Strange Autopilot Issue with Violation

Hello, recently while flying a ULH I was cruising straight with a 787-8 at .95 as directed by my VA’s operations manual. All of a sudden, my AP just decides to blast through Mach 1.00 for no apparent reason which gave me a violation, I was wondering if this violation could be removed as I believe it was a system error that caused this, feel free to look at my replay below.

The violation I was given was for going over 0.90, but I was flying 0.95 the entire time and didn’t get one, so I could use some help figuring this out.

Was it the wind/weather refreshing?

I recommend you just slow down a little bit. You may seem to fly a
little too fast.

Ehrm, your VA needs to look over their operations manual…

Sorry but this just keeps looping for me when i read your topic…

Regarding the issue, the replay does unfortunately not show AP controls. But in 100% of the similar reported cases we’ve seen with this up to now, it’s been caused by a 3rd party app used for speed and altitude control, where as the speed were incorrectly inputted into the 3rd party app.


That .1 mach too high. Suitable cruise speeds should be around .85.


Hmm okay, but I was not using a 3rd party application during this flight though, is there something else that could have happened? @schyllberg

Oh yea, just read it again and realised it was infact .85, whoops. But that still doesnt make sense as to why the aircraft blew past mach 1.0 for no reason as it was flying straight without any fluctuations in angle or alt.

@Aceorbit… MaxSez: What where wind aloft at your pos when the M increase was noted, Plus; Don’t push the envelope, the data noted in any pub is for ideal flight tested situational. Wx, load factors/Balance, Trim all must be considered. Ya gotta fly the Dam# plane, , don’t let it fly you, Scan continually avoid speed creep.

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Follow this for 787-8

I think the majority of you guys commenting are missing the point, this support thread is not questioning speed, but is instead trying to figure out the issue of why Autopilot decided to accelerate past the speed it was set at, when it was already at the speed it was set at, and it was flying in a straight path without any fluctuations in altitude or angle…

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