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by earthboundkid 1931 days ago
The machines are designed to tolerate fault, but the FAA is designed to not let you take off unless you do a checklist that proves all the engines are working, not just the one you need for a crippled landing. So the system as a whole requires that the FAA not give in to the pressure from industry to sign off on less fault tolerance. It's a difficult issue for systemantics.
1 comments
WalterBright 1931 days ago
Um, there isn't a backup if the backup isn't operable before you take off.
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AdamN 1931 days ago
That's their point. If the FAA didn't mandate it you can be sure budget airlines would be taking off and doing routes with one engine broken :-)
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sokoloff 1930 days ago
With wing mounted engines on two-engine airliners, there is physically no way to take off on one from other than a dry lake bed. The thrust from the operating engine will introduce more yaw on the airplane than the rudder, nosewheel steering, and wheel brakes can counteract.

Even tail mounted engines (with a shorter coupling arm to the centerline) will typically have a Vmcg (roughly, speed at which lateral control on the ground is lost with one engine inoperative) that will preclude takeoff on one (physically, not by regulations) from available runways.

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WalterBright 1931 days ago
That's not a fault of the airliner design.

> you can be sure

Not likely. Who you gonna get to fly it? Who you gonna get to pay to fly in it?

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andrekandre 1930 days ago
> Who you gonna get to fly it? Who you gonna get to pay to fly in it?

a. people in less developed countries

b. people in said countries with less money to spend than others

this has happened before (south america in the 70s, etc), which is why the aviation industry has the regulatory system it has today

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WalterBright 1929 days ago
Really? You know of examples of passenger planes taking off with only one engine turning? Or of any twin engine airplane doing this deliberately (other than a test flight or desperate emergency, like the volcano is gonna blow any moment).
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andrekandre 1929 days ago
i was lalking about the situation of planes taking off in barely flyable/safe situations that would not be allowed by modern faa regulations, which it think is larger point that was being argued, not debating about the single engine or propeller case

sorry if we ended up talking past eachother

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