FlyerTalk Forums - View Single Post - Irrational: I avoid 2-engine 777 transpacific

Nov 2, 2006 | 9:22 pm

#58

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Quote:

Originally Posted by rar indeed

I'm not sure why there should be such a difference... are 4 engine planes better-maintained and are the engines in 4 engine planes more reliable? I bet the answer is no. I view each event as having a set probability of failure given the maintenance, age, etc etc of the engine, not the configuration in which it is used.

Suppose an engine fails 10% of the time. In 100 flights, a twin-engine would have 20 engine failures. A 4-engine plane would have 40 failures. If a single failure took each plane down, the 4 engine would fail twice as often.

(yeah, yeah wise guy, I know - independent trials, 1% probability of dual independent failures, actual probabilities are slightly lower.... it's late and I don't feel like doing the math. EDIT - OK I did the math, 81% vs. 66% probability of success)

Back to my original question. A twin-engine can obviously operate on one engine. Does a four engine plane require three, or can it operate on two? Three engine plane?

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