The Crash of Turkish Airlines flight 1951

medium.com

40 points·darkhorn··7 comments

The autothrottle automatically pulling the throttle back sounds so much like MCAS preventing nose being pulled up and in both cases, it seems the pilots did not know previously these kind of activations could happen.

Aviation herald article of the crash http://avherald.com/h?article=41595ec3/0070&opt=0

100 crash analyses by the same author:

https://www.reddit.com/r/AdmiralCloudberg/comments/by4s2x/pl...

"A radio altimeter measures a plane’s height above terrain by bouncing a radio signal off of the ground and recording the response time."

If that's the case, how come a negative reading was not assumed as a malfunction? Am I missing something, or can a plane ever be in negative altitude with respect to whatever this radio signal is bouncing off from?

edit: s/never/ever/

Radio altimeters always have some margin of error, so a slightly negative altitude reading doesn't necessarily mean it's malfunctioning. A better approach would probably be to cross check the radio altimeter with the GNSS receiver and navigation system, then alert the pilots in case of a sustained large discrepancy. Of course that would further complicate the avionics and risk introducing additional failure modes.

Thanks!

Medium links should be banned as long as they have that popup.

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