Random Stall Whilst Cruising?

Okay, so I was flying from Perth (YPPH), on my way to Heathrow (EGLL) on a 787-9. As I was flying over the gulf I decided to step climb from FL360 to FL380. Where then I realised before stalling that the aircraft was capable of climbing where the throttle was at 75% (I think) before climbing to FL380. When the 787 reached FL380 I had to go where I came 1:30 hours later to find my flight to have crashed… So I had discovered that when I was at FL380 I began to lose speed unknowingly. If anybody would like the replay, please let me know, I’m not sure how to send except for Share My Infinite Fight, which won’t work for me…

infiniteflight-20190728011442434.replay - Google Drive This is the link to anyone who wants to view

Are you sure you had enough fuel for your flight?

Unfortunately I’m already Taxing out of OMDB, and won’t be able to see it until I land.

Just a question, was your auto-throttle on? If so then that is weird, might be some bug.

Yeah, I had 2 hours extra fuel with me

No worries, and yes auto throttle was left on. When I stepped climbed I put 1500FPM which when I saw had given me no issue since in that climb I was using around 85-90% throttle

You need to open the link I think

I don’t need to watch it to tell that you climbed too high too soon.

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You may have a point. However, I was confident that a 787 cruising at FL360 with 75% throttle input was capable of climbing to FL380

It’s more about the N1, the green thing above the throttle input

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1500fpm might have been too steep for the step-climb

I am watching your replay now.

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That could’ve been the cause maybe

I didn’t focus on the N1

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Okay thanks

So, looking at your replay… (photos will be added shortly)

It was at this exact moment when you started dropping your speed, I have no idea why.
The 787 is known to pitch up constantly during flight, which uses lots of fuel. I believe I your case the wind/power/speed/pitch ratio was too much for the aircraft, as you were traveling West slowly pitching upwards more and more.

At 470 knots/Mach 0.80 your aircraft gave up, pitching up heavily and losing speed until at 260 knots/M0.44 where your aircraft couldn’t give any more, and started to fall to the ground from 38,000ft. This is when your aircraft began to start the deadly end.

Your aircraft took a small left turn off your FPL, and couldn’t handle it at a slow speed, which flipped it over and the AP turned off.

You also got 3 speed violations, which your lucky you didn’t get ghosted. The staff would have removed that though.

Overall I don’t know why exactly your aircraft stalled. You did have enough power and speed until shortly after Doha… I thought I’d include the crash 😂


Wow that’s incredible😂. I think like you said before I might’ve overstressed the aircraft. But other than that thanks 👍🏽😂. I’ll try and see what went wrong here

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I think it’s just the pitch in the 787 overall as you were travelling west and the wind speeds increased probably over 100knts.

Yeah. Might’ve just been bad timing from there. Although the winds at FL380 were in favour

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Honestly, I think something or someone might have deactivated your auto-throttle. I am no aviation expert, but I have Fundamentals of Flight as one of my modules as part of my course of study. Either way, I think this is just a classic stall due to lack of airspeed for sufficient lift.

I have looked at QF9 and your flight. By comparison, a climb to FL380 is expected over the Middle Eastern Area. With your airspeed at M0.84 and the actual flight also cruising at around the same ground speed, it’s safe to say that you were okay initially at FL340. Why the aircraft lost speed after the climb is the main mystery here. As far as my mind can think of, it might be because either it was manually deactivated due to an intentional or unintentional pressing of the Auto-throttle switch, or due to your disconnection from the server. Both of which triggered a series of unlikely and unfortunate coincidences which caused the stall to begin with.

If there is a stall due to Lack of airspeed to maintain directional control, it would have your wings banking left and right as a warning to you, due to your high weight.

You didn’t turn left or right at an excessive bank angle (obviously), so stall due to tight radius turn is also out of the question. (duh…)

The last and only one I can think of at the moment is stall due to lack of airspeed for sufficient lift. As mentioned earlier, your aircraft took a small left turn off the FPL and then started to spiral to the ground.

As for the timing of the winds, I don’t think that it is the reason. I mean, think about it, planes will start falling out of the skies above at your location of stall. Don’t get me wrong, I am not blaming you for anything. It just so happened that a series of unlikely coincidences occurred for some reason. I feel bad for you though, after spending qutie a while flying and then just to come back to this. :(