RSS Feedswing fuel tank booster pumps?
hi,
my questions are;
1- from where the wing booster pumps take their energy (not APU booster pumps, because the APU booster pumps get the energy from battery power)
2- why we need booster pumps, why dont the low pressure fuel pump be used instead of booster pump ?
3- if the APU not available, aircraft starts with the external power. does this power include electricity besides the pnomatic air ? and such a condition, can booster pumps take their energy from the external power ?
have a nice day world and aviators …
Most Larger modern jet aircraft use a three phase AC operated DC controlled electrical fuel pump located in the fuel tanks to pump the fuel from the tanks to the engine even though there is an engine driven fuel pump mounted on the engines as well. The reason for this is to keep a positive fuel flow from the tanks to the engines during rapid throttle movement or at higher altitudes where vapor lock is more likely top occur. The AC power is supplied from the engine driven generators in-flight or either an external AC power source or an APU while the aircraft is on the ground.
If a modern commercial aircraft has an inoperable APU, the aircraft can still be started using external power sources. This includes both Electrical and pneumatic power supplies. The pneumatic power is used to rotate the starter motor. Electricity is supplied to operate pumps, valves switches and gages used in the engine start sequences
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January 12th, 2009
1)Older aircraft have Mechinacal pumps.The way these work is a Diaphragm is moved via a lever connected to the crankshaft. On the newer aircraft they are usually eletrically powered.
2) Many reasons. Gravity feed alone wont get enough fuel to a jet engine and if it does, you need a means of controling fuel flow into the engine. Also on some aircraft this allows for extra redundancy in case the engine driven pump fails. Some boost pumps also act as scavengers. When fuel levels get low, you may not have as much fuel flowing effectivley. Also, higher pressure means less chance of vapor lock as well as it raises the boiling and flash point tempratures.
3) External units can supply both Eletrical energy and Phneumatic pressure.
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January 12th, 2009
Battery power is available to more than just the APU, but once the APU is started, it drives a generator that also provides electrical power to the rest of the aircraft.
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January 12th, 2009
Most Larger modern jet aircraft use a three phase AC operated DC controlled electrical fuel pump located in the fuel tanks to pump the fuel from the tanks to the engine even though there is an engine driven fuel pump mounted on the engines as well. The reason for this is to keep a positive fuel flow from the tanks to the engines during rapid throttle movement or at higher altitudes where vapor lock is more likely top occur. The AC power is supplied from the engine driven generators in-flight or either an external AC power source or an APU while the aircraft is on the ground.
If a modern commercial aircraft has an inoperable APU, the aircraft can still be started using external power sources. This includes both Electrical and pneumatic power supplies. The pneumatic power is used to rotate the starter motor. Electricity is supplied to operate pumps, valves switches and gages used in the engine start sequences
References :
Flight Engineers Know This Stuff
January 12th, 2009
1. wing boost pumps are a/c . They get there power from apu generator, external ,or engine generator 2. boost pumps are a means of a secondary fuel pump and to create a positive flow to engine and there 2 installed in each wing. 3. all larger commercial aircraft start the first engine from pneumatics from the apu or a ground source called a huffer. Yes ,you can run a boost pump from external power. We do it all the time ,to transfer fuel, start a engine when apu is inop,start apu at the gate.
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