Stalling at 30,000ft or above

When I fly above 30000ft in any aircraft I begin to slow down , then stall anyone have a solution 😉

4 Likes

Try to lower the Vertical Speed and increase the speed of the aircraft.

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You would only be stalling if:

Your VS is set too high.
Your speed is set too low.

Make sure your speed and VS are at the correct settings.

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  • Weight should be not too high
  • VS of max 1500
  • Autothrottle holding about 270KIAS
  • No spoilers or gear out
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You’re saying that you begin to slow down first. You’re not trying to exit the region yet right?

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Had the same issue as @Dubai_lights.
Couldn’t make the 787 to fly level on FL340 with a set speed of 290kts. Was going up and down all the time with the AP trying to increase and decrease speed at the same time. As soon as I was below FL300 everything was fine.

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Were you stable on manual?

Thanks for contacting support!

First of all, don’t worry, this is a common problem but can be easily corrected by a few adjustments to pilot technique.

We would recommend the following;

  • Reducing you vertical speed. A high vertical speed can often lead to a loss of speed and subsequently a stall at higher altitudes. Try a VS in the vicinity of 1000FPM.

  • Increase speed - After 10,000ft, try accelerating to around 270-280 (aroundabouts) knots and having the autopilot hold that speed up until cruising altitude. You may want to decrease this a little as you go higher.

  • Ensure that all flaps and speedbrakes (spoilers) are retracted.

  • Try reducing the aircraft weight

  • Ensure that you are not flying out of the regions, as that will induce a throttle cut and you will lose power.

Be sure to let us know if you are still having difficulties after following these steps.

Kind Regards,
NEO

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Make sure to check weight, put it on light setting and try to reproduce the bug please :)

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I’ve never adjusted the weight myself, so it was on the original settings. I’ll try it and get back to you. And I’ll also check the manual level flight for @Pradyut_Mandal

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The standard weight is above max landing weight if my memory serves me well

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Yeah, go ahead and check the manual flying to see if it’s an AP issue, but if you follow all of Neo’s steps above you should be good.

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You’re absolutely right with that. Adjusted it light.

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Simply step climb. And a lower V/S.

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So, I went up even further. Weight been set to “light” prior to take off. Managed to get to FL340 with 2400fpm. Then further up to FL430. Speed on AP have been adjusted accordingly. Now, flying level on FL340 with M0.81, without any issues. This was in 787-10. I’ll give the 787-9 a go as well as I can’t remember which 787 I’ve used when I had the problem but I don’t think it’s aircraft specific.

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If you have a too high vertical speed, the aircraft will stall. Some help: for an A321 I found that I begin stalling at about 7000 ft/minute. For an A380 it’s about 3500 ft/minute. I usually fly the 321 at 6000-6600 ft/minute and the 380 at 2000-2800 ft/minute.

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Oh yeah, also the ft/min I gave was a clean loadout and bout 85% throttle

That my friend is TOO MUCH VS

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It’s good fun though

Ok that is a bit too much. 4000 ft/min is more acceptable (ONLY IN A SHORT TO MEDIUM HAUL AIRCRAFT)