Posts about: "Engine Shutdown" [Posts: 142 Page: 8 of 8]ΒΆ

Musician
February 04, 2026, 11:16:00 GMT
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Post: 12032148
Originally Posted by Chernobyl
The problem with your stated concern is how do you prevent it? Simple, you say: interlock it with the thrust levers and/or radio alt and/or baro alt in some combination to ensure you can ONLY switch to cutoff if not below 400' ft or at takeoff thrust. But what happens if this new logic fails in a novel way in the future preventing an engine shutdown when it really IS needed? Any new complexity adds potential unintended consequences and hence risks. Is the cure worse than the disease? Right now, the switch design is entirely consistent with Boeing standard practice: flight crew actions are the final say.
AFAIK Embraer has the switches interlocked with the thrust levers so they won't cut off unless at idle, and Citations require moving the thrust lever past idle?
Obviously Boeing can't easily change "standard practice", especially if they want to keep training costs for pilots switching types low, but that doesn't mean it's not a good idea in general.
If this logic fails "when it is really needed", the pilot can still pull the fire handle. Or the engine won't start, but then they'd still be sitting at the airport. But I don't think the aircraft that already have this have had issues?


Subjects Engine Failure (All)  Engine Shutdown  Fuel (All)  Fuel Cutoff Switches

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Abbas Ibn Firnas
February 05, 2026, 00:36:00 GMT
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Post: 12032516
Originally Posted by Chernobyl
The problem with your stated concern is how do you prevent it? Simple, you say: interlock it with the thrust levers and/or radio alt and/or baro alt in some combination to ensure you can ONLY switch to cutoff if not below 400' ft or at takeoff thrust. But what happens if this new logic fails in a novel way in the future preventing an engine shutdown when it really IS needed? Any new complexity adds potential unintended consequences and hence risks. Is the cure worse than the disease? Right now, the switch design is entirely consistent with Boeing standard practice: flight crew actions are the final say.
Yes, the more complex a system becomes, the greater number of failure modes could be envisioned.

This reasoning doesn't correspond with how modern aircraft are designed and constructed though. They have been made ever more complex, precisely in the name of safety.

If you take this "any new complexity adds potential unintended consequences" philosophy to the extreme, why not stay with cable operated flight controls, remove flap extension protection or WOW sensors, or any one of the systems that are designed into modern aircraft?
It usually takes something bad to happen in the exact same way a few times before a change is made. I hope this is not one of those situations.


Subjects Engine Failure (All)  Engine Shutdown  Fuel (All)  Fuel Cutoff Switches

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