APU
How long is a typical APU cool-down period?
3 minutes
What is the purpose of propellers?
The blades produce forces that create thrust to pull or push the airplane through the air.
What is used to control the amount of airflow through the cooling area of a reciprocating engine?
Cowl flaps.
What is the safety feature in an engine fuel system micron filter?
A bypass valve.
What is the size standard for electrical wire used in U.S. manufactured aircraft?
The American Wire Gage (AWG).
What type of operating practice could cause thermal shock and possible damage to an APU?
Abrupt shutdown of the APU when it is heavily loaded (not observing prescribed cool-down procedures).
What is a fixed pitch propeller?
A fixed pitch propeller is one that has a built-in blade angle that cannot be changed.
What happens to waste engine heat after it is transferred to cylinder cooling fins?
It is further transferred from the engine cylinders to the air.
What do the divided fuel flows of a turbine engine duplex fuel nozzle produce in the fuel?
Two spray patterns
What is the maximum slack allowed between the supports of a single wire or bundle installation?
Not over 1/2 inch.
How is the cool-down for many APUs accomplished prior to shutdown?
By running the APU for a specified minimum period of time after closing the bleed air valve (unloaded).
What is the purpose of metal tipping fastened to a wooden propeller leading edge and tip?
To protect the propeller from damage.
What should be done to a cylinder with excessive cooling fin area broken off?
Replace the cylinder.
What unit in a turbine engine fuel system is susceptible to the formation of ice?
The fuel filter.
What kind of wire is used for wires running close to exhaust stacks or heating ducts?
Wire with high temperature insulation material
At what speed does a gas turbine APU operate?
An APU operates at or near its rated speed regardless of the electrical or pneumatic loads imposed.
What types of systems are used for propeller ice control?
Fluid and electrical.
What type of power is used to operate cowl flaps?
Manual, electrical, or hydraulic.
What are the two categories of turbine engine fuel pumps?
Constant and Nonconstant (variable) displacement.
What is an indication of a dirty, worn, starter commutator?
The starter is excessively noisy.
Whats used to typically start an APU ?
Its own electric starter and battery power.
When engine vibration is reported, what should be checked to determine if it is caused by the engine or propeller?
Blade tracking and blade angle setting.
Where should cowl flaps be positioned during ground operations?
Fully open.
What are the purposes of main fuel strainers?
To collect water and sediment, and keep foreign matter out of the carburetor.
Where are generator rating and performance data located?
They are stamped on a name plate attached to the generator.