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Comment by pc86 | Hacker News Reader

Saying it's "probably" anything based off of two lines of text (even with a correlating video) is ridiculous irresponsible, and will almost always be wrong. Not to mention the fact there are a whole host of things that can cause a 6kfpm descent, both controlled and uncontrolled, that are neither terrorism nor the horizontal stabilizer.

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I already acknowledged this was a speculative line of thought. Don't think any air crash investigators are looking into a nobody on the internet for accident clues, so it's a kind of very limited irresponsibility.

However there are actually not that many causes, that could explain the vertical drop either than, and in order of decreasing probability:

- Suicide/Terrorism

- A Jackscrew Mechanism Failure: https://www.wikiwand.com/en/Jackscrew

- Accidental Deployment of the Reverse Thrusters.

The accidental deployment of the reverse thrusters, is something that requires multiple mechanical failures, is not supposed to happen but Boeing already has a past history with it, although on a different model. The Niki Lauda/Boeing controversy.

"What if the reversers OPEN in flight?!"

Video at correct time: https://youtu.be/OguKthkuaT4?t=1026

If the reversers open, wouldn't just shutting down the engines lead to a better scenario than this? I recall a 737 gliding too a nearby airport in Canada when it ran out of fuel.

I suppose it depends on whether the crew would have been aware of it.

It all happened in less than 2 minutes. The airplane could be in a unrecoverable nose dive faster then could even realize what is happening.

Can the reversers be opened independently on left and right side? From some of the 3D plots on various threads it looks like the plane took a sharp left before diving. Could it be the left reverser malfunctioned or be accidently opened mid flight causing the plane to swirl left and lose the aerodynamic?

They can. Although incredibly rare. There are a few military airplanes that use reversers in flight to quickly drop altitude, but not used in any commercial passenger airplane that way. That scenario of only one opening, is also addressed in the video from Mentour Pilot that I linked. A few minutes earlier in the video. They have a checklist for it.

Do you work in the aerospace industry?

>Saying it's "probably" anything based off of two lines of text (even with a correlating video) is ridiculous irresponsible

And as long as the number in the corner keeps getting bigger people will keep doing it.

You get what you incentivize. The purpose of a system is what it does.

I think it was more than 6kfpm. The plane dropped from 22000 in 2 minutes. Especially the end was fast. The dash cam footage looks almost vertical.

Maybe the VSI was reporting incorrect data due to the crazy fast descent. Or it was a report from the beginning of the dive?

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