Originally Posted by
jayteeto
No it didn’t
i wonder why?
it would be nice to find out
i know, let’s have an inquest to examine ALL the issues
genius
Personally, I don't need any special hidden story to picture what possibly had happened:
- your job is to fly a type notorious for various fuel level indicator flaws (stories from the fire fighter brigarde about pressure washing engines hot or cold, tiny but effective water droplets in the tank, etc)
- your boss tries to stretch a sortie as far as possible, almost bordering on having you cut into your fuel reserve
- its pitch dark outside
- you constantly have to toggle them dry-run sensitive fuel pumps, due to an inferiour fuel pump type (at least compared to EC135s ancestor BO105, which has a similar tank setup but dry-run capable pumps)
- these very important switches are overhead, hence out of sight
- you keep acknowledging the "faulty" low fuel warnings, while the main tank gauge indicates "~80kg remaining" (hence you are convinced they are as faulty as you've heard. Nobody told you about the sensor types and their extremely different sensitivity to ingressed water)
- while the display still indicates ~80kg of fuel the first engine dies on you
- with the home base lighting in sight, you frantically try to prepare for OEO flight, assured that you've got another 1,5 mins till silence, hence can fly home
- trying to get home on one engine with still "80 kgs remaining" indicated, the second engine goes silent "prematurely", some 30secs after the first
- now the cockpit goes truly black, rad-alt and landing-light gone, thanks to stupid electrical setup
- real panic sets in because nobody ever let you practize/demonstrate a "both engines at idle" autorotation, let alone a true EOL (not even in a sim?)
- the acoustic environment is waaay different than usual, RRPM indicator is as black as the rest of the cockpit, RRPM hard to tell by ear (wearing a helmet)
- between overrevving the MR and trying to arrest a "normal" RRPM, (hard to tell w/o instrument or visible blades) you are trying to pick a landing spot
- you end up below the min. end of the "RRPM power off" arc
- end of story
I don't see how this is survivable for anyone.
Who would have taken the time to mentally backtrack all previous actions to find the wrong pumps to be on?
So many systems were preceived by the pilot to have failed:
- recurring low fuel warnings while 80kg indicated in main tank, although one recalls humbly acting on the illuminating pump dry run indicator lights mutiple times in this very sortie, hence reasoning "it can't be the pumps"
- engine starving while 80kg indicated
- second engine starving way earlier than stated in the POH
There is only one on single contribution of the pilot to this accident:
having switched off both transfer pumps and switching on both prime pumps.
Anything else is airbus' fault:
bad choice of fuel pump type, necessitating unnecessary, error prone pilot work
bad choice of fuel sensor type, water-droplet sensitive fuel level sensors are a stupid choice
bad choice of emergency electrical power (it costs one(!) diode to fully automatically route battery power to the bus, thereby taking over supply when both generators fail)
That accident would never have happened in a BO105:
when both engines are running you make sure both transfers pumps are on, switch off the prime pumps and forget about pumps until you land and shutdown.