Re: ETOPS

From:         kls@ohare.Chicago.COM (Karl Swartz)
Organization: Chicago Software Works, Menlo Park, California
Date:         12 Oct 96 21:34:29 
References:   1 2 3 4
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>Question: Have there been historical grounds for fearing twin engined
>planes over the ocean ? (eg: was there a time when JET engines often
>failed during flight ?)

Prior to the development of ETOPS in the late 1970s and 1980s (while
ETOPS appeared for the North Atlantic in the 19080s, the US pioneered
the idea in the 1970s with a 75 minute rule time for the Caribbean),
ICAO rules required an aircraft to be able to limp home with *two*
failed engines.  This even precluded trijets operating at high weights,
never mind twins.

Much of this conservatism was based on piston engines, which were much
less reliable than any sort of turbine.  The reliability of jets has
increased greatly over the years, but I suspect they're more likely
to fail at startup or on takeoff rather than during cruise, so ETOPS
might have been feasible even in the 1960s.

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Karl Swartz	|Home	kls@chicago.com
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