Fuel dump/jettison in stormy area
 

Hi everybody,

I'm looking about restrictions for fuel jettisson (in flight) in stormy weather conditions. Can't see anything in 777 FCOM, I don't remember on A330. Do your compagny or your aircraft's manuel mention any kind of restriction or recommandation about this particulary situation?

This is a cut and paste from the OMA of a now defunct airline:

"The jettison operation should not be conducted below 6 000 ft above ground.
Fuel jettison in a holding pattern and descent within the area previously used for jettison should be avoided in order to remain outside the kerosene cloud.
Fuel jettison should not be performed in the vicinity of thunderstorm activity."

From a Bombardier QRH:
Jettisoning of fuel in known lightning conditions is prohibited.

Boeing information, as I recall it, is that at normal speeds for fuel jettison the flame front burns slower than the aircraft is moving so it will always drift backwards and never catch up with the aircraft.

BizJetJock

Wait a minute, I had no idea that a Bombardier could jettison fuel.

Depends on the type. The 600 series models with tail tanks are able to dump the tail if the transfer system fails or is inhibited folloewing a rotor burst to prevent the c of g going too far aft as you burn off the rest of the fuel.

Are there any documented cases of dumped fuel being ignited by anthing other than an afternurner?

There was a flying boat back before WWII that exploded and crashed while dumping fuel.
Granted, that was gasoline, not jet fuel, and the investigation was cursory, but food for thought...

Thanks for all gentlemen ...

Further informations, it's written in:

- OACI doc
- EASA doc
- A340 abnormal proc
- A 380 abnormal proc
- A350 abnormal proc
- B 744 abnormal proc etc....

It seems to be everywhere but in 777/787 doc. Are those aircrafts lightning-proof?

I read about a c46 that exploded over the hump that was attributed to fuel entering the janitrol

Boeing 720 or 707?
 

Iirc at a military demonstration during the 60s one flew through it’s fuel dump and exploded. There was a film clip of it.

Could one apply common sense?