JF Mezei wrote:
> On 13-07-30 08:04, Uwe Klein wrote:
>
>
>>The 787 probably is the only use case where ELT batteries had to be
>>replaced early in the lifecycle ( customers requiring the full battery
>>lifetime on their new planes. ) on a regular basis.
>>
>>Thus probably a combination of less than optimal design ( the design allows
>>pinching ) and
>>"make haste" workmanship at Boeing ( or whoever changed the batteries there )
>
>
> If the ELT used on the 787 is used exclusively on the 787, why did
> Boeing include a whole bunch of other aircraft in the AD ?
>
> From a PR point of view, I could see Boeing including the other aircraft
> in order to not focus on 787 problems.
I wouldn't put it beyond them to go that way.
_And_ you can probably pinch the battery wires on all these ELTs.
But for now only ELTs installed on 787 aircraft have had issues afaik.
> But that would cost airline
> operators a lot of money to disconnect all those ELTs until more study
> is done all this to save the 787's image ? Don't think so.
Not Boeings money ;-)
I wonder what fringe benefits Boeing has handed out for 787 customers
be rather mum about issues with the type.
Think about what A380 post EIS banalities have been trudged out by the press
and compare to the long time of silence until that battery nonfire in Boston
and the resultant exposure of a long string of previous definitely not banal
problems encountered after EIS. ( And apparently without much improvements
over time. Next month the 787 completes 2 years in airline use!
At that time the A380 was doing 12..14 hours per day in Airline service
and without hours of preventive care applied pre every flight.
afaics the 787s doesn't get beyond 4 hours per day that they were available for
flying )
>
> The ELT is made by Honeywell and would generally be independant of
> aircraft systems. (But I assume that it does get power from aircraft to
> keep its batteries charged ?).
ELT batteries are primary type batteries. ( i.e. not recharable and single use )
They have limited shelflife/servicelife ( 2 .. 7 years dependent on type )
My assumption is that they are field replacable.
Then Boeing must have a bunch of them fitted to various languishing frames
and customers when they finaly get their frame will demand fresh batteries.
>
> One possible difference would be the environment in which the ELT is
> positioned. Could it include extreme heat and cold because it is so
> close to the skin ? Would other ELTs be placed close to roof of aircraft
> ? (On a sunny day, I suspect the skin on roof could get might hot on
> tarmac, especially with dark livery).
No dark livery for Ethopian ;-)
>
> But Shirley Boeing would have considered this when designing the 787 ?
> Where are ELTs located in older aircraft ?
Obviously Boeing is the brightest candle around and
never will misdesign, overlook or even run into unknown unknown trouble.
Then Boeing has for a long time been a PR department with an
airframer arm and select employees that have a hand for utilising gifted
research work. ( i.e. all that aerodynamics research information
found at the DLR in Göttingen in 1945 )
uwe