fuel system Flashcards
describe the fuel system
crashworthy suction type with self sealing tank
function of the prime/boost pump
can prime all lines and also acts as a boost pump for APU ops
2 reasons we may get a fuel pressure warning
malfunction of eng driven fuel boost pump or air leak in system
will we get a fuel press or bypass indication if there is water in the fuel
may not
what does putting the fuel pump switch in apu boost do
opens apu fuel shutoff valve and activates prime boost pump
what does putting the fuel pump in fuel prime do
opens both eng prime shut off valves
main fuel tank capacity
590 usable gallons (4012 lb JP-5)
what does the left fuel cell have provisions for
single point refuel/defuel, gravity defuel, HIFR
it also has 2 high level shutoff valves, a check valve, sump drain and vent
what does the right fuel cell have
2 check valves, a sump drain, vent, apu fuel line, fuel dump system
how much of the tank is self sealing
lower 1/3
what is the interconnect level of the two sides of the fuel tank
270-600 lb per side
size of the aux tanks
113 or 120 gal
purpose of the 2 thermistors in the aux tank
one is an overflow sensor one is a low level (empty) sensor
aux tank pump/valve fail vs auto fuel xfer fault
when a single pump/valve fails we get the fail
when both fail we get the fault
does auto fuel xfer fault guarantee we can’t use the fuel
no manual mode might work
purpose of the 2 transfer dump pumps
either shifts fuel from the aux tanks to the main tank or dumps fuel
what fuel do you have to get to in the main tank to do an unmonitored manual fuel xfer
less than 3200 lb
after we have burned ___ lb we can do a manual fuel xfer check
300 lb
when can we not all stores jett the aux
less than 40 gal or approx 272 lb of fuel but since it reads in 50 lb increments assume anything 300 lb or less will need to sel jett
fill sequence with both aux
main, right, left
when will auto xfer occur
around 2640 lb
auto fuel xfer sequence
left then right
if the FMCP is messed up how do you bypass the precheck valves
pull its CB
what kind of sensor is used to measure fuel level
capacitance type probe that uses fuel as a dielectric
