Lack of redundancies on Boeing 737 MAX baffles some involved in developing it

Re:Lack of redundancies on Boeing 737 MAX baffles some invol... by dragonsky67 on Tuesday April 02, 2019 @11:32PM (#19560523)

If there are three of the same type (make/model?) of sensor teaming to vote on the status being measured I'm not suprised that they can suffer the same failure (iceing) at the same time causing an incorrect state to be upvoted.

I would have thought that for any condition there would be more than one mechanism available to sense it. You could get different devices to vote on what is the real condition.

This has been done for years in visual cockpits with regards to an artifical horizon. The pilot only has to look out the window (assuming visibliity) to confirm what the instrument is reporting. Of course when the pilot loses visibility and starts to rely on their inner ear for "level" bad things can happen.

Many more simple planes, especially things like gliders, have a simple ball bearing in a curved tube to indicate "down" as well as the more convential artifical horizon.

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Re:Lack of redundancies on Boeing 737 MAX baffles some invol... by danaliv on Tuesday April 02, 2019 @11:48PM (#19560562)

Are you talking about a turn coordinator? That doesn't show "down." The sum of forces acting in a coordinated turn will keep the ball centered even though the airplane is banked.

Also I'm not sure what you're talking about with using the real horizon as a backup to the artificial horizon. It's not meant to be a redundant setup. Artificial horizons aren't required for visual (looking outside) flight, and relying primarily on the instruments in visual flight is an error.

In clouds/poor visibility, the cross-check for the artificial horizon is provided by the other flight instruments: airspeed, altimeter, turn coordinator, vertical speed indicator, and directional gyro (or their equivalents on an electronic display).

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Re:Lack of redundancies on Boeing 737 MAX baffles some invol... by dragonsky67 on Wednesday April 03, 2019 @01:17AM (#19560954)

The point is that you are using a different type of device to cross check the reading from the first. In the case of the faulty sensor, it sounds like they are using the same type of device therefore conditions that impact the effectiveness of that device will likely impact more than one of them.

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