aircraft system Flashcards
are designed to provide an uninterrupted flow of clean fuel to the engine
aircraft fuel system components
utilizes the force of gravity to transfer the fuel from the tanks to the engine
gravity-feed system
this places thee fuel tanks above the carburetor, and the fuel is gravity fed through the system and into the carburetor
gravity-feed system
if the design of the aircraft is such that gravity cannot be used to transfer, this is installed
fuel-pump system
aircraft with fuel-pump system have two fuel pumps
main pump system or engine driven pump and electrically driven auxiliary pump
pumps the fuel from the tank to the engine
main pump system or engine driven pump
provided for use in engine starting and in the event the engine pump fails
electrically driven auxiliary pump
other term for auxiliary pump
boost pump
provides reliability to the fuel system and is electrically driven by a switch in the cockpit
auxiliary pump
allows air into the tank as fuel is consumed
fuel vent
used to draw fuel from the tanks to vaporize fuel directly into the cylinders prior to starting the engine
fuel primer
during cold weather, when engines are difficult to start, this helps because there is not enough heat available to vaporize the fuel in the carburetor
fuel primer
allow air into the tank as fuel is consumed
fuel vents
normally located inside the wings of an airplane, have a filler on top of the wing through which they can be filled
fuel tanks
covers the opening of fuel tanks
filler cap
stores the fuel and protects from contaminants
fuel tanks
all fuel tanks are required to have what
sump and drain installed at their lowest point
provides a convenient location for water and sediment to settle, allowing it to be drained from the system
sump
indicate the amount of fuel measured by a sensing unit in each fuel tank and is displayed in gallons or pounds
fuel gauges / fuel quantity gauges
when do aircraft certification rules require accuracy in fuel gauges
when they read “empty”(but other reading than “empty” should be verified
allows selection of fuel from various tanks
fuel selectors / selector valve
four positions of a common type of selector
left, right, both, and off
fuel flows through a small metal what from the tank to the engine
fuel line
fuel lines routed in an engine compartment present what
special maintenance consideration
often constructed from synthetic materials with the line’s diameter being dependent upon the engine’s fuel flow requirements
flexi fuel lines
also a kind of coarse filter used for separating solid particles of a different size.
strainer
usually used to remove large solid contaminant particles
strainer
used for fine filtration
filter
requires a main strainer or fuel filter to be installed in the fuel system to remove contaminants and to provide a method for draining the contaminants from the system
FAR Part 23
represents the lowest point in an aircraft’s fuel system and should be checked periodically for contaminants that could restrict fuel flow to the engine
fuel strainer
explain the process that happens in the fuel strainers, sumps, and drains
after leaving the fuel tank and before the carburetor, fuel passes through a strainer that removes moisture and sediments that settle in a sump at the bottom of the strainer assembly
low point in a fuel system and/or fuel tank
sump
may contain a sump, fuel strainer, and fuel tank drains, which may be collocated
fuel system
why is water in the sump hazardous
in cold weather, the water can freeze and block fuel lines. in warm weather, it can flow into the carburetor and stop the engine
serves to remove water from the tank or to drain the fuel
drain valve
important of an aircraft drain valve
high quality seal
primary fuel pressure pumps in a pressure-feed fuel system
engine-driven fuel pumps
deliver a continuous supply of fuel at the proper pressure during engine operation
engine-driven fuel pumps
maintain a positive fuel pressure on the inlet side of the engine-driven fuel pump. this helps prevent pump cavitation and vapor lock by pressurizing the fuel in the lines
auxiliary fuel pumps / boost pump
may serve as a backup source for fuel pressure to the engine-driven fuel pump becomes clogged or fails
auxiliary fuel pumps / boost pump
if an engine has both engine-driven fuel pump and a boost pump, this must be incorporated into the fuel system
bypass valves or check valves
when pumps are in series this is used
bypass valves
when pumps are in par-all
check valves
purpose of of bypass and check valves
let fuel bypass the engine-driven pump during engine starting or in case the pump fails
purpose of this is the same as a reciprocating engine fuel system
turbine fuel system
must store, transfer, and meter fuel to a turbine engine in the proper amount and at the right pressure
turbine fuel system
what does a fuel system contain
tanks, lines, valves, pumps, filter devices, gauges, a fuel control unit, and fuel nozzles ++ fuel heater
required to eliminate fuel metering problems caused by ice crystals in the fuel
