Engines, APU Flashcards
Explain what is indicated by a REV indication above the N1 indicator
REV amber - thrust reverser moved from stowed position
REV green - thrust reverser is deployed
Describe the engine abnormal start protection (ground starts only)
During ground starts, the EEC monitors engine parameters to detect impending:
- hot starts
- engine stalls
- EGT start limit exceedances
- wet starts
These protection features do not function during inflight starts.
If an impending hot start is detected by a rapid rise in EGT or EGT approaching the start limit, or a compressor stall occurs, the white box surrounding the EGT digital readout flashes white. The EEC software automatically turns off the ignition and shuts off the fuel to the engine for an impending hot start or stall
If the EGT exceeds the starting limit, the EGT display, both box and dial, turn red. The EEC automatically turns off the ignition and shuts off fuel to the engine
A wet start occurs if the EGT doesn’t rise after the start lever is moved to IDLE. If a wet start is detected, the EEC turns off the ignition and shuts off fuel to the engine 15 seconds after the start lever is moved to IDLE.
Explain what is indicated by an amber REVERSER light on the aft overhead panel
The REVERSER light, located on the aft overhead panel, illuminates when the thrust reverser is commanded to stow and extinguishes 10 seconds later when the isolation valve closes. Any time the REVERSER light illuminates for more than approximately 12 seconds, a malfunction has occurred, and the MASTER CAUTION and ENG system annunciation lights illuminate.
Explain the meaning of the amber APU LOW OIL PRESSURE light
Oil pressure is low causing an automatic shutdown (after start cycle is complete)
Explain the meaning of the blue APU MAINT light
APU maintenance problem exists
Note: call maintenance
Explain the meaning of the amber APU FAULT light
A malfunction exists causing the APU to initiate an automatic shutdown
Explain the meaning of the amber APU OVERSPEED light
- APU RPM limit has been exceeded resulting in an automatic shutdown
- Overspeed shutdown protection feature has failed a self-test during a normal APU shutdown
Recall the function of the Electronic Engine Control (EEC) switches
- ON (white): indicates normal control mode is selected
- ALTN (amber): EEC has automatically switched to alternate control mode, or it has been selected manually
Note: both ON and ALTN may be in view if EEC has automatically switched to soft alternate mode. EGT limits must be observed in all control modes
Explain the meaning and location of an amber ENG FAIL alert
- Displayed on the EGT indicator
- Engine operating below sustainable idle (less than 50% N2), and engine start lever in IDLE position
Explain the meaning of a framed red box around the N1, N2 or EGT indicators
On ground, after both engines shutdown, red box indicates an exceedance has occurred
Describe when the engine start lever should be placed to IDLE during a normal engine start
Position engine start lever to IDLE detent when N2 RPM reaches maximum motoring and N1 rotation is observed
Note: maximum motoring occurs when N2 acceleration is less than 1% in approx. 5 seconds
Recall when the ENGINE START switch automatically moves from GRD to OFF during an engine start
At 56% N2 RPM; if not position start switch to OFF
Recall the conditions that will cause the APU auto shutdown
- FIRE (red)
Amber: - LOW OIL PRESSURE
- OVER SPEED
- FAULT
Recall when the APU is ready to accept a bleed air or electrical load
The blue APU GEN OFF BUS light illuminates when the APU is ready to accept a bleed air or electrical load.
Electrical power may be used immediately.
A two-minute stabilization is recommended to extend the service life of the APU before using bleed air. Operate the APU for 2 full minutes after illumination of the APU GEN OFF BUS light before using it as a bleed air source
Describe the function of the N1 SET knobs
N1 SET outer knob:
AUTO:
- both reference N1 bugs set by FMC, based on N1 limit page and takeoff reference page
- displays reference N1 bugs at active N1 limit for A/T
BOTH:
- both reference N1 bugs and readouts manually set by turning the SET inner knob
- has not effect on A/T operation
1 or 2:
- respective N1 reference bug and readout manually set by turning N1 SET inner knob
- has no effect on A/T operation
N1 SET inner knob (spring loaded to center), rotate:
- positions reference N1 bug(s) and readouts when N1 SET outer knob is set to BOTH, 1, or 2
