2A651 Edition2 Volume 4

The barrel of the 54H60-117 propeller subassembly is responsible for transmitting the engine torque to the propeller blades.

The "C" in the engine number GTCP 165 indicates that the engine provides compressed air.

The pneumatic air bled from the small gas turbine engine cannot be used to inflate aircraft tires because the air bled from the engine is not pressurized enough to inflate the tires. It may not have the required pressure and volume to properly inflate the tires, which need a higher pressure to maintain their shape and support the weight of the aircraft.

The centrifugal twisting moment is the force that is used during pitchlock of the 54H60-117 propeller to prevent the blades from decreasing pitch. This twisting moment is generated by the centrifugal force acting on the rotating propeller blades, which counteracts any tendency for the blades to decrease their pitch angle. This ensures that the blades maintain their desired pitch setting during operation.

When the GTCP 165 engine is shut down, the fuel shutoff solenoid valve closes to ensure that the fuel flow is terminated. This valve is responsible for controlling the flow of fuel and shutting it off completely when the engine is not in operation.

The barrel of the 54H60-117 propeller subassembly carries high centrifugal loads created by the propeller blades. The barrel is a structural component that supports the blades and transfers the centrifugal forces to the rest of the propeller assembly. It is designed to withstand the high rotational speeds and forces generated during operation.

Synchrophasing is a technique used in multi-engine aircraft to ensure that all propellers rotate at the same speed. By maintaining the optimum blade phase angle relationship, the synchronization system adjusts the propeller speed to match each other. This helps to reduce vibrations and noise caused by propellers rotating at different speeds, resulting in smoother operation and improved performance of the aircraft.

Returning the pilot valve to the center position after correcting an overspeed condition on the 54H60-117 propeller will result in the system being back on-speed. This means that the propeller will return to its normal operating speed and the overspeed condition will be resolved.

The deicer contact ring holder is responsible for providing electrical circuits between the brush block assembly and the deicing elements of the blade assemblies. It serves as a connection point for the electrical system, allowing the power to flow from the brush block assembly to the deicing elements, ensuring their proper functioning.

During normal propeller operation, the output of the main pressure and main scavenge pumps is used on the 54H60-117 propeller.

During propeller static operation on the 54H60-117 propeller, the auxiliary pressure pump and the auxiliary scavenge pump are used.

The feather actuating valve assists the feather solenoid valve with the hydraulic positioning of the feather and pilot valves. It helps in controlling the movement and position of the valves, ensuring proper feathering of the propeller. The high pressure relief, standby, and backup valves are not directly involved in this specific function.

On a GTCP 165 engine oil system, air that leaks past various oil seals exits through the vent system. The vent system is designed to release any excess pressure or trapped air in the oil system. This helps to maintain proper oil pressure and prevent any damage or malfunctioning of the system. The vent system ensures that any air that leaks past the oil seals is safely released, allowing the oil system to function effectively.

When the main filter becomes clogged on the 54H60-117 propeller, the bypass valve opens to ensure that there is continued flow. The bypass valve allows the fluid to bypass the clogged filter and continue flowing through the system, preventing any disruptions or damage that could occur due to a lack of fluid flow.

During a normal start on a GTCP 165 engine, the igniter plug continues firing until the engine rotation in rpm reaches 95 percent. This means that the igniter plug will keep firing until the engine is almost at full speed, ensuring a smooth and successful start. Firing the igniter plug helps to ignite the fuel-air mixture in the engine, allowing it to start and reach the desired speed.

The purpose of the 54H60-117 propeller pitchlock assembly is to prevent engine overspeed due to a loss of hydraulic pressure. This means that if there is a loss of hydraulic pressure, the propeller pitchlock assembly will engage and prevent the propeller from spinning too fast, which could cause an overspeed condition. It is not related to loss of oil pressure or the flow of hydraulic fluid to the pilot valve.

The beta feedback shaft delivers the actual propeller blade angle from the blade to the control assembly.

The rotating cam on the 54H60-117 propeller is allowed to turn while the stationary cam remains fixed due to the presence of ball bearings. Ball bearings are designed to reduce friction and allow smooth rotation between two moving parts. In this case, the ball bearings enable the rotating cam to move freely while the stationary cam remains in its fixed position.

The impeller wheel and two turbine wheels in the turbine section of the GTCP 165 engine are connected by couplings on a common shaft. This means that the three wheels are linked together through a mechanism that allows them to rotate together. This arrangement ensures that the energy generated by the impeller wheel is efficiently transferred to the turbine wheels, enabling the engine to function properly. A gear reduction gearbox, helical splines, or tie bolts would not provide the same level of connection and synchronization between the wheels.

The low pitch stop assembly on the 54H60-117 propeller prevents the propeller from going into the beta range when the throttle is positioned in the alpha range. This is important because the beta range is used for reverse thrust, and it is undesirable for the propeller to enter this range while the throttle is in the alpha range. The low pitch stop assembly ensures that the propeller remains in the appropriate range of blade angles based on the position of the throttle.

The correct answer is turbine plenum. In a GTCP 165 engine, the load control system requires air for its operation. This air is extracted from the turbine plenum. The turbine plenum is a chamber located after the turbine section of the engine, where high-pressure and high-temperature gases are present. This location allows for the extraction of air that can be used for various purposes, such as controlling the load in the engine.

In the synchrophasing governing mode, the slave propeller blades are in the correct phase angle position. This means that they are aligned properly with the master propeller blades. When the phase angle position is correct, there is no phase error voltage, resulting in a phase error voltage of 0.

If the R391 Dowty propeller loses hydraulic pressure, the counterweights installed at the root of each propeller blade would drive the propeller blades towards the "Feather" position. Feathering the propeller means adjusting the blade angle to minimize drag and allow for a controlled descent or landing in the event of an engine failure.

When attempting to unfeather the 54H60-117 propeller in flight, the throttle must be positioned above FLT IDLE. This means that the throttle can be at any position higher than the flight idle position.

The correct answer is a four-wheel trailer. This means that when the SGT engine is used for ground operation, it can be installed on a four-wheel trailer.

The pitchlock control cam is the component that mechanically holds the stationary and rotating pitchlock ratchets apart during reversing and unfeathering operations on the 54H60-117 propeller. This cam ensures that the propeller blades are locked in the desired position during these operations.

When the backup valve is opened on the 54H60-117 propeller, the hydraulic pressure routed to the governor pilot valve is used for the operation of reversing the propeller.

The correct answer is "Check." On the 54H60-117 propeller, the check valve opens to allow the output of the standby pump to combine with the output of the main pump. This valve ensures that the hydraulic fluid flows in one direction and prevents any backflow.

During the manufacturing process of the 54H60-117 propeller, a beveled thrust washer is installed on the blade before the blade butt is formed. This component helps to distribute the thrust load evenly and reduce friction between the blade and the propeller hub. It ensures smooth operation and efficient performance of the propeller system. Slip rings, microadjusting rings, and roller thrust bearings are not relevant to this specific step in the manufacturing process.

The auxiliary pressure pump is used to feather or unfeather the propeller during static propeller operation on the 54H60-117 propeller.

The compensating network in the synchrophaser unit allows the speed bias motor to correct a change in rpm of 2%.

Constant speed can only occur when the throttle is positioned from FLT IDLE to TAKE OFF. This means that the throttle needs to be adjusted to a specific setting in order to maintain a consistent speed. The other options, RVS to FLT IDLE, RVS to GND IDLE, and GND IDLE to FLT IDLE, do not indicate a specific throttle position that would result in constant speed.

The oil pressure switch is responsible for shutting down the GTCP 165 engine if the oil pressure drops below the safe minimum operating limit. This switch is designed to monitor the oil pressure and act as a safety measure to protect the engine from potential damage caused by low oil pressure. When the switch detects a drop in oil pressure, it sends a signal to shut down the engine, preventing any further operation until the issue is resolved.

The 54H60-117 propeller governor speeder spring tension positions the pilot valve to maintain a range of 109 to 113% RPM in the beta range.

The master synchrophaser board contains a master channel and a slave channel. The question is asking which numbers correspond to the master and slave channels. The answer is No. 2 and No. 3, indicating that the master channel is No. 2 and the slave channel is No. 3.

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The throttle is responsible for coordinating the propeller blade pitch and engine fuel flow in the controllable pitch range. The propeller blade pitch determines the angle at which the blades cut through the air, affecting the amount of thrust generated. The engine fuel flow controls the amount of fuel being supplied to the engine, which in turn affects the engine power output. By coordinating these two variables, the throttle ensures optimal performance and efficiency of the propeller system.

The PCBS (Propeller Control Boost System) switch, located in the valve housing, is opened by a cam when the propeller blade angle is between 81° to 85°. This switch is part of the propeller control system and is responsible for controlling the boost pressure applied to the propeller blades.

The correct answer is Beta tube. The Beta tube is a component of the R391 Dowty propeller that is responsible for routing engine oil to and from the cylinder and piston. It plays a crucial role in lubricating and cooling the engine, ensuring its smooth operation. The other options mentioned, GBE valve, PUAD, and GMAD, are not related to routing engine oil in the R391 Dowty propeller.

The oil system on a GTCP 165 engine is of the wet sump design. In a wet sump design, the engine's oil is stored in a reservoir located within the engine's crankcase. This design allows for easier access and maintenance of the oil system, as the oil is readily available within the engine rather than being stored in a separate oil tank.

During normal GTCP 165 engine shutdown, the 110-percent circuit trips to stop the engine. This circuit is responsible for monitoring the engine's performance and ensuring it does not exceed its maximum operating capacity. When the engine reaches 110 percent of its maximum capacity, the circuit automatically trips, triggering the shutdown process.

Normal and synchrophasing are propeller governing modes that add more functionality to the basic mechanical governing mode. Normal mode is used for controlling propeller speed during normal operations, while synchrophasing mode is used to synchronize the propellers on multi-engine aircraft to reduce noise and vibration. These modes enhance the performance and efficiency of the propeller system beyond the basic mechanical governing mode.

The beta range indication display on the coordinator for the 54H60-117 propeller is from 0 degrees to 34 degrees.

The correct answer is "Backplate." The backplate is a part of the R391 Dowty propeller assembly that provides an aerodynamic fairing over the aft section of the hub. It helps to streamline the propeller assembly and improve its overall performance.

The correct answer is "Speed set." During alpha range operation on the 54H60-117 propeller, the speed set cam changes the speeder spring tension. This adjustment allows the governor pilot valve to maintain 100 percent engine speed.

During an overspeed condition in the alpha range on the 54H60-117 propeller, the flyweights move the governor pilot valve to meter hydraulic fluid. This action will increase the blade angle.

The correct answer is "Beta set." On the 54H60-117 propeller, the cam that schedules a desired blade angle in the beta range is the Beta set cam. This cam controls the pitch of the propeller blades in the beta range, allowing for efficient reverse thrust and deceleration of the aircraft.

When the standby pump output is not required on the 54H60-117 propeller, it is routed to the pressurized sump. This means that the excess fluid from the standby pump is directed to a pressurized sump rather than being used elsewhere in the system.

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The movable wedge is responsible for moving the stop levers on the low pitch stop outward on the 54H60-117 propeller. The movable wedge is a component that is designed to transmit hydraulic pressure to the stop levers, causing them to move in the desired direction. This allows for control and adjustment of the pitch of the propeller blades.