, it's again ambiguous - the 5 seconds is when the RAT started supplying power, but this isn't clear and unequivocal that engine went below idle at the same time in the wording, although definitely heavily implied.

These for me are very interesting questions.

There seems to be a period around second 12/13 post V1 where engines are (or should) be likely below idle, but prior to RAT power generation.

Note that the report explicitly states the RAT started providing hydraulic power 5 seconds after engine shutdown commenced. It doesn't reference electrical power. So we don't know whether this was at the same time - others may clarify re: RAT operation.

But either way, it would appear there would be a gap in power (which, incidentally, would tie in with the survivor commentary). But yet ADS data continued.

If in fact there was a momentary loss of power then that would contribute heavily to the startle and "delay" in refiring (although comments here make me think there wasn't really such a delay anyway).

(And incidentally would make what appears to be a really rather valiant attempt to save the aircraft even more impressive)

Thanks - apologies for the stupid follow on question but the report notes that the APU inlet door started to open approx 8 seconds after RAT started to generate hydraulic power.

I assume this means that the APU was not operational until this point?

Thanks to you both.

So this brings me back to my original observation (and that of another poster) - it would appear that there was a time period of at least 2 seconds, and potentially longer depending upon RAT electrical power, where the aircraft lost some (?) or all (?) electrical power, which hasn't really been discussed.

This would definitely contribute to recovery challenges (albeit slightly tangential to root cause discussion).

(And, strangely, ADS data appeared to continue during the period this would have occurred)

Incidentally, the APU door started opening *after* the initiation of relight of the first engine.

Without the APU, would there have been sufficient power to restart even one engine, never mind two?

Could this be why the delay between the first and second switches being moved to RUN?

Does it also mean that in reality the 10 seconds between OFF and RUN is immaterial as there was insufficient electrical power to start the engines anyway?

Because it wouldnt have been immediately available to support engine restart and/or other electrical functions, as it didn't open until around 13 seconds after cutoff event. It's relevant in so much of how it may (or may not) have affected recovery efforts.

It was working as per the conditions absolutely, but those conditions meant it wasn't available immediately.

I hardly think that the single sole relevant learning from an event such as this, and hence the sole discussion point, is around the trigger of the event. Yes, very relevant, but plenty of other areas to understand further as well (for example how a dual engine failure at such altitude could be adjusted in future process). If you aren't interested in that discussion that's ok of course, but it doesn't make it irrelevant.

That's not the question.

The question is what impact was had on attempts to recover the aircraft by the (presumed) lack of most or all electrical power.

As the main instigator of that discussion I can tell you you got that right 👍

Thanks for confirming - the point I'm trying to make (apparently badly) is the lack of APU until at least 12-13 seconds after loss of engines, lack of electrical power from the engines, and at best limited electrical power from the RAT (and for a time, none), would have affected other systems used by the pilots during this short flight, at least for part of it. This hasn't been discussed basically at all, despite a lot of discussion around the ten second delay to start the engines restart, even though that power loss would have been in that window.

Thank you - this (I think) really clarifies for me. And apologies for bringing confusion (definitely my doing), but appreciate the clarification 😊

I largely agree.

What I'm trying to understand is whether this situation contributed to startle, and goes part of the way to explaining the 10 seconds delay between CUTOFF and RUN that some are discussing. That's it really.

FWIW, moving the ADS data 4 seconds is potentially plausible, but it would mean the max reported altitude is extremely early in the flight, probably too early.

That's interesting and potentially tightens the time window a little (if one presumes that the valve position is a proxy of switch position, which in this case there's no reason to believe otherwise, and if the prelim uses this info to feed it's timestamps which I'd loosely assume it probably does...).

I don't think a ten second gap between event and recovery action is particularly noteworthy in terms of demonstrating malfeasance.

Bear in mind that it would take 1 to 2 seconds for this to have become fully apparent, plus then initial surprise to figure out it was engine related - being optimistic, 3 seconds total.

7 seconds does not seem remotely unreasonable to then deduce cause, especially given what various other posters have said that FC switches wouldn't be high on their list to check. In fact, it seems like pretty good going.

If it was 10 seconds between the CVR and recovery action (as per your quoted poster) then that changes things quite a bit. But it wasn't.

PS the conclusion may be right (or it may not be), I'm open on the topic. But that 10 seconds gap doesn't tell us the answer.

The problem is that that is fitting the facts to the narrative, not the other way round.

Truth is that the 10 sec delay is consistent with that, but it's also wholly consistent with it being accidental.

It is effectively irrelevant in the deduction.

If the CVR discussion is very early in the 10 seconds, then that consistency changes...but we don't know that.

I have zero view for or against cameras on flight deck. However, there is one obvious (to me) reason they would reduce at least some of these events.

Often, those committing suicide do not want it known that it was in fact suicide, as this has tangible harms for their family (financial and reputational). Cameras on flight deck would generally provide confirmative evidence of intent, and as such if family was a factor in this way, this would likely cause at least pause for thought for someone with these intentions.

There's other ways I would say that it would reduce (albeit not per incident) such as the general aviation trend of implementing improvements/mitigations from observed events - cant say what these may be, basically by definition.

Got no view but I think there are at least some factors which would likely cause a reduction (or, minimally, plausibly could).

Re: MH370 - that calls for hindsight not known at the time (assuming it was suicide which we obviously dont know).

I.e. knowledge that the boxes wouldnt be recovered.

I don't think the intention in your quoted post is to suggest there should be an AD - more a "come on, it's obvious" statement I think.

I think anyone still positioning a possibility other than physical movement of the switches at this point needs to bear in mind the following.

- The investigators and authors of the preliminary report clearly have more information than has been released in that report, a lot more. This includes, as per the report, the full recorded audio of the flight.
- With that additional information comes a greater ability to rule in or out certain possibilities, if we presume competence (which we clearly should).
- With all of that additional information and knowledge, *all* of the involved parties have explicitly stated there are no recommended actions regarding the airplane. This would be a pretty low threshold to issue even a precautionary advisory to check x,y,z if it was still deemed a possible cause.

It is reasonable to say, I would say, that the investigators have largely ruled out the switches themselves or the electronics around them as a cause here. They are as aware as anyone on this forum of previous SAIB relating to these switches, and explicitly reference them in the report, and haven't even taken the incredibly easy step of "re-suggesting" this. This is telling and should be very carefully considered before further suggestions in this direction.

I'd then suggest that everyone else also bears in mind the following. The investigators, with the information they have, have decided not to share some of that information. In my view, there are two likely reasons for this (combined):

1. They do not believe that releasing that information provides any additional safety benefit at this time *to other aircraft*.
2. The likely cause (or options of likely causes) demands exhaustive investigation to further check what the investigation is pointing to to date, and be positive of the cause to the highest possible threshold before even implying it. It may be frustrating that this leaves ambiguity, but this ambiguity is likely both intentional and necessary.

In my mind, this alone (but especially when taken in conjunction with other evidence) likely rules out the option of an object causing the movement in the switches. It also probably rules out an incorrectly followed procedure as this again would likely be fed out.

This really only leaves two options - completely erroneous action taken by a pilot (completely abnormal in its nature), or deliberate action taken by a pilot. Either of these demands full validation prior to concluding them publicly. The investigators, like us, probably have their views already on which is more likely (especially given the full CVR).

The preliminary report, as has been said, is actually more detailed than normal, but there are, as others have said, some interesting omissions. When you think about what the purpose of the preliminary report is, and what the objectives are of those authoring it, looking at why certain information is there (and why some isnt), combined with what they are suggesting as next steps, it does in fact tell us almost all of the story here in my view, in terms of the overall picture (not the low level detail).

Which doesn't mean the investigation may not ultimately take a different path - this is why they explore every possible avenue.