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Southern Air 777 stall and recovery after takeoff, Nov 15th

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Southern Air 777 stall and recovery after takeoff, Nov 15th

Old 21st Nov 2020, 04:43
  #21 (permalink)  
 
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It might show up on the flight data monitor so best to own up rather than get pulled in by the safety department. Recovering with a 750í height loss isnít too bad but obviously being close to the ground they couldnít afford a massive drop. An early recognition and prompt recovery action probably helped.

Simulator stall training often involves the fully developed case at higher altitudes where the height loss is significant and the time involved lengthy before the aircraft unstalls. More emphasis on recovery from low altitude events minimising height loss may be called for.
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Old 21st Nov 2020, 05:00
  #22 (permalink)  
 
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Alway be really careful in ALT ACQ mode with autopilot engaged.
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Old 21st Nov 2020, 05:09
  #23 (permalink)  
 
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Nike is correct if the AC captures early, speed can decay rapidly after early ALT capture ,only solution is to hit ALT HOLD wait for the nose to drop then engage VS when a more sensible ROC is indicated. It’s a particular issues on freighters at light weight with low initial departure altitude. Or they have entered an incorrect ZFW in the FMC.
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Old 21st Nov 2020, 08:30
  #24 (permalink)  
 
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The autopilot and authothrottle on Boeing aircraft has always been a dog and not worthy of being trusted. Even on the latest machines. That's why Boeing pilots are a more vigilant and twitchy bunch.

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Old 21st Nov 2020, 08:46
  #25 (permalink)  
 
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allaru

Why not klick klick, klick klick??? Drop down a level of automation or all? fly it stabilise it and then try again...
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Old 21st Nov 2020, 09:06
  #26 (permalink)  
 
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With the power of open information, comes great responsibility.

This thread, this incident, wether accurate or not, together with similar discussions based on 'open information', challenge fundamental aspects of our profession and flight safety.
Many countries protect the rights of crews with confidentiality of data, FDR / CVR which enables professional investigation and review. Yet with advancing technology and communication, accidents and incidents are now exposed to extremes of human behaviour with biased, inaccurate, and possibly deliberate misleading discussions of unvalidated data.

What hope for a just culture, reasoned judgement, peer review.

These are a fact of modern life, but safety still requires thoughtful and considered behaviour in commenting on what at best in unsubstantiated information - incident data or posts.
Irrespective of wether posters are from the industry, travelling public, or just spotters, … professionalism demands thoughtful responses.

"… information may want to be free, but it also wants to kill us."
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Old 21st Nov 2020, 09:40
  #27 (permalink)  
 
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Lots of conjecture here. I shall just wait for the Report, as no one really knows what happened, possibly not even the Pilots, sometimes happens, you deal with it and find out all the facts later during an investigation.

Lets be careful out there
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Old 21st Nov 2020, 10:18
  #28 (permalink)  
 
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"I shall just wait for the Report"

Will there be a report, publicly available?
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Old 21st Nov 2020, 10:58
  #29 (permalink)  
 
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Why reference the minimum speed to Vref rather than V2? Is it a Boeing thing that I have missed?
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Old 21st Nov 2020, 11:06
  #30 (permalink)  
 
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Of course if the aircraft is not behaving as it should, take control.

But this is a modern 777 right? Why would modern design allow this sort of thing to happen? (notwithstanding a possible ZFM error). Also the comments about Vref+80: it seems odd to me that a (heavy) aircraft can not keep to 250kts?

Last edited by Uplinker; 22nd Nov 2020 at 09:59.
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Old 21st Nov 2020, 11:07
  #31 (permalink)  
 
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Alex. The min manoeuvring speeds for various flap settings are based on Vref. So min clean in Vref+80, min speed Flap 1 is +60, F5 is +40. etc.
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Old 21st Nov 2020, 11:09
  #32 (permalink)  
 
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We could fly at 250, but not clean. If my MTOW 763 needed to fly at 250 Iíd need to keep F1 (min clean at this weight is 256).

ps. I have no idea what the equivalent speeds would be for a 777 but Iím guessing somewhat higher.
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Old 21st Nov 2020, 13:40
  #33 (permalink)  
 
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Why not klick klicken.....because coming out of automation usually results in a huge F'Up....especially in a busy traffic environment with a high rate of climb. The ALT hold VS method works well but it pays to brief it before hand, the trick is to wait for the nose to drop and the VS to come down, otherwise if you try to engage VS too early it will just recapture again. Freighters also have a higher flat rating compared to the pax aircraft so there can be huge amount of excess power even at max derate. Min clean can be above 250 at heavy weights, but they may have been empty.
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Old 21st Nov 2020, 14:13
  #34 (permalink)  
 
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"Absence of attitude protection in the autopilot's altitude capture mode"

A different type but same issue, aircraft flown by test pilots but still fatal......

https://en.wikipedia.org/wiki/Airbus...rie_Flight_129
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Old 21st Nov 2020, 14:34
  #35 (permalink)  
 
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allaru

I disagree. If automation has caused the tits up then the only way is to hand fly it. And I thought by now this is Industrie standard. Especially in the last few years were we have seen accidents through undesired aircraft states. This is basically were UPRT training comes in. Recover from the stall stabilise the flight path, then rebuild the autoflight system. Trying to fix a bad situation by fiddling with the FGS is not the way to go.
And I am not saying that this happend here. I was just replying to a nother comment.
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Old 21st Nov 2020, 17:11
  #36 (permalink)  
 
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allaru


I don’t fly a 777, but I disagree with this. If the automation is trying to kill me, the solution isn’t more automation. Especially in a potential stall.

(Bearing in mind that we really have no idea what caused the low energy situation. Everything here is speculation.)

Last edited by Check Airman; 21st Nov 2020 at 20:13.
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Old 21st Nov 2020, 17:16
  #37 (permalink)  
 
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A different type but same issue, aircraft flown by test pilots but still fatal......

Dropp: it didn't help that there was only one Airbus test pilot on board.
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Old 21st Nov 2020, 19:55
  #38 (permalink)  
 
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This doesn't seem so hard to imagine. I recall from personal experience that when doing an ICAO B Noise Abatement departure that any premature restraction of the flaps would almost immediately cause the stall warning to activate. The PM had to pay attention to the flap retraction schedule before moving the flap handle to the next retracted position, and if by chnce he went through the gate to the next flap setting you could expect that shaker to activate almost immediately. Moving the flap lever to the correct position would correct the problem along with lowering the nose at the same time. Attention getter for sure!
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Old 21st Nov 2020, 20:08
  #39 (permalink)  
 
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allaru

Sounds like you’re scared of hand flying.
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Old 21st Nov 2020, 20:19
  #40 (permalink)  
 
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Stall or stall warning? I would be 99% sure it was the latter.

Once you are in ALT, it follows a trajectory based on the rate-of-climb when it acquired. If youíve flown through a positive shear/gradient and maintained airspeed, the instantaneous climb rate at capture might be above what the aircraft can sustain without trading speed for height. If the A/P is in, you have to disconnect or accept a loss of airspeed during the capture.
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