Motores-APU

Which maintenance action is necessary after shutting down the APU using the P40 APU SHUTDOWN switch?. The APU start sequence must be reinitialized using the APU control switch momentarily to START/ON. The APU ECU must undergo a Self-Test BITE procedure to reset internal protective shutdown flags. The battery switch in the flight deck must be cycled OFF and ON before subsequent APU startup attempts.

Which component provides access for manual turning of the N2 rotor for borescope inspections?. The N1 speed sensor pad, accessible with the right thrust reverser half fully open. A square drive pad located on the accessory gearbox, used for manual rotation or rigging. The pneumatic starter V-band clamp assembly located on the aft side of the accessory gearbox.

In case of simultaneous electrical and pneumatic demands, how does the ECU prioritize APU operation?. The ECU reduces the pneumatic output as necessary to prevent exceeding the specified APU EGT limitations. Electrical output is reduced first, as pneumatic demands have higher operational priority above 18,000 feet. The ECU increases the APU speed to 101% RPM to meet both loads efficiently, regardless of EGT limits.

What is the approximate maximum altitude for APU pneumatic power availability in flight?. Up to approximately 17,500 feet, which is the maximum altitude, for the main engine starts, using APU air. Electrical power is available at any altitude, pneumatic power is restricted only above 35,000 feet. Up to approximately 17,500 feet, allowing air supply for environmentalcontrol systems.

The High Pressure Compressor (HPC) section of the core module is characterized by. Five stages of compression, including the fan rotor and four booster stages, driven by the N1 rotor. A single-stage axial flow turbine section coupled directly to the Low Pressure Turbine spool. A 14-stage compressor section, where the inlet guide vanes and first five stages utilize Variable Stator Vanes (VSV).

Which voltage is utilized by the ECU to energize the APU Fuel Shutoff Solenoid Valve?. 28 V dc power supplied by the ECU, causing the solenoid valve to open for fuel supply. 400 Hz three-phase ac power derived from the APU generator output. 115 V ac primary power, converted internally by the ECU to sustain continuous combustion.

The APU power section consists of which primary components?. The load compressor section, the power section drive shaft, and the accessory gearbox unit. A single shaft gas turbine engine, coupled directly to the load compressor and the accessory gearbox. A three stage axial turbine, a reverse flow annular combustor, and a two stage centrifugal compressor.

The minimum required N2 speed percentage for the EEC to receive power from the dedicated Control Alternator is: Above 45%, ensuring power delivery even if one phase of either or both windings fails. Above 11%, continuing to meet power requirements until N2 decreases below 9%. Above 50%, initiating the automatic cutout of the pneumatic starter control valve actuator.

During starting, until N2 reaches 50%, the holding coil keeps the ignition/start control switch in which position?. GND position, energizing the pneumatic starter control valve and enabling ignition. FLT position, enabling dual ignition for the in-flight start envelope if necessary. CONT position, ensuring continuous ignition enablement regardless of N2 speed.

Which specific fuel nozzles are identified by blue bands and supply a richer primary flow to prevent-flameout?. Nozzles 9 through 22, located under the engine for better gravity feed during low flow rates. Nozzles 15 and 16, typically having larger primary flow passages than theother 28 nozzles. Nozzles 1 and 30, located at the 12:00 position of the combustion chamber manifold.

The thrust reverser interlock actuator prevents the movement of forward thrust power levers above idle until the translating cowls are stowed by at least what percentage?. At least 60% deployed, permitting the reverse thrust lever to increase reverse thrust. At least 20% stowed, which is the deployment threshold to remove the interlock actuator ground. At least 80% stowed, ensuring the fan discharge path is completely blocked for forward thrust.

The Variable Bypass Valves (VBV) fail-safe to which position?. Fully closed, to ensure maximum core flow and prevent engine stall during low power settings. Fully open, diverting LPC primary discharge air to the secondary flow path to prevent stall. Fully modulated, allowing the EEC to calculate substitute position values from the VSV actuators.

Which type of sensor element is used in the Fan Inlet Temperature (T12) sensor?. A Resistive Thermal Device (RTD), where resistance is directly proportional to the inlet airflow temperature. A variable reluctance unit, sending an electrical analog signal to EICAS to calculate pressure. A chromel-alumel thermocouple, typically used for high temperature measurement like EGT (T49).

Which component provides a third level of safety to prevent uncommanded deployment of the thrust reversers in flight?. The Directional Pilot Valve (DPV), which changes the directional control valve position in the CDU. The Thrust Reverser Pressure Regulating and Shutoff Valve (T/R PRSOV), which isolates the pneumatic system. The electro-mechanical brakes (TRAS brake), which lock the flexible drive cable at the upper actuator.

What is the official designation for the pressure sensor located at the HPC Inlet (Fan Hub Outlet)?. P3, indicating the HPC discharge pressure (CDP) before combustion occurs. P14, measuring the fan discharge pressure of the secondary air flow path to the nozzle. P25, representing the pressure measurement at the inlet of the High Pressure Compressor.

The Core Compartment Cooling Valve (CCCV) is typically closed during which power settings and altitudes, to maximize efficiency? I. The valve is closed at high power and high altitudes to conserve primary air and maximize engine efficiency. The valve is closed at low power and low altitudes to maximize cooling air flow over the gearbox. The valve is open at all power settings to ensure sufficient cooling of the high pressure compressor case.

What is the function of the Fan Isolation Valve located in the APU air system?. It closes off the supply air leading to the cooling fan only in the event that an APU fire is detected. It manages the PCD2 buffer air flow selected by the shuttle valve for the cooling fan and compressor bearings. It allows cooling fan air to flow through the oil cooler and into the APU compartment when PCD2 pressure is met.

When both thrust reverser halves are fully deployed, what EICAS indication is typically shown on the upper display?. The indication is inhibited in-flight by the air/ground logic system. A yellow REV indication appears above the N1 digital display. A green REV indication appears above the N1 digital display.

The N1 speed sensor measures rotation using ferromagnetic teeth passing its tip. How many teeth are on the fan shaft?. 38 ferromagnetic teeth, with one taller tooth to aid in tracking vibration for balancing purposes. 7 bearing sets, which are housed inside three oil sumps: A, B+C, and D sumps for lubrication. 28 ferromagnetic teeth, with one smaller tooth to aid in tracking vibration for balancing purposes.

Where is the Engine Oil Temperature Sensor (TEO) located within the engine system?. It is integral to the oil quantity transmitter mounted on top of the oil tank, providing dual redundancy. It is situated in the scavenge oil return path before the scavenge oil cooling and filtration components. It is situated downstream of the scavenge oil filter, measuring temperature before oil returns to the tank.

What is the total volume of the engine oil tank when it is properly serviced?. 4 U.S. quarts (15 liters). 6.6 U.S. gallons (25 liters). 8 U.S. gallons (30.5 liters).

What is the correct sequence for closing the major engine cowlings?. Close the thrust reverser halves first, ensuring the latch ring assembly is engaged before closing core cowls. Close the core cowl panels first, then the thrust reverser, followed by the fan cowl panels. Close the fan cowl panels first, then the core cowl panels, and finally the thrust reverser halves.

Which major engine components are accessed when opening the thrust reverser halves?. Components located on the low pressure compressor case and the engine fan frame structure. The engine oil tank and the main fuel pump pad located on the forward face of the accessory gearbox. Components located on the high pressure compressor case and the accessory gearbox unit.

What component location provides access to service the engine oil tank without opening the main fan cowl panel ?. Through an access door located on the right fan cowl panel for convenient oil servicing. Via the left core cowl panel, which houses the high pressure fuel shutoff valve HPSOV. Through the accessory gearbox pad, requiring removal of the IDG oil filter element.

What is the primary function of the Fan Cowl Chine?. It acts as an acoustic liner segment, reducing the overall engine noise level of the fan air exhaust. It improves the airplane aerodynamic characteristics, particularly during low air speed operations. It houses the pressure relief panel designed to open at a specified differential pressure.

What is the opening pressure differential for the relief valve in the Servo Fuel Heater to bypass blocked flow?. The relief valve opens at 23 psid, if the fuel passage through the heater tubes is blocked. The relief valve opens at 60 psid, bypassing hot scavenge oil if the oil passage becomes blocked. The relief valve opens at 40 psid, allowing the bypass of scavenge oil around the filter element.

Which stage air from the HPC is used to cool the HPT stage 2 nozzles?. 14th stage HPC air, specifically used to cool the HPT first and second stage rotor blades. 7th stage HPC air, typically utilized for engine and aircraft pneumatics requirements. 11th stage HPC air, also used for HPT first stage nozzle cooling.

What does the appearance of the latched EICAS message APU OIL QTY signify?. The oil quantity is approximately 2 quarts below the full APU not running level, requiring servicing soon. The oil pressure is below 31 psig for 15.5 seconds, triggering an LOP protective shutdown and EICAS alert. The oil quantity is below 2.7 quarts (engine running), necessitating an immediate APU shutdown procedure.

Which pressure is utilized by the gearbox pressurization system to prevent oil foaming at high altitudes?. Power section second stage compressor discharge air (PCD2) is utilized to maintain gearbox pressure at 4 psi above ambient. Power section first stage compressor discharge air (PCD1) is utilized for pressure, maintaining 4 psi above ambient. Load compressor discharge air (LCDA) is utilized to supply buffer air for the compressor and cooling fan bearings.

What is the typical opening angle of the thrust reverser halves?. They are open to the 20 degree position for component access. They are held to the 60 degree position using flush-mounted tension latches. They are open to the 45 degree position with the thrust reverser translating cowls extended.

Which protective shutdown occurs if the ECU senses failure of both APU Monopoles (RPM)?. A FAILED SENSOR protective shutdown is initiated immediately by the ECU due to dual speed sensing failure. A NO ACCEL protective shutdown occurs because the ECU cannot control fuel flow without valid RPM data. A SLOW START protective shutdown is initiated after 30 seconds due to lack of an appropriate speed signal.

If the EEC detects a NO DISPATCH fault, which advisory message is displayed on EICAS?. L (R) ENG EEC MODE, indicating that the engine is operating in a soft or hard reversionary control mode. L (R) ENG LIM PROT, meaning the N1 thrust setting exceeds the maximum rating by 2% due to reversionary mode. L (R) ENG CONTROL, indicating a critical EEC or control system failure preventing dispatch.

The thrust reverser opening actuator contains an inlet fitting restrictor designed to limit the rate of closure to at least what duration?. The actuator ensures that the thrust reverser half takes at least 15 seconds to fully close. The opening actuator is equipped with a pressure relief valve set to open between 4350 and 4500 psig. The restrictor limits the closing rate to 30 seconds to prevent damage to the translating cowls.

What precaution must be taken before manually selecting the Hard Reversionary Control Mode to prevent possible engine overboosting?. The thrust levers must be pulled back to an intermediate position to reduce N1 command input. The thrust levers must be placed at the reverse idle detent position to engage the interlock actuator. The pilot must push the thrust levers forward to the maximum thrust position to calibrate N1 command.

Which two sources typically provide the necessary power for the Ignition Exciters?. The 28 V dc APU battery bus, with the main battery bus available through a diode circuit for redundancy. Normally the left and right 115 V ac buses, with the standby ac bus available as an alternative source. The dedicated control alternator windings (A and B), generating three- phase ac power for the EEC.

The N2 core shaft speed sensor provides an output signal to EICAS, AVM, and the N2 speed cards. Where is this sensor typically mounted?. On the fan frame strut, located at the 2:00 position, sensing the N1 rotor speed using ferromagnetic teeth. In the High Pressure Compressor (HPC) section, sensing speed for the N2 limit protection in the HMU. On the accessory gearbox, sensing core speed for the EEC, AVM, EICAS, and N2 speed cards.

The ignition lead cooling jacket is supplied with air from which engine system?. 14th stage HPC bleed air, used at low power settings for pneumatic starting. APU pneumatic supply duct, ensuring continuous airflow during engine starting phases. Fan air derived from the turbine case cooling duct, which also cools the igniter plug.

If the Scavenge Oil Filter Differential Pressure Switch closes, indicating impending bypass, what EICAS message appears?. L (R) ENG OIL TEMP, warning the crew that the scavenge oil temperature has exceeded the EEC limit. L (R) ENG OIL PRESS, which is a level B message for low oil pressure conditions. L (R) OIL FILTER, which is a level C message, appearing after a time delay if the pressure exceeds 33 psid.

The CDU position feedback transducer utilizes what type of sensor to convert the angular position of the rotor shaft into electrical signals for the EEC?. Torque Motor Metering Valve (TMMV), controlled electronically by the EEC for fuel flow regulation. Linear Variable Differential Transformer (LVDT), providing linear position signals to the EEC. Rotary Variable Differential Transformers (RVDT's), which convert the rotor shaft rotation (77° arc) into percent-of-deployment.

Which component controls fuel flow output from the Fuel Control Unit (FCU) to the combustor?. The Torquemotor Metering Valve, controlled by electrical current input from the Electronic Control Unit. The High Pressure Relief Valve, which protects the system from overpressurization above 950 psid. The Actuator Pressure Regulator, maintaining stable fuel pressure supplied to the Inlet Guide Vane Actuator.