Re: Way OT : Any maths bods around?

["Christopher Purves" <CHRIS_PURVES@xxxxxxx>]

But don't forget there are 4 of them. You need the joint (4-way)
distribution to calculate the likely hood. All 4 failing is a vanishing
small probability.

Chris


----- Original Message -----
From: Martin Howell<mailto:martin.howell@xxxxxxx>
To: ukha_d@xxxxxxx<mailto:ukha_d@xxxxxxx>
Sent: 28 February 2005 17:33
Subject: Re: [ukha_d] Way OT : Any maths bods around?



Its simpler than that, but worse if you worry a lot.  The MTBF is
calculated on the basis of the number of hours each test engine runs
before it fails, and then extrapolated as an average over all engines
built.  So one engine may last a million hours, but another only 100
hours with an average somewhere in between.

Martin

Hawes,Timothy Edward (GEG) wrote:

>1 in 10,000  ?  (100,000 MTBF / 10 hrs)
>
>It's probably more complicated than that, e.g. what happens if it's
>already flown for 99,989 hrs and you're flight is the last 10 before
>it's service ? I guess they're serviced at 50% of their quoted MTBF
>though and a 747 can still fly with one engine lost ?
>
>Not planning a trip are you ?
>;-)
>
>Cheers,
>
>Tim H.
>
>
>
>>-----Original Message-----
>>From: Ben McCormack
>>
>>OK this is way OT but I have got a query concerning maths and
stats.
>>
>>Right here goes
>>
>>An engine on a 747 has a Mean Time Between Failure of 100,000
Hours.
>>
>>So is there a simple calculation for the probability that an
>>engine will fail in a 10 Hour flight?
>>
>>
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>Yahoo! Groups Links
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