> >  OK, I stand corrected. :-)  The point was a triple engine failure due to
 > > the same maintenance error repeated three times.  This is the key flaw
 > > in the triple redundancy approach if you don't stagger your maintenance
 > > on the three units.
 > >
 > > Bill Freeman


 > Mark wrote>
 > The introduction of ETOPS (Extended Twin Ops - Allowing twins to fly up to
 > 207mins from an Alternate) has had a huge effect on airline safety. Due to
 > the concerns Bill mentioned, ETOPS certification requires that an Airline
 > prove that their maintenance program is set up to avoid dual maintenance on
 > critical systems during a single ground time. If it can't be avoided, the
 > work must be performed by independant crews, it this can't be done, the
 > aircraft will be downgraded to Non-ETOPS for the next flight.
 >
 > The effect of this has been so positive on safety that most 3+ engine long
 > haul operators adopted this principle for their aircraft,
although it is not
 > strictly required. The next version of the 777 (LR - Long Range up to 18
 > hour commercial flights) will mark the move beyond ETOPs to
LROPs. This will
 > remove the artificial limits (like 180 mins from an airfield) to
be replaced
 > by aircraft limits. eg an A/C may have a 5:20 limit on oil quanitiy under
 > MAXCON thrust. They are looking at the next improvements to maintenance
 > safety.
 >
 > Then again, who wants to fly for 18 hours? Imagine Sydney-Rio via the south
 > pole. About 7 hours with no alternate after you pass Christchurch.
 > Wrathall Mark

ETOPS - Engines Turning Or Passengers Swimming     : )

James Russell

 
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