PP 03

What should be done to an aircraft engine after the oil dilution system has been used for a season?. Replace spark plugs daily. Drain crankcase at each flight. Check filter screens daily until sludge/carbon disappear. Replace hydraulic lines.

What affects the density of air?. Temperature, moisture, pressure. Only humidity. Oil viscosity and RPM. Cowl flap position.

What causes a temperature drop in the throat of a carburetor while the engine is operating?. High RPM. Fuel vaporization and venturi pressure drop. Magneto timing. Ignition lag.

Is air drawn through the carburetor heat system filtered or unfiltered?. Always filtered. Always unfiltered. Filtered at high RPM only. Filtered during takeoff only.

Where does the heat come from in the carburetor heat system?. Engine oil cooler. Air taken from exhaust system area. Air taken from around the cylinders. Ram air scoop.

What effect does ram air taken in through an air scoop have on the performance of a naturally aspirated engine?. Reduces volumetric efficiency. Increases fuel consumption. Increases volumetric efficiency. Lowers compression ratio.

Where does the heat come from that is used in the alternate air system of a fuel-injected engine?. From the exhaust manifold. From the warmer air around the engine area. From the turbocharger compressor. From the ram-air scoop.

Where is manifold pressure measured from?. Between the carburetor venturi and throttle valve. In the intake manifold downstream of the exhaust. Between the throttle valve and the engine intake valves. From the air intake before the filter.

When carburetor heat is selected, what normally happens to engine RPM and manifold pressure?. RPM increases, manifold pressure increases. RPM decreases, manifold pressure increases. RPM increases, manifold pressure decreases. RPM decreases, manifold pressure decreases.

What effect does humidity have on the power output of an engine?. It increases power output due to cooler air. It reduces power output because humid air is less dense. No effect on performance. It increases exhaust gas temperature but not power.

On a two-speed internal supercharger, which blower is normally used for sea-level take-off?. High blower. Low blower. Reverse blower. Both simultaneously.

What is the purpose of the diffuser in an internal supercharger?. To increase the rotation speed of the compressor. To cool the compressed air. To decrease the velocity of air and increase its pressure. To reduce detonation in cylinders.

What is used to drive the compressor of a turbo-supercharger?. Engine crankshaft. Electric motor. Fuel pump. Exhaust gases.

How is turbocharger speed controlled in a general aviation aircraft?. By adjusting fuel flow. By the intercooler position. By the wastegate position. By carb heat application.

What are the three sections of a turbocharger?. Diffuser, casing, sump. Compressor, turbine, center housing. Intake, blower, exhaust. Governor, vane, scroll.

What type of bearings are used in a turbocharger?. Needle bearings. Roller bearings. Ball bearings. Plain bearings (floating).

In the turbocharger center housing, is the oil inlet hole larger or smaller than the outlet hole?. Smaller — to restrict flow. Larger — to ensure positive oil scavenge. Equal — to maintain balanced pressure. Random — depends on model number.

Where does the oil go after it leaves the turbocharger center housing?. Back to the oil cooler. Into the crankcase vent. Back to the engine oil sump. Directly through the exhaust.

From where does the turbocharger receive its oil for lubrication and cooling?. Separate auxiliary oil tank. Gear pump in the exhaust. Engine oil system. Fuel system vapor expansion.

When the wastegate is wide open, is turbocharger speed at its minimum or maximum?. Maximum. Minimum. Modulated. Idle stable.

Does the spring in the wastegate actuator open or close the wastegate valve?. It closes the wastegate, oil pressure opens it. It opens the wastegate, oil pressure closes it. It only controls boost at high power settings. It does neither — electronically controlled.

What happens to turbocharger turbine speed if the wastegate closes?. It decreases. It stays constant. It increases. It oscillates slowly.

What is meant by upper deck pressure?. Pressure inside the carburetor float chamber. Exhaust pressure ahead of the turbine. Discharge pressure of the turbocharger before the throttle valve. Pressure downstream of the cylinders.

Is manifold pressure measured on the engine side of the throttle valve or turbocharger side?. Turbocharger side (before throttle). Engine side (after throttle). Whichever is lower. Fuel servo port.

What is another name for turbocharger discharge pressure?. Carburetor cracked pressure. Bypass pressure. Upper deck pressure. Core pressure.

What is meant by bootstrapping?. When the turbocharger fails to engage. When turbocharger pressure fluctuates with altitude. When turbine speed is controlled solely by engine RPM. When the turbo remains unstable and surges.

What is a turbo-compound system and what kind of turbine does it use?. A system using bleed air turbines to power accessories. A system where exhaust turbines help turn the engine. A turbine that runs separately from exhaust flow. A compressor bypass turbine used only in cruise.

If a technician finds a crack in an exhaust component, how should it be marked?. Lead pencil. Permanent marker. Steel scriber. Wax marker.

What is the purpose of an intercooler on a turbo-supercharged engine?. To heat the air during cold start. To cool the air before it enters the engine. To lubricate the turbo bearings. To maintain constant manifold pressure.

What is the primary purpose of an exhaust augmenter?. o quiet the exhaust. To increase exhaust pressure. To aid in engine cooling. To improve mixture distribution.

Why are aircraft exhaust systems often connected with slip joints and/or ball joints?. To improve torque transfer. To compensate for fuel pressure changes. To prevent noise vibration. To allow flexing due to temperature changes.

What is an effective way of inspecting exhaust systems for cracks?. Ultrasonic testing. X-ray inspection. Dye-penetrant / visual inspection. Tap-hammer method.