Originally Posted by
evil7
There are hundreds of 135īs flying around and only this one fell out the sky because the feeder tanks ran dry. The fuel system can‘t be that complicated I think.
Consider this: there are (were) many BO105s flying around, where so I'm told, you switch on both transfers pumps and
leave them that way till end of trip.
No toggling them depending on whether one does a prolonged hover or goes 120kts. Apparently the BO105 pumps have no issues running dry.
Hence I for one would never have approved certification of an a/c whose fuel system mangement is more hassel the its predecessor's.
But then again I, too, would have dismissed a fuel level sensing system that is
the opposite of fail save:
e.g. one that indicates way more fuel in the tank than there actually is as soon as a droplet(!) of water gets in between the two concentric fuel sensor tubes.
Mind you it's ok if it
is affected by water ingress but it is paramount that it were fail SAFE, meaning in that case it may only indicate LESS fuel that there actually is.
So with 1) a decent fuel supply system and 2) a fail safe fuel sensor system that accident simply wouldn't have happened.
Capable pumps simply stay on till engine shutdown at home.
Fail safe fuel indicators wouldn't have created a laid back attitude toward various fuel warning lights illuminating, where recurrent acknowledgement of them might become standard behavior.
It might be hard to memorize which fuel warning light really means business when lit and which might just indicate a recently hot pressure washed turbine.
Then again I guess I might be way to critical (and/or uninformed) to work in an certification environment.
Here a quote from some BO105 FM Pg. 3 - 14
WARNING LIGHT INDICATIONS
LOW FUEL
Conditions/Indications Failure of both main tank pumps, or Main tank empty
– Supply tank fuel quantity below 60 kg (75 l)
Procedure
1. Supply tank fuel level – Check
2. Main tank fuel level – Check
3. Both fuel main pump circuit breakers – Check in
4. Both fuel main pump switches – Check on
If LOW FUEL warning light remains on:
5. LAND WITHIN 10 MINUTES