reply to post by Verd_Vhett
...also somthing people often overlook, avgas is heavier then water per gallon, In emergency landings or ditches they dump the full if possible
the terrorist did not ...
Sorry,
Verd, that needs to be corrected.
Avgas is NOT heavier than water. BTW, 'Avgas' refers to 'Aviation Gasoline', which is a lot like automotive gasoline, except in higher Octane
ratings and stricter refining standards, plus has dyes added to denote the Octane levels.
Anyway, Avgas weighs approximately 6 pounds/US Gallon, compared to water which is 7.5 lbs/Gal.
And, Avgas is used in piston airplanes, reciprocating engines. NOT turbine engines.
Jet-A is a form of diesel, designed for turbine engines. It is heavier than Avgas, average of 6.7 lbs/Gal. Still, lighter than water.
In emergency landings or ditches they dump the full if possible...
Key words there are "if possible". NOT all jets have the capability to dump. The B757 does NOT -- the B767 does.
Reason for less fuel onboard in the event of a ditching is merely to provide greater buoyancy, shuld the ditiching be successful and result in minimal
structural damage. The wings, less fuel, and undamaged will be quite buoyant. USAir 1549 is an example of A) Good technique, yet still there was
damage in the very rear of the fuselage, and water came in and B) Passenger panic, and one rear door was opened slightly, a no-no since they usually
are below the waterline, as the airplnae floats tail-low usually.
Otherwise, for an emergency on land where a normal landing is anticipated, the dumping would only be for weight reduction, but depends on emergency.
Landing gear malfunctions? Time is not critical, so fuel burn-off or dump is logical. Engine failure/fire?? Immediate landing regardless of weight.
Not all emergencies are the same.