Re: interesting ETOPS stats from UAL

Date:         29 May 98 02:43:32 
From:         kls@ohare.Chicago.COM (Karl Swartz)
Organization: Chicago Software Works, Menlo Park, California
References:   1 2
Followups:    1 2
Next article
View raw article
  or MIME structure

>	These _are_ interesting stats. Does UA say anywhere how many ETOPS
>flights suffered engine problems that required a diversion within the
>180-minute (is that right?) distance?

Nobody ever puts anything negative in a press release unless they're
forced to do so.  Especially not an airline.  They wouldn't even admit
that engines *could* have problems, never mind how often that had
happened!

I have seen stats from engine manufacturers on in-flight shutdowns per
thousand hours of operation, though.  According to an article in Flight
International from June 4, 1988, the GE CF6-80C2 had "an engine-caused
in-flight shutdown rate of 0.009 per 1,000 flying hours."  A subsequent
article in the April 1, 1989 issue of the same publication claimed the
CAA requirement for 120-minute ETOPS was that "the engine type must have
a shutdown rate of fewer than 0.05 per 1,000 flights," with plans to
tighten that to 0.03 in the future.  Odd that the regulation supposedly
was written in terms of rate per 1,000 *flights*, versus per 1,000 hours
as in the GE statistics.  I don't know if that's really the way the
regulations are (were) written of if it's just an error in the article,
Rate per 1,000 hours makes more sense to me.

BTW, it wasn't easy to confirm, but all of UA's ETOPS aircraft are
certified for 180-minute ETOPS, even though none other than the 757s
are currently used on routes where they need more than 138-minute
ratings.

--
Karl Swartz	|Home	kls@chicago.com
		|Work	kls@netapp.com
		|WWW	http://www.chicago.com/~kls/
"The average dog is a nicer person than the average person." - Andrew A. Rooney