Re: Problems in a commercial flight

Mxsmanic wrote:
Sometimes it is simulated just because pilots expect it.

So you admit that in expecting it, the pilots must necessarily feel it (or rather, expect to feel it; want to feel it; know that they should feel it; know that it should exist).

I don't know why it's true.

Then how can you say that it is not false?

But at the same time, they
are extremely rare in large commercial airliners, so practicing them in excess
(to the detriment of practice in other, more likely emergency scnearios) is
probably not a good idea.

In small aircraft, the engines are so unreliable that engine failures must be
practiced.

Surface analysis of the NTSB database would seem to mete this out; last year there were just 2 incidents in jets, while general aviation racked up 25. However, without a more detailed report of accidents per flight or per mile (or per capita), I would be hesitant to make such claims with authority.

Ironically, more of the GA accidents with fatalities occurred in large turbine/heavy twin aircraft, while small "tin-cans" were generally non-fatal if not merely incidental.


(setting an engine to idle
doesn't count).

Why not, if the purpose of the practice is to experience a loss of meaningful power and to execute the proper diagnostics to the engine as well as the correct emergency procedures? Idling the engine would seem to be a perfect solution.

Some Airbus aircraft are designed to be unstable, under the assumption that
computers will keep them flying straight and level.

Which?

... why design systems that fail catastrophically?

Systems fail catastrophically when they are _not_ designed. Catastrophic
failure modes are characteristic of unanticipated exceptions in digital
systems.

Surely an engineer would anticipate the failure of a computer system. Heck, that's why we have triple-redundancy hydraulic systems (with backup electrics, no less).

That same engineer would also surely see that using an active control system (with a failure potential) is inferior to using plain old physics (which has already been demonstrated on many other designs; why try to fix what isn't broken)?

That cannot be done with digital systems. They only fail safe in modes that
are anticipated in the design; in other modes, catastrophic failure is more
likely.

But the system in question here is not digital, nor is it controlled as such by the fly-by-wire systems. Dihedral in a wing uses physics (and a helping hand from Mr. Daniel Bernoulli) to roll an aircraft level (or more towards level), sans control inputs. Why would an engineer ignore this time-tested approach to wing design in favor of an active (and potentially failure-prone) system?

That would not be verification.

But it would start the process.

Yes, and it is vastly overrated in consequence. Many incorrectly assume that
the mere presence of references somehow validates whatever uses them.

I think many assume that the presence of references provides a trail of fact-checking and verification which is important when trying to assert the validity of analysis and claims made in such academia.

Your use of the term puzzled me,

I'm not sure why; I used it to indicate two separate concepts, which you promptly corrected me by saying that they were.... independent.

It would have seemed to the outside viewer that perhaps you had not understood the usage.

They need to do their own research.

Hard to do without a platform to stand on from which to begin, eh? It would hardly be fair if you wanted to verify my claims of why the sky was blue, but you had to discover the atom first (and then molecules, dipole bonding forces, light refraction, fusion, astronomy, and various other sundry basal sciences), right?

Public services usually aim to provide helpful and useful information, as well as a stepping stone for learning more about the topic, not commands from on-high from an individual who holds himself in higher standing than his peers.

TheSmokingGnu
.

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