The PMU & PIU automatically control the propeller ________(pitch) & propeller ________ (Np)
blade angle; speed
True/False: The PMU controls the propeller RPM by varying the propeller blade angle with oil pressure through the PIU
True
With the PMU functioning, the mechanical overspeed governor modulates oil pressure to the propeller pitch change piston to limit Np below _____, while the electronic governor will maintain Np at ¬¬¬______.
106%; 100%
If PMU function is lost/deactivated, the mechanical flyweight overspeed governor modulates oil pressure to the propeller pitch change piston to maintain Np at or below___.
100±2%
Feathering the prop…when the engine is shutdown, the PMU sends a signal to the ________valve to drain propeller oil pressure.
prop servo valve
If the rate of change of propeller RPM occurs and exceeds the PMU sensor validity check limit, what will happen?
It will switch to manual mode
Does the PMU energize & de-energize the igniters when the ignition switch is positioned accordingly?
Yes
The PMU converts the 32 VAC from the PMA to ______.
DC
True/False: The PMU automatically switches to the 28 VDC battery bus when propeller RPM drops below 40-50% Np, or when the PMA fails.
True
PMU ground mode vs. flight mode
ground= 60-61%; Flight=67% (minimum)
Above ______, the PMU raises N1 to maintain Np above 80% to avoid stress on the propeller during spins.
10,000’ft PA
The PMU will auto abort an impending hot/hung start if ITT exceeds 940°C for _____, 870°C for _____, or 840°C for ______.
2 seconds, 4 seconds, 19 seconds
True/False: The PMU automatic shutdown feature is enabled for airstarts.
False, the auto feature is disabled
For engine starts, the PMU receives inputs from the ______ sensor located in the engine inlet plenum.
IOAT
If IOAT is greater than 96°C, but less than 121°C, the PMU will default to ______°C for all PMU functions
121°C
A dedicated ___________, mounted on the reduction gearbox, powers the PMU
Permanent magnet alternator (PMA)
If the IOAT exceeds 121°C, what happens to the PMU?
It goes offline & will not reset until below 121°C
If the ST READY light extinguishes during engine start, does the PMU auto abort function still work?
No, the start must be manually aborted
Illumination of both PMU ____ & PMU ______ annunciators indicates the system is in manual mode.
FAIL, STATUS
Why would the PMU STATUS light illuminate 1 minute after landing?
There were fault conditions not serious enough in-flight
Why would the PMU STATUS light illuminate during flight?
Mismatch between the weight on wheels switch & notifies pilot the PMU will not revert to ground mode upon landing
With the PMU off, the _______ will not automatically activate & must be selected manually for a PMU OFF AIRSTART.
Igniters
True/False: PMU FAILURE-before resetting PMU or switching to OFF, set power at lowest practical to minimize power shift.
True
Can you reset a PMU STATUS light in-flight?
No, the PMU detected a discrepancy w/the weight on wheels switch
