Starting Systems Flashcards
On large engines, where are the starters found?
Mounted to external gearbox
How does the turbine help with the starting sequence?
Turbine helps starter till engine gets to idle
What percent RPM can the turbine support the engine?
35%
What is happening in the engine during a hot start?
Too much fuel, not enough air (EGT Rise)
What happens during a hung start?
Engine fails to accelerate
What should you do during a hung start?
Abort start
Which types of starters are no longer in use because of their weight?
Single purpose starters
What is the typical TBO of a starter-generator?
1000 hrs
Where should you inspect a starter-generator?
Drive splines for wear
Brushes for length
Which airplane uses an electric starter?
787
What are the parameters of a Low Pressure Axial Flow air starter?
After Passing through a start valve, air passes through a set of Convergent Ducts (Turbine Nozzle Vanes)
Air speeds up turbine in starter to around 60-80K Rpm
Need separate oil supply, shear shaft, and ability to choke nozzle vanes
Sprag clutch disengages starter
How long does the starter usually stay engaged?
Up to 40-45%
How does a hot start happen?
Starter is disengaged following a “Light off”
ATA chapter for starting
ATA80
ATA chapter for electrical power
ATA24
How do high-low pressure pneumatic starting systems get their power?
May be operated using conventional low pressure air from APU, Ground cart, or running engine. Or in special circumstances, an onboard bottle.
Starters that use gas produced by the rapid burning of an explosive charge are called
Cartridge pneumatic starters
Instead of having a starter mounted to the external gearbox, this starting system supplies high volume/low pressure air directly to the turbine wheel of the HP compressor
Air Impingement starting
This system uses another turbine engine to start the larger engines
Gas turbine starter
