PREPARACION MEDIA

Which condition causes the APU to operate at 101% speed instead of 100%?. A. Ground electrical operation only. B. Main Engine Start (MES) demand. C. Oil servicing operation.

What is the primary function of the APU Electronic Control Unit (ECU)?. A. Control and monitor all APU functions. B. Regulate hydraulic pressure. C. Control landing gear extension.

How many mounts support the APU installation?. A. Two. B. Three. C. Four.

What feature of the APU wire harness minimizes electromagnetic interference?. A. Aluminum conduit. B. Fiber-optic links. C. Shielded twisted-pair conductors.

Why must the APU intake door be fully open before engine start can continue?. A. To cool the gearbox. B. To allow ECU start sequencing and airflow. C. To energize the generator.

Which EICAS message may appear when commanded and actual intake door positions differ for more than 60 seconds?. A. APU DOOR. B. LOW OIL PRESSURE. C. GEN FILTER.

What is the primary purpose of gearbox pressurization at altitude?. A. Improve combustion efficiency. B. Prevent oil foaming. C. Increase generator speed.

Above approximately what altitude does gearbox pressurization become necessary?. A. 10,000 ft. B. 18,000 ft. C. 30,000 ft.

What is the oil reservoir capacity of the APU gearbox?. A. 4.2 quarts. B. 8.0 quarts. C. 6.2 quarts.

What pressure does the oil pressure regulator valve maintain?. A. 65 psid. B. 35 psid. C. 200 psid.

Which APU section converts fuel and air energy into shaft horsepower?. A. Gearbox. B. Power section. C. Load compressor.

What is the normal APU main shaft speed?. A. 39,850 RPM. B. 12,000 RPM. C. 25, 170 RPM.

Which gearbox-driven accessory normally operates at approximately 12,000 RPM?. A. Cooling fan. B. Starter motor. C. APU generator.

What is the primary function of the fuel flow divider?. A. Cool fuel before combustion. B. Separate primary and secondary fuel flows. C. Measure fuel quantity.

At what speed is the fuel flow divider solenoid energized?. A. 50% RPM. B. 7% RPM. C. 95% RPM.

What is the purpose of the combustor drain check valve?. A. Prevent hot starts by draining accumulated fuel. B. Increase combustor pressure. C. Improve fuel atomization.

At approximately what speed is ignition energized during start?. A. 95% RPM. B. 7% RPM. C. 42% RPM.

When does the starter motor cut out during a normal ground start?. A. 42% RPM. B. 95% RPM. C. 55% RPM.

How many inlet guide vanes regulate airflow into the load compressor?. A. 16. B. 24. C. 28.

Which pneumatic mode has the highest ECU priority?. A. ECS. B. In-flight. C. Duct Pressurization.

What is the normal fail-safe position of the surge valve?. A. Fully Open. B. Fully Closed. C. Mid Position.

Which sensor provides pressure altitude information to the ECU?. A. LCIT Sensor. B. EGT Thermocouple. C. P2 Sensor.

How many thermocouple assemblies are used to measure APU EGT?. A. Four. B. Two. C. Eight.

A REVERSE FLOW protective shutdown is most directly associated with which condition?. A. Compressor surge/backflow detection. B. Low oil level indication. C. Generator overload.

What is the main purpose of the cooling fan?. A. Pressurize the pneumatic manifold. B. Cool the compartment and oil cooler. C. Ventilate the flight deck.