SY103/104 Propulsion Flashcards
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What are the three elements necessary for engine operation?
Air
Fuel
Heat
The purpose of the inertial separator is to ____.
keep debris away from the engine
What type of engine is the T-6 equipped with?
Pratt & Whitney PT6A-68 free turbine, reverse flow design, turboprop engine
The major sections of the engine are (3):
Accessory compartment
Gas generation section
Power turbine section
What are the components of the gas generation section? (4)
Compressor Inlet
Compressor
Combustion Chamber
Compressor Turbine
The power turbine section contains the following components (4):
Power Turbines
Exhaust Case
Reduction Gearbox
Propeller Shaft
What are the two components of the engine exhaust system?
Exhaust Ports
Exhaust Stack
What are the 3 components of the ignition system?
Ignition Exciter
Two High Voltage Igniter Cables
Two Spark Igniters
During engine start, move the PCL between “OFF” and “IDLE” until the _______ annunciator illuminates.
ST READY
What is ITT? Where is it measured?
Interstage Turbine Temperature
ITT is the temperature inside the engine. ITT is taken by sensors located between the power and compressor turbines.
The PCL is connected via a flexible cable to the ____ and via electronic signal to the ____
FMU
PMU
A PMU Status Annunciator is indicative of either:
PMU has accommodated a fault, or
A mismatch between the weight-on-wheels switches
alerting the pilot that the PMU will not revert to the ground mode upon landing
In addition, the yellow MASTER CAUTION light will illuminate
A nonfunctional PMU will illuminate which annunciator lights?
PMU FAIL (red) PMU STATUS (yellow)
as well as the MASTER WARN and MASTER CAUTION lights
The primary power source for the PMU comes from the _____.
Permanent Magnet Alternator (PMA) which is mounted on the reduction gearbox.
The generator provides ____ VDC Power
28 VDC
What are the 3 components of the oil system?
Pressure System
Scavenge System
Cooling System
What does a CHIP annunciator light (red) indicate?
Metal particles are detected in the oil
Oil level must be serviced within ___ minutes of engine shutdown
30 minutes. 15 to 20 minutes is the most accurate
An amber OIL PX annunciator will illuminate when oil pressure is between ___ and ___ psi at IDLE power or between ___ and ___ psi for ___ seconds above IDLE power.
15 and 40 psi at IDLE
40 and 90 psi for 10 seconds above IDLE
If oil pressure is ___ psi or below at IDLE power, the amber OIL PX annunciator will extinguish and the red annunciator will remain illuminated.
15 psi
If oil pressure remains between ___ and ___ psi at IDLE power for 5 seconds or more, both annunciators will be illuminated.
15 and 40 psi
100% torque is available from SL to approximately _____ to _____ feet MSL on a standard day.
12,000 to 16,000 MSL
A backup mechanical overspeed governor will not allow prop RPM to exceed ____% (____ RPM)
106% 2120 RPM
If the PMU or PIU fails, it will regulate to 100% +/-2%
In the feathered condition, the blade angle is approximately ___ degrees
86 degrees
Propeller speed is monitored by the ____ ____ ____ ____.
phase shift torque probe
During a start sequence, ITT operating limits are from ____ C to ____ C
After startup, limits are from ____ to ____ C
400 to 1,000 C
400 to 820 C
What does N1 represent?
What are the normal operating limits? (%)
Gas Generator Speed
60-104%
Data for the _____ is NOT processed by the PMU.
AEDD (Alternate Engine Data Display)
What causes the amber CKPT ALT annunciator to illuminate?
Cockpit Altitude exceeding 19,000 ft on the AEDD
What causes the red CKPT PX annunciator to illuminate?
Cockpit pressure differential exceeding 3.9 to 4.0 psi
The firewall shutoff handle shuts off (3):
Hydraulic Fluid
Fuel Flow to the engine
Bleed air flow from the engine
What pushes the propeller to feathered position?
Fixed cylinder Sliding piston Feathering spring Fork assembly Cam follower
What are 3 types of abnormal starts?
Hot
Hung
No Start
Indications of a Hot Start
High/rapidly rising ITT
Lower N1
Lower Np
Hung Start Indications
Slow Rising ITT
Lower N1
Lower Np
(Hung start is where the gauges rise but seem to stop in place)
No Start Indications and Possible Causes
Indications: No ITT indication Lower N1 No Np Indication No torque indication
Possible Causes: PMU Failure FMU Failure Starter Failure Ignition System Failure Incorrect air/fuel Mixture
Indications of Engine Failure
Initial Indications: Loss of power and airspeed Rapid decay of N1, torque, and ITT MASTER WARN lights and tone Propeller moves toward feather
Accompanying Indications:
Rapidly decreasing ITT, Np
Lower-than-normal oil pressure
Engine noise
GEN, FUEL PX, OIL PX, OBOGS FAIL annunciators
Possibly PMU FAIL and CKPT ALT annunciators
Indications/Possible Causes of a PMU Failure
Indications:
Power Step Change
PMU FAIL and PMU STATUS annunciators
MASTER WARN light with tone
Possible Causes:
System Failure/Malfunction
Indications of Uncommanded Power Changes/Loss of Power
Indications: Reduction in power/thrust Lower than expected fuel flow Uncommanded decrease in N1 High raw ITT (RITT) on AEDD
Possible Causes:
Engine rollback due to PMU scheduling
Oil/engine/fuel system contamination
Uncommanded Feather Indications and Possible Causes
Indications: Rapid loss of power High torque* Lower Np* Possible PMU FAIL/PMU STATUS annunciators Engine vibration Engine noise
Possible Causes:
Feather dump solenoid malfunction
Loss of oil pressure to propeller pitch control mechanism
Prop Sleeve Touchdown Indications and Possible Causes
Possible Indications: Np fluctuations Increasing torque Decreasing thrust Engine vibrations Possible CHIP detector warning light
Possible Causes:
Loss of oil pressure to prop pitch control mechanism from momentary contact between oil transfer sleeve and propeller shaft
Engine Fire in Flight Indications
Fluctuating (fluids) oil press, oil temp, or hydraulic press Excessive turbine temp Visual indications Erratic engine operation Roughness or vibration
Possible Causes:
Fuel or oil leaks
Fire getting outside the engine
Possible Causes of Engine Failure In-Flight (3)*
Fuel Starvation
Mechanical Failure
Compressor Stall
The PMA provides _____ VAC which the PMU converts to DC.
If the PMA fails will the PMU fail?
32 VAC
No, the power will be provided through the 28 VDC battery bus.
Where is the CHIP detector sensor located?
In the reduction gearbox
What does the PROP SYS circuit breaker provide power to?
Feather Dump Solenoid Valve
What monitors and processes engine operation data?
Engine Data Manager (EDM)
What are some tasks performed by the EDM?
Drives the primary, alternate and engine/system displays
Illuminates advisory, caution and warning annunciators when appropriate
Non-engine related tasks:
fuel balancing, fuel quantity indications, activation of the nose wheel steering annunciator, a display of DC volts, DC amps, hydraulic pressure, NACWS, cockpit pressure altitude, and cockpit pressure differential
What is the ranges for the DC voltage on the ESND? (amber/white/amber/red)
amber up to 21.9V
white from 22.0 to 29.5V
amber from 29.6 to 32.2V
red at 32.3V and above
