NATOPS CH2.5 Auxiliary Power Unit Flashcards
Whats the purpose of the APU?
The APU provides pnematic power for starting engines and for operating the Environmental Control System
What is the APU and what does it consist of?
Its a gas turbine engine consisting of a power section, a reduction gearbox, controls and accessories.
How is the APU lubricated?
It has a self contained lubricating system
How much fuel does the APU consume?
150lbs per hour
When is the APU used during flight?
It is not intended for routine in-flight use. Operation of the APU SHALL be limited to essentially operations only.
Including Emergency Procedures, Single Engine Traning, Practice Autorotations, and powering the ECS during extreme temp ops
What does it mean when NATOPS says the APU doesn’t have a Turbine wheel containment device?
An uncontained APU figure may result in injury to ground personnel and/or damage to critical components including the tail rotor drive shaft
How much pressure is needed in the accumulator to start the APU?
What are the ways to charge it?
2,650psi is required to start the APU.
It can be charged by the backup hyd pump, or by the accumulator hand pump
Describe what the APU DESU does
Whats required to maintain the BIT codes?
The APU is controlled and monitored by the Digital Electronic Sequence Unit (DESU)
if the start sequence fails or a monitored parameter is exceeded the DESU will shut down the APU, it wil then display the BIT codes
To maintain the codes DC power is required and the APU CNTL switch must remain in on position
How long does it take the backup pump to charge the Accumulator?
Placing the backup pump switch in ON then back to OFF/AUTO will turn the pump on for 90sec (180sec if the winterization kit is installed)
