CDC 2A651H Volume 5

A pilot can operate a T700 turboshaft engine on contingency power for 2.5 minutes.

The first step in troubleshooting a T700 turboshaft engine is to check the aircraft forms. This is important because the aircraft forms contain valuable information about the history and maintenance of the engine, which can help identify any previous issues or recurring problems. By reviewing the aircraft forms, the technician can gain insight into the engine's maintenance history and potentially find clues that can guide the troubleshooting process.

An auxiliary power unit (APU) is considered a dry sump system if the oil is not stored within the engine itself. In a dry sump system, the oil is stored in a separate reservoir or tank, rather than being contained within the engine. This design allows for better oil control and lubrication, as well as improved cooling. By separating the oil storage from the engine, a dry sump system can provide a more efficient and reliable lubrication system for the APU.

The correct answer is "only when the filter bowl and element are removed." This means that the oil filter bypass indicator button can only be reset when the filter bowl and element have been taken out. This suggests that the indicator button is directly connected to the filter bowl and element, and resetting it requires their removal.

The APU (auxiliary power unit) is a self-contained power source that can be used to start the aircraft's main engines, provide electrical power, and operate various systems while the aircraft is on the ground or in flight. It is designed to be independent of the aircraft's main engines and can be started and operated regardless of whether the aircraft is on the ground or flying. This makes it a versatile power source that can be used in various situations.

If the auxiliary power unit (APU) of an H-60 helicopter fails to light-off, the hydraulic accumulators can be manually recharged using a hand pump. This indicates that the hand pump is the appropriate tool to use in such a situation.

The prime/boost pump is responsible for supplying fuel under pressure to the H-60 helicopter's auxiliary power unit (APU) during high-altitude operations. This pump ensures that the APU receives a consistent flow of fuel, which is crucial for its proper functioning at high altitudes.

The variable stators on the T700 turboshaft engine are actuated to the maximum open position at maximum power. This means that the stators are adjusted to allow the maximum amount of air to flow through the engine, optimizing its performance and power output. By opening the stators fully, the engine can generate the maximum amount of thrust, making it more efficient and effective in high-power situations.

The thermocouple resistor is the correct answer because it is the component that calibrates the exhaust gas temperature (EGT) indicator to the thermocouple. A thermocouple is a device that measures temperature by generating a voltage proportional to the temperature difference between its two junctions. The thermocouple resistor is responsible for ensuring that the EGT indicator accurately reflects the temperature measured by the thermocouple.

The correct answer is A and B because the question asks which sumps are used for the emergency oil system on the T700 turboshaft engine. This means that multiple sumps are involved in the emergency oil system, and the correct answer is A and B, indicating that sump A and sump B are both used for this system.

When any spike or fluctuation in engine indications occurs during T700 turboshaft engine operation, the recommended action is to disconnect, clean, and inspect the electrical connectors. This is because spikes or fluctuations in engine indications can be caused by poor electrical connections, which can lead to inaccurate readings or malfunctions. By disconnecting, cleaning, and inspecting the electrical connectors, any potential issues with the connections can be identified and resolved, ensuring accurate engine indications and proper engine operation.

The T700 turboshaft engine's electrical filter bypass sensor senses differential fuel pressure, which causes the valve to open. Differential pressure refers to the difference in pressure between two points, in this case, the pressure difference across the fuel filter. When the sensor detects a significant difference in pressure, it triggers the valve to open and bypass the filter, allowing fuel to flow through. This helps maintain proper fuel flow and prevents clogging or damage to the engine.

The power turbine module extracts most of the energy from the exhaust gases for output power. This turbine is responsible for converting the high-velocity gas flow into mechanical energy, which is then used to drive the rotor system and generate power. Unlike the other modules mentioned, the power turbine is specifically designed to maximize energy extraction from the exhaust gases, making it the correct answer.

The T700 turboshaft engine oil tank is located internally in the main frame. This means that the oil tank is situated within the main frame of the engine, rather than being located externally or in the swirl frame. This internal placement ensures that the oil is securely stored within the main frame, allowing for efficient lubrication and cooling of the engine components.

The T700 turboshaft engine uses an alternating current (AC)-powered, capacitor-discharge type ignition system. This means that the ignition system is powered by AC current and uses capacitors to store and discharge electrical energy to generate the spark needed for ignition. This type of ignition system is commonly used in gas turbine engines like the T700 to provide reliable and efficient ignition for combustion.

The correct answer is LOCKOUT. The LOCKOUT position on the power control lever of the H-60 helicopter provides manual control over the gas generator speed. This position allows the pilot to manually adjust the speed of the gas generator, which is an essential component of the engine. By selecting the LOCKOUT position, the pilot can override any automatic control systems and have direct control over the gas generator speed. This level of control is important for certain flight conditions or emergency situations where manual control is necessary.

The electronic sequence unit (ESU) on an H-60 helicopter takes a reading of the major auxiliary power unit's (APU) parameters every 50 milliseconds. This implies that the ESU is constantly monitoring and recording the APU's parameters at a very high frequency, allowing for real-time monitoring and quick response to any changes or issues with the APU. This level of frequency ensures that any potential problems can be detected and addressed promptly, ensuring the safety and efficiency of the helicopter's operation.

The compressor bleed air supplied by small gas turbine (SGT) engines is not used for heating the fuel supplied to the engines. Compressor bleed air is typically used for various purposes such as air-conditioning, pressurizing the aircraft, and starting the main engines. However, heating the fuel supplied to the engines is not one of its uses.

The governor is the component of the auxiliary power unit (APU) that takes over engine speed control after the APU has accelerated above 95 percent revolutions per minute (rpm). It is responsible for maintaining a consistent and safe speed for the engine. The fuel pump is not directly related to engine speed control, and the acceleration control is responsible for controlling the rate of acceleration, not the engine speed. The pneumatic thermostat is unrelated to engine speed control in this context.

A new Health Indicator Test (HIT) baseline must be established during the initial ground run of a T700 turboshaft engine performance check. This is because the initial ground run provides an opportunity to assess the engine's performance and establish a baseline for future reference. It allows technicians to identify any potential issues or abnormalities before the engine is put into service. Establishing the HIT baseline during this stage ensures that accurate measurements and comparisons can be made during subsequent performance checks.

Fuel flow (Wf) is not required for calculating T700 turboshaft engine performance because fuel flow is a result of engine performance, not a parameter used to calculate it. Pressure altitude (PA), free air temperature (FAT), and turbine gas temperature (TGT) are all necessary factors in determining engine performance as they affect the engine's efficiency and power output. However, fuel flow is a measurement of the amount of fuel consumed by the engine, which can be determined once the engine performance is known.

The correct answer is "turbine torus". After combustion, the hot gases flow through the bottom of the C-130 aircraft's APU combustion can and into the turbine torus.

A periodic inspection on T700 turboshaft engines must be performed after 500 flight hours. This is the recommended timeframe for ensuring the engines are in good working condition and to identify any potential issues or maintenance needs. It is important to adhere to this schedule to maintain the safety and efficiency of the engines.

The correct answer is 90 because the H-60 helicopter auxiliary power unit (APU) is rated at this horsepower.

During T700 turboshaft engine operation, the history counter hours indicator stops when the gas generator (Ng) turbine rotor speed drops below 55 percent. This means that the indicator only records the hours of operation when the turbine rotor speed is above 55 percent.

The correct answer is battery bus. The auxiliary power unit's control switch receives electrical power from the battery bus. This means that the APU can be powered even if the AC primary bus, DC primary bus, or DC secondary bus are not functioning or unavailable. The battery bus provides a direct source of power to the APU's control switch, ensuring that it can be operated independently of other electrical systems on the helicopter.

When the power available spindle (PAS) is advanced to 26 degrees during a T700 turboshaft engine start, it opens the fuel stopcock. This means that the fuel supply to the engine is allowed to flow, enabling the combustion process to begin. The opening of the fuel stopcock is a crucial step in starting the engine and providing the necessary fuel for ignition and subsequent operation.

The correct answer is seven-element gerotor. A gerotor is a positive displacement pump that uses an inner and outer rotor to create chambers for fluid flow. The number of elements refers to the number of lobes on the rotors. In this case, the T700 turboshaft engine uses a seven-element gerotor pump for oil circulation.

The air turbine motor is the component that contains the AC generator on C-130 type aircraft with a gas turbine compressor (GTC). The air turbine motor is responsible for converting the energy from the GTC into mechanical energy, which is then used to drive the generator and produce alternating current. Therefore, the air turbine motor is the correct answer in this case.

The correct answer is the opening rate of the load control valve. The auxiliary power unit (APU) load control valve is responsible for controlling the flow of air to the APU. The rate control feature of the valve allows for the adjustment of the opening rate, which determines how quickly the valve opens to allow air to flow. This feature is important for maintaining proper control and regulation of the APU's operation.

The correct answer is fuel shutoff solenoid valve. When the engine starts to overspeed and the fuel control and pump assembly governor has not metered fuel sufficiently to reduce the speed during the APU's operation, the 110 percent switch in the multiple centrifugal switch assembly opens the circuit to the fuel shutoff solenoid valve. This valve is responsible for shutting off the fuel supply to the engine, effectively stopping the engine from further overspeeding.

The scroll vanes of the T700 turboshaft engine are anti-iced by using hot scavenge oil. This means that the oil that is scavenged from the engine, which is already hot, is used to prevent ice formation on the scroll vanes. The hot oil is directed to the scroll vanes, where it heats up the surfaces and prevents ice from forming. This method is effective in ensuring that the scroll vanes remain ice-free and maintain optimal performance during operation.

The correct answer is "one-piece assembly with seven, single-immersion probes." This means that the thermocouple harness on the T700 turboshaft engine is made up of a single piece and includes seven probes that are designed for single immersion. This suggests that the harness is designed to measure temperature at seven different points within the engine using probes that are immersed in the engine's components.

The correct answer is "Onboard." In the H-60 helicopter, the onboard aircraft fire extinguisher is wired directly to the aircraft battery. This means that it is directly connected to the battery for power supply, ensuring that it has a constant source of power in case of an emergency.

The C-130 aircraft's auxiliary power unit (APU) turbine section converts the hot gases produced by the combustion section into mechanical energy. This mechanical energy is then used to power various systems and components of the aircraft, such as generators, pumps, and compressors.

The correct answer is 6. This means that there are 6 oil scavenge screens located on the T700 turboshaft accessory gearbox.

During a T700 turboshaft cold engine start, the cold oil relief valve opens and directs excess oil to the accessory gearbox. The accessory gearbox is responsible for driving various accessories such as the generator, hydraulic pump, and fuel control unit. By directing the excess oil to the accessory gearbox, it ensures proper lubrication and cooling of the gearbox components during the start-up process.

The T700 turboshaft engine's hydromechanical unit (HMU) does not have a fuel discharging system. This means that the HMU is not responsible for releasing or discharging fuel from the engine. Instead, it is likely that the fuel is delivered to the engine through a different system or component.

The control system operation on the T700 turboshaft engine is split functionally between the hydromechanical unit (HMU) and the digital electronic control (DEC) unit. This means that each unit has its own specific functions and responsibilities within the overall control system. The HMU is responsible for controlling the fuel flow and other mechanical aspects of the engine, while the DEC unit is responsible for managing the digital electronic controls and monitoring various engine parameters. By splitting the control system operation functionally, the engine can benefit from the strengths of both the HMU and DEC units, resulting in efficient and reliable engine performance.

The correct answer is 95 percent. Within the multiple centrifugal switch assembly, the switch that opens a circuit to stop the C-130 aircraft auxiliary power unit's (APU) ignition unit is the one that activates at 95 percent. This switch is designed to prevent any potential damage or malfunction by cutting off the ignition unit when the APU reaches this level of speed.

The sequencing oil pressure switch is responsible for completing circuits to the fuel shutoff valve and the ignition unit once the oil pressure in the C-130 aircraft auxiliary power unit (APU) reaches approximately 2 to 3 psi. This switch ensures that the necessary components are activated in the correct sequence for the APU to operate effectively.

Autorotation is a maneuver used in helicopters to safely land in the event of an engine failure. During autorotation, the helicopter's rotor blades are allowed to spin freely, generating lift from the airflow. To enter autorotation, the pilot needs to lower the collective pitch, which decreases the angle of attack of the rotor blades and reduces the overall lift. This allows the helicopter to descend smoothly and maintain control. Therefore, the correct answer is lowering collective pitch during descent.

The T700 turboshaft engine oil filter bypass sensor switch is located on the forward side of the accessory gearbox.

The T700 turboshaft engine history counter contains 4 indicators.

The correct answer is three because the question is asking about the number of systems that make up the T700 turboshaft engine control system. Since the answer is three, it means that there are three separate systems that work together to control the engine.

The correct answer is the Acceleration control diaphragm. During the start and acceleration of the C-130 aircraft's auxiliary power unit (APU), the thermostat bleeds air pressure away from the acceleration control diaphragm. This helps regulate and control the acceleration of the APU.

The correct answer is Three. The compressor variable geometry system of the T700 turboshaft engine has three actuating rings. These actuating rings are responsible for adjusting the compressor blades to optimize engine performance at different operating conditions. Each actuating ring controls a different set of compressor blades, allowing for precise control of airflow and compression within the engine.

The correct answer is 51 °C. The explanation for this is that the auxiliary power unit (APU) on an H-60 helicopter can be operated continuously up to temperatures of 51 °C. This means that as long as the temperature does not exceed 51 °C, the APU can be used even if the engines and rotors are not running.

The correct answer is compressor discharge pressure and fuel pressure. The acceleration control valve in the C-130 aircraft's auxiliary power unit (APU) uses these two inputs to determine the proper fuel-flow to the atomizer during acceleration. By monitoring the compressor discharge pressure and fuel pressure, the valve can adjust the fuel-flow accordingly to ensure optimal performance and efficiency of the APU.

The hydromechanical unit (HMU) actuating system on the T700 turboshaft engine opens the start bleed valve (SBV) when gas generator (Ng) turbine rotor speed goes below 87 percent.