Classic British Flight Sim

Chris Trott wrote:

forthbridge wrote:

3a: On fuel contamination, what is the primary worry? Water in the fuel or some other contaminant?

Motormouse wrote:
2) Big aeroplanes usually have more than one pump in each tank, colloquially known as 'booster pumps' each one is capable of supplying all the necessary fuel to the engine driven high pressure pump, and below @ 10,000 ft, the 'suction' pressure alone from the engine pumps will keep engines running

On RR engines, there is an LP fuel pump, followed by a LP filter and finally the HP fuel pump.


On a more personal note the a/c would have come in over the building I worked in up to a couple of years ago, so if the the incident had happened 20 secs earlier at that time............

Makes you think though, if the Stanstead Korean accident had occured at LHR, or the Concorde accident had happened there, there would now be a few areas of open ground amonst all that housing in the Feltham area

Paul

Motormouse wrote:1) Most of the time fuel for an individual engine will be drawn only from its' respective tank ie
left tank feeds left engine, right tank feeds right engine (in the case of the 'gimli glider' the source of the problem, a broken fuel pipe at the engine,was exacerbated by crew using 'cross-feed' to feed fuel from opposite tank to affected side)

Pete

Refuelling

At the time of the incident, Canada was converting to the metric system. As part of this process, the new 767s being acquired by Air Canada were the first to be calibrated for the new system, using litres and kilograms instead of gallons and pounds. All other aircraft were still operating with English measurements. For the trip to Edmonton, the pilot calculated a fuel requirement of 22,300 kg. A dripstick check indicated that there were 7,682 litres already in the tanks. In order to calculate how much more fuel had to be uplifted the crew needed to convert the quantity in the tanks to a weight, subtract that figure from 22,300 and convert the result back into a quantity. (This task had previously been completed by the Flight Engineer, but the 767 was the first of a new generation of airliners operated by two flight crew and the Flight Engineer position had been made redundant.)

A litre of jet fuel weighs 0.803 kg, so the correct calculation was:

7682 litres x 0.803 = 6169 kg
22300 kg – 6169 kg = 16131 kg
16131 kg ÷ 0.803 = 20163 litres

Between the ground crew and flight crew, however, they arrived at an incorrect conversion factor of 1.77, the weight of a litre of fuel in pounds. This was the conversion factor provided on the refueller’s paperwork and which had always been used for the rest of the airline’s imperial calibrated fleet. Their calculation produced:

7682 litres x 1.77 = 13597 ‘kg’
22300 kg – 13597 ‘kg’ = 8703 kg
8703 kg ÷ 1.77 = 4916 litres

Instead of 22,300 kg of fuel, they had 22,300 pounds on board — only a little over 10,000 kg, or less than half the amount required to reach their destination. Knowing the problems with the FQIS, the Captain double-checked their calculations but was given the same incorrect conversion factor. All he did was check their arithmetic, inevitably coming up with the same figures.

The Flight Management Computer (FMC) measures fuel consumption, allowing the crew to keep track of fuel burned as the flight progresses. It is normally updated automatically by the FQIS, but in the absence of this facility it can be updated manually. Believing he had 22,300 kg of fuel on board, this is the figure the Captain entered.

Because the FMC would reset during the stopover in Ottawa the Captain had the fuel tanks measured again with the dripstick whilst there. In converting the quantity to kilograms, the same incorrect conversion factor was used. Believing they now had 20,400 kg of fuel, they still only had less than half the amount they actually needed.

petermcleland wrote:If it ain't broke why fix it?...Pity they didn't just leave their aircraft in gallons and pounds :brick: