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This came to my mind when I learned 737 MAX crash was caused by the AOA indicators giving faulty info to the AI which crashed the plane.

So how do you completely disable the flight computer when it starts to control the plane but putting pressure on yoke or forcing the trim wheels dont solve anything? How do you remove the circuit breakers on a Boeing or a Airbus?

Altough this question seems like just another override the AI question. What I really want to know is how do I COMPLETELY disable the flight AI. It caused accidents when it happened in test flights but Id like to take a risk.

Delta Oscar Uniform
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    If it is not MCAS specific, then it is too broad (each type will have different procedures). Note: the system is not classified as AI. –  Mar 30 '19 at 09:25
  • @ymb1 then I'd like to see an answer telling how to disable all of them – Delta Oscar Uniform Mar 30 '19 at 09:28
  • As I understand it, the flight control computers (which are not AI) on an Airbus are an integral part of the control system. If you completely disabled them you'd have no control at all. In that instance your question makes no sense. I think the same is true for some Boeing models, but I'm not sure. – CatchAsCatchCan Mar 30 '19 at 09:50
  • Who said anything about AI? – 60levelchange Mar 30 '19 at 11:20
  • @J.Hougaard: OP mentions AI three times, once in title and twice in last paragraph. No idea where they got that from, maybe the OP just means "software" in general? – RedGrittyBrick Mar 30 '19 at 11:26
  • @RedGrittyBrick Yeah my comment was directed toward OP, I can see now why that might not have been obvious – 60levelchange Mar 30 '19 at 13:32
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    @ymb1 the definition of AI is (at least for me) "A computer software that does actions (Pitching the nose down or changing lanes) according to the inputs (Either AOA sensors or radars designed to see cars with the camera system to see lanes) without human interference" so yeah I think it can be counted as AI. – Delta Oscar Uniform Mar 30 '19 at 14:47
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    @Jonathan Irons - isn't that a definition of any data processing software that doesn't require human input? – Dave Gremlin Mar 30 '19 at 17:52
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    Your definition (if we ignored the unnecessary requirement it be software) would call a mechanical thermostat (turns the heat on/off according to the temperature input without human interference), which dates back hundreds of years, AI. – Zach Lipton Mar 31 '19 at 00:51

1 Answers1

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TLDR: you follow the appropriate checklist for your aircraft.

For example:

737 Runaway Stabilizer checklist

How do you disable plane AI

There is no Artifical Intelligence (AI) in passenger transport aircraft.

Colloquially, the term "artificial intelligence" is used to describe machines that mimic "cognitive" functions that humans associate with other human minds, such as "learning" and "problem solving"

So far as I know, avionics systems pretty much have to follow a rigorously tested and designed but fairly traditional style of imperative and deterministic programming that does not involve the kinds of techniques that computer scientists might associate with AI, such as knowledge-based-systems, rule-based systems, fuzzy-logic, inference engines, etc.

737 MAX crash was caused by the AOA indicators giving faulty info to the AI which crashed the plane

There have been two crashes in which MCAS (not AI) is thought to have played a part. After the first crash, but before the second, the FAA issued an Airworthiness Directive (AD) that specified what action to take in the case of "uncommanded nose-down inputs".

Required by AD 2018-23-51

Runaway Stabilizer
In the event of an uncommanded horizontal stabilizer trim movement, combined with any of the following potential effects or indications resulting from an erroneous Angle of Attack (AOA) input, the flight crew must comply with the Runaway Stabilizer procedure in the Operating Procedures chapter of this manual:

  • Continuous or intermittent stick shaker on the affected side only.
  • Minimum speed bar (red and black) on the affected side only.
  • Increasing nose down control forces.
  • IAS DISAGREE alert.
  • ALT DISAGREE alert.
  • AOA DISAGREE alert (if the option is installed).
  • FEEL DIFF PRESS light.
  • Autopilot may disengage.
  • Inability to engage autopilot.

...

Required by AD 2018-23-51

Runaway Stabilizer
Disengage autopilot and control airplane pitch attitude with control column and main electric trim as required. If relaxing the column causes the trim to move, set stabilizer trim switches to CUTOUT. If runaway continues, hold the stabilizer trim wheel against rotation and trim the airplane manually.

...

It may be that the pilots in the second incident did not follow the revised checklist for this situation, or were not able to for some reason. More recent information suggests that following the runaway stabilizer checklist can disable MCAS but also disables the ability to adjust trim "manually" using the thumbswitches on the control column. At some point there was a change in the wiring/operation of the two STAB TRIM CUTOUT switches so that both have the same effect rather than being able to selectively disable automatic trim while retaining the operation of the thumbswitches. This only leaves manual operation of the trim wheels - which can require a lot of strength in some circumstances.

The faulty AoA sensor and the actions of MCAS may have contributed to the accidents but there are other causative factors that need to be understood by anyone dealing with this situation. Battle over blame, BBC

Note that Boeing will now fit AoA disagreement indicators to 737s. I believe they also have issued MCAS revisions.

how do you completely disable the flight computer

There isn't one computer.

There are many computers. Usually there are different computers for each function and there are multiple redundant computers for the same function. If you want to disable a computer, you need to know what function you want to disable and know what effect that will have on everything else you are relying on. This is why there are checklists for pilots to follow for non-routine and for emergency situations.

I'd like to see an answer telling how to disable all of them

Modern passenger transport aircraft are very complex, there are many breakers, in multiple locations. Some of those locations are sometimes not in the cockpit.

It isn't possible to give, in this Q&A website, a complete list of all breaker locations for all passenger transport aircraft currently in service.

It caused accidents when it happened in test flights but Id like to take a risk.

People who like to take risks do not (or should not) pilot passenger transport aircraft like the 737.

RedGrittyBrick
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