A321 loses AP controls in flight & automatic speeding violation x2 below 10,000 ft

Hello,

I’m writing to report an issue with my A321. @chris_s sent me to the #support board. I’ll admit that I turned around to grab a soda while this happened, but essentially I was flying fine in clear weather and enabled the autopilot features (airspeed, altitude, heading) without issue. But, when I came back to my iPad Pro moments later, my airplane was in a free fall with all autopilot features disabled and apparently speeding >150 KIAS (while under 10,000 ft). This caused me to get -2- separate speeding violations.

Can you please advise what may have caused this? The weather was clear, so I cannot attribute that. It was also flying just fine when I turned on the autopilot parameters. The airplane doesn’t usually have this issue. I’m baffled as to what happened. I’d appreciate any advice in case it was my own handling that caused the autopilot to go awry…I’d also appreciate if you can remove the -2- speeding violations as these were obviously not intentional. I couldn’t regain control of the aircraft once it was in this free fall.

Thanks!!

Here’s the replay video…

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Not sure if violations can be removed. Do you know exactly on the replay, when did the Autopilot turn off? This might be a known issue right now with A321 having Autopilot issues.

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Hi @airfrance005 — I’m not sure exactly but can re-watch to get the timing. I’d hope at least -1- of the -2- can be removed because it’s really all the same event…and none of it intentional!

Violation will be removed if you have evidence. Please ensure, that you reviewed the replay file. A moderator should see this.

Hey.

I’m not sure exactly what the issue is here? :)

Looking at the replay, the autopilot disengages as you’re basically stalling the aircraft? Or am i missing something? :)

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Hi, @schyllberg …yes, I lost control immediately despite everything else being normal. I’m not sure why it went into a stall. I had just flown under the same parameters minutes before. I engaged AP after positive climb rate as normal but still experienced an unexpected stall.

Thank you!

Side note: I did just finally try cursing at FL310 and noticed that the bobbing issue is apparently resolved! Thanks!

Unrelated. Don’t land on other aircraft… go around.

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Thanks, AirFrance005! I’m not sure what caused the stall since I was flying under the same conditions and location within 5 minutes prior.

There are many other things, I’ll PM you with all of them to help you improve. :)

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@trio Thanks …I didn’t see the aircraft until it was too late to safely execute a missed approach. I had been cleared though, so I think that aircraft shouldn’t have been there. I otherwise had (in other situations) and would have gone around.

Am I watching a different replay here or something? Not sarcasm, but it seems like people are talking about totally different things than what I’m seeing. This is from the takeoff… I don’t see anything normal :/

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The climb after you set the AP must have been too steep, this likely caused it to disengage, don’t set the AP until you or aircraft is stable and monitor it. I think you just need more practice flying, that’s all

@schyllberg It’s okay. Hmm…I only remember having had taken off normally and gotten positive climb to engage AP before my attention was drawn away for a moment and thence the stall. It wasn’t unlike how I regularly engage AP otherwise after take off…though obviously I’m otherwise watching and/or engaging With the iPad/app to make sure these things don’t happen!

Indeed, you can only operate the autopilot after reaching an altitude of 3000 fts. no matter what you do nothing bad will happen and you will be able to sip a soda without fearing a sudden fall.

good luck.

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@Chatta290 Hi thanks. That could certainly be true. It’s just unusual to have happened here but not in the many iterations prior.

@Jean-Marc_Koumaya Hmmm, I genuinely did not know that to be the case. Is that true for all aircraft (<3k ft)?? I usually Turn on the heading right after takeoff, followed shortly thereafter by the vertical speed and/or altitude and lastly the speed. I manually control the speed until it’s safe to switch to autopilot. But I feel like i’ve Otherwise gotten AP to work fine below 3k ft.

What I’m seeing here, is that you’re trying to take off way too soon.

For example:

  • There was no flaps deployed when rotating, you put those down mid-climb.
  • You rotated around 120-125kts and could barely get off of the runway, with the tail scraping quite a lot.

You didn’t see this? I’m asking because based on what i see in the replay, the AP was engaged several times and then disengaged automatically as the aircraft couldn’t maintain lift due to the high VS and low speed. I also hear the flaps going up & down.

There’s no error with the aircraft here I’m afraid to say :/

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Try to take an A321 off at 140 knots (medium weight). It really helps.

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Wow I didn’t even remember this. If that’s true, I’m sorry And those errors would make sense. I must have been unusually distracted but remember things being fine until I turned back to a stalling airplane.

Side note: That said, I also usually fly with my iPad Pro in its case, typically with the keyboard down. I think this affects the calibration because generally I can fly just fine, but from time to time, the calibration really doesn’t seem to do anything. Of course on my end, I can just try to keep the keyboard closed…but I just mean to say that I’ve wondered how/if it affects calibration—particularly during takeoffs.

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Watch your own replay and you’ll see :) You’re almost vertical during takeoff and you can barely see the flight path vector sometimes as your angel of attack differs so much due to the stalling :)

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