MUHAMMAD NURRIDZMAN BIN ZAHRIN
53106118224
5AEM6
Practical Assignment:
1. One of the methods used to mount the propeller assembly to the engine is by the spline shaft.
a) Briefly describe the spline shaft.
Shaft that has ridges or teeth that mesh with grooves in a mating piece and transfer
torque so that a hub will fit on the shaft in only one position.
b) Discuss how you ensure the proper installation of the propeller assembly by using the spline
shaft.
Position of the propeller on the hub in relation to the master spline is critical. Some
installations require that one blade aligns with the master spline while other installations
require that the blades be perpendicular to the master spline position. Always refer to the
engine maintenance manual for the requirements of a particular installation.
c) What are the problem encounter and
Problems that are encountered are rear cone and front cone bottoming. Rear cone
bottoming occur when the apex or point of the rear cone contact the land of the rear seat
of the hub before the hub becomes seated on the rear cone. Front cone bottoming occur
when the apex of the front cone bottoms on the shaft splines before it seats on the hub,
indicated by the hub being loose on the shaft after properly torqued.
d) Describe what the solutions are.
For the rear cone bottoming corrective actions taken are to removed up to 1/16 inch from
the apex of the cone with sandpaper.
For the front cone bottoming corrective action that should be taken is add shim at the rear
cone no more than 1/8 inch thickness behind the rear cone.
A minimum of 70% contact on both rear and front cone. Using only Prussian blue.
2. State the cause of aircraft propeller vibration, your answer should cover the possible and
probable cause the vibrations. And discuss the solution.
The normal causes of aircraft propeller vibration are propeller blade imbalance, propeller
blades not tracking, and vibration in propeller blade angle settings. The solution to this is the
propeller blade tracking is to be checked and then the low-pitch blade angle settings to
determine if it is the cause of vibration. If the propeller blade tracking and the low angle
setting are incorrect, the propeller is statically or dynamically unbalanced. It should be
replaced or rebalanced by the manufacturer.
3. Refer to the Jeppessen A & P technician power plant text book under the Sub Chapter title Pratt
& Whittney PT 6. Describe about the OVERSPEED GOVERNOR
a. Purpose.
Act as a backup in the event of primary governor failed to control the propeller speed in
normal operating speed.
b. Construction.
Speeder-spring preset by the manufacture NO FIELD ADJUSTMENT required.
When propeller speed above the predetermined value, oil will be dumping and returned
to the Reduction gearbox.
Another safety feature to prevent propeller over-speed condition a fuel topping
governor incorporated with PT 6.
It senses the propeller speed, in the event of over-speed the governor dumping a
portion of bleed air from the FCU to reduce fuel flow to the engine.
c. Operation.
Similar to other governor, constant-speed units on a single-engine aircraft use oil
pressure to increase the pitch. If the CSU fails, the propeller will automatically return to
fine pitch, allowing the aircraft to be operated at lower speeds. By contrast, on a multi-
engine aircraft, the CSU will typically use oil pressure to decrease the pitch. That way, if
the CSU fails, that propeller will automatically feather, reducing drag, while the aircraft
continues to be flown on the good engine.
4. Referring to the above diagram explain the feather operation.
1. Presses and hold the feathering button.
2. Electrical pump start and pump pressure to the dome assembly.
3. Oil flow through the distributor valve to the forward side of the piston.
4. Blade start rotates out of feather position.
5. Propeller start windmill and propeller start up.
6. Released the feather button.
7. As safety feature if the feather button still depressed.
8. At the oil pressure exceed 750 psi dome relief off seat after the rotating cam contact
with low blade angle stop.
