APU Limits Flashcards
Normal APU RPM range when providing bleed air?
100 +/- 3% RPM
Continuous APU EGT operating range?
200°-715°C
APU RPM red line (over speed)?
110%
APU automatic shutdown protection for over speed?
110 (+/-1) %
When is APU Auto Shutdown Protection disabled?
During Start Cycle
APU Starting Limit: below _____ RPM, APU EGT can peak as high as _____ for up to _____.
Below 60% RPM, APU EGT can peak as high as 980°C for up to 2 seconds.
During APU-Assisted engine starts, APU EGT can peak as high as?
760°C for 2 seconds.
APU start is unsuccessful if APU RPM does not exceed ___ within ___?
60% within 30 seconds.
APU start is unsuccessful if APU EGT does not decrease towards continuous operating range as RPM increases above?
60%
After an unsuccessful APU start, wait _____ between each attempt with up to _____ attempts, then wait _____ for APU to cool down.
1 minute between attempts, with up to 3 attempts, then wait 20 minutes for APU to cool down.
Do not operate APU longer than ____ with the APU generator off?
5 minutes with the APU generator off.
After the APU is used for starting or motoring an aircraft engine, the APU must run unloaded for?
2 minutes prior to shut down.
On the ground with engines at IDLE, leave APU running if aircraft is modified with?
OBOGS or for cockpit cooling if temp is above 85°F.
After a successful ground APU start and shutdown, wait?
10 minutes after APU shutdown before attempting another APU start.
After a successful inflight APU start and shutdown, wait?
2 minutes from initiating the previous start before attempting another APU start.
