Fuel Systems Flashcards
What are the 2 types of fuel systems?
Gravity & Pump
What are the 8 basic fuel system components?
Tanks
Lines
Valves
Filters
Gauges
Pumps
Warning Signals
Primer
What FAR is for airworthy fuel systems on aircraft certificated prior to Aug 29 2017? What does it state?
FAR 23.955
Gravity fuel systems 150% take off
Pump fuel systems 125% take off
No sharp bends in lines
Separate from electrical wires
What FAR is for airworthy fuel systems on aircraft certificated after Aug 30 2017? What does it state?
FAR 23.2430 (a) (3)
Provide the fuel necessary to ensure
each powerplant and APU functions
properly
What is the FAR for fuel systems on transport aircraft?
FAR 25.955
What is the FAR for fuel systems on Rotorcraft?
FAR 27.955
The fuel storage system must
provide fuel for at least _________
of operation at maximum continuous
power or thrust and be capable of
jettisoning fuel safely if required for
landing.
one-half hour
What 2 identifiers are required to be on the filler port placard?
Fuel type & Fuel grade
What are the 3 types of fuel tanks?
Rigid removable
Bladder
Integral
Integral fuel tanks must have _____ _____ for inspection and repairs of the
tanks and other fuel system
components.
access panels
What are the 4 most common types of fuel quantity indicators:
• Sight Glass
• Mechanical
• Electrical
• Electronic Capacitance
What is Vapor Lock?
Vapor lock is pockets formed by this
premature vaporization restrict the
fuel flow through units which are
designed to handle liquids rather
than gases
What are the 3 general causes of vapor lock?
The lowering of the pressure
on the fuel
High fuel temperatures
Excessive fuel turbulence.
What are 3 ways to reduce the possibility of vapor lock?
Keep fuel lines away from sources of heat
Sharp bends
&
Steep rises
What is the major improvement in reducing vapor lock?
The incorporation of booster pumps in the fuel system
What is the name for the main strainer?
Gascolator
What is the purpose of the gascolator?
Prevent foreign matter from entering
the fuel metering unit
Where is the gascolator located?
At the lowest point in the system
Where are the other strainers/filters located?
In the tank outlet and inlet to fuel metering unit
What is the fuel pressure for a float carburetor?
0.5 - 8 psi
What is the fuel pressure for a pressure carburetor?
12 - 17 psi
What is the fuel pressure for fuel injection?
5 - 30 psi
Where is the shutoff valve located?
Aft of firewall (outside of the engine compartment)
What does the main pump do?
Feeds fuel to engine during normal
flight
What does the auxiliary (boost pump) do?
Provide fuel for priming and
starting the engine
Also provides adequate inlet
pressure to engine pump to prevent
vapor lock
When is the auxiliary (boost pump) used?
Operated during :
High Altitude
Take off and landing
High Temperature
What are the 3 types of pumps?
Wobble
Diaphragm
Vane
What is the most common pump on smaller aircraft?
Diaphragm
(Engine driven)
What is the most common pump on large reciprocating engines?
Vane
(Engine driven)
What is positive displacement?
All fuel that enters pump will pass through
(Must have a pressure relief valve)
What is a compensated type mixture control?
Uses a diaphragm to compensate
fuel pressures as altitude changes
Vane pumps must also have a ______ valve
Bypass
What is a bypass valve?
Lets fuel bypass main section of
pump for engine start and in case of
an inoperative pump
What is a plunger pump?
An electrically operated auxiliary pump
