FAA Engine Fuel and Fuel Metering Systems (3)

When a new carburetor is installed on an engine. Warm up the engine and adjust the float level. do not adjust the idle mixture setting; this was accomplished on the flow bench. and the engine is warmed up to normal temperatures, adjust the idle mixture, then the idle speed.

For what primary purpose is a turbine engine fuel control unit trimmed?. To obtain maximum thrust output when desired. To properly position the power levers. To adjust the idle RPM.

What factor is not used in the operation of an aircraft gas turbine engine fuel control unit?. Compressor inlet air temperature. Mixture control position. Power lever position.

Where is the throttle valve located on a float-type carburetor?. Between the venturi and the discharge nozzle. After the main discharge nozzle and venturi. After the venturi and just before the main discharge nozzle.

One purpose of an air bleed in a float-type carburetor is to. increase fuel flow at altitude. meter air to adjust the mixture. decrease fuel density and destroy surface tension.

The purpose of the diaphragm in most vane-type fuel pumps is to. maintain fuel pressure below atmospheric pressure. equalize fuel pressure at all speeds. compensate fuel pressures to altitude changes.

What component is used to ensure fuel delivery during periods of rapid engine acceleration?. Acceleration pump. Engine-driven fuel pump. Power enrichment unit.

It is necessary to control acceleration and deceleration rates in turbine engines in order to. prevent blowout or die-out. prevent overtemperature. prevent friction between turbine wheels and the case due to expansion and contraction.

Reciprocating engine power will be decreased at all altitudes if the. air density is increased. humidity is increased. manifold pressure is increased.

When troubleshooting an engine that will not idle, what would be a probable cause?. Economizer valve not operating correctly. Mixture setting too rich. Manifold valve is not operating properly.

Which of the following is NOT an input parameter for a turbine engine fuel control unit?. Compressor inlet pressure. Compressor inlet temperature. Ambient humidity.

What should be checked/changed to ensure the validity of a turbine engine performance check if an alternate fuel is to be used?. Fuel specific gravity setting. Maximum RPM adjustment. EPR gauge calibration.

Prior to performing engine trimming, the aviation mechanic should. call the control tower to obtain current sea level barometric pressure and temperature. observe the reading on the aircraft outside air temperature (OAT) gauge. obtain a true temperature reading comparable to that of the air that enters the engine.

The desired engine idle speed and mixture setting. is adjusted with engine warmed up and operating. should give minimum RPM with maximum manifold pressure. is usually adjusted in the following sequence; speed first, then mixture.

Which of the following best describes the function of an altitude mixture control?. Regulates the richness of the fuel/air charge entering the engine. Regulates the air pressure above the fuel in the float chamber. Regulates the air pressure in the venturi.

Which of the following best describes the function of an automatic mixture control (AMC)?. It compensates for change in the air density due to temperature and altitude. It compensates for the air pressure above the fuel in the float chamber. It compensates for the air pressure in the venturi of a float-type carburetor.

The active clearance control (ACC) portion of an EEC system aids turbine engine efficiency by. adjusting stator vane position according to operating conditions and power requirements. ensuring turbine blade to engine case clearances are kept to a minimum by controlling case temperatures. automatically adjusting engine speed to maintain a desired EPR.

An aircraft carburetor is equipped with a mixture control in order to prevent the mixture from becoming too. lean at high altitudes. rich at high altitudes. rich at high speeds.

When air passes through the venturi of a carburetor, what three changes occur?. Velocity increases, temperature increases, and pressure decreases. Velocity decreases, temperature increases, and pressure increases. Velocity increases, temperature decreases, and pressure decreases.

Float-type carburetors which are equipped with economizers are normally set for. their richest mixture delivery and leaned by means of the economizer system. the economizer system to supplement the main system supply at all engine speeds above idling. their leanest practical mixture delivery at cruising speeds and enriched by means of the economizer system at higher power settings.

(Refer to Figure 6.) Which curve most nearly represents an aircraft engine's air-fuel ratio throughout its operating range?. 1. 3. 2.

A carburetor is prevented from leaning out during quick acceleration by the. power enrichment system. mixture control system. accelerating system.

When checking the idle mixture on a carburetor, the engine should be idling normally, then pull the mixture control toward the IDLE CUTOFF position. A correct idling mixture will be indicated by. an immediate decrease in RPM. a decrease of 20 to 30 RPM before quitting. an increase of 10 to 50 RPM before decreasing.

Detonation occurs when the air-fuel mixture. burns too fast. ignites before the time of normal ignition. is too rich.

What is the relationship between the pressure existing within the throat of a venturi and the velocity of the air passing through the venturi?. There is no direct relationship between the pressure and the velocity. The pressure is directly proportional to the velocity. The pressure is inversely proportional to the velocity.

What is the purpose of an engine-driven fuel pump bypass valve?. To divert the excess fuel back to the main tank. To prevent a damaged or inoperative pump from blocking the fuel flow of another pump in series with it. To divert the excess fuel from the pressure side of the pump to the inlet side of the pump.

What is the possible cause of an engine running rich at full throttle if it is equipped with a float-type carburetor?. Float level too low. Clogged main air bleed. Clogged atmospheric vent.

On a carburetor without an automatic mixture control as the aircraft ascends to altitude, the mixture will. be enriched. be leaned. not be affected.

The purpose of the back-suction mixture control in a float-type carburetor is to adjust the mixture by. regulating the pressure drop at the venturi. regulating the pressure on the fuel in the float chamber. regulating the suction on the mixture from behind the throttle valve.

Generally, the practice when trimming an engine is to. turn all accessory bleed air off. turn all accessory bleed air on. make adjustments (as necessary) for all engines on the same aircraft with accessory bleed air settings the same -- either on or off.