Aircraft Systems QZ1 Flashcards
With regard to carburetor ice, float-type carburetor systems in comparison to fuel injection systems are generally considered to be
1. Equally susceptible to icing.
2. More susceptible to icing.
3. Less susceptible to icing.
- More susceptible to icing.
Explanation: One disadvantage of the float-type carburetor is its icing tendency. Carburetor ice occurs due to the effect of fuel vaporization and the decrease in air pressure in the venturi, which causes a sharp temperature drop in the carburetor. If water vapor in the air condenses when the carburetor temperature is at or below freezing, ice may form on internal surfaces of the carburetor, including the throttle valve.
What should be the first action after starting an aircraft engine?
1. Test each brake and the parking brake.
2. Place the magneto or ignition switch momentarily in the OFF position to check for proper grounding.
3. Adjust for proper RPM and check for desired indications on the engine gauges.
- Adjust for proper RPM and check for desired indications on the engine gauges.
After starting the engine, adjust for the proper RPM (usually 800-1,000 RPM) and check the gauges to ensure oil pressure is positive. If there is no oil pressure, shut the engine down immediately to prevent damage to the engine and have the engine checked by a qualified A&P.
Which would most likely cause the cylinder head temperature and engine oil temperature gauges to exceed their normal operating ranges?
1. Using fuel that has a lower-than-specified fuel rating.
2. Using fuel that has a higher-than-specified fuel rating.
3. Operating with higher-than-normal oil pressure.
- Using fuel that has a lower-than-specified fuel rating.
Explanation: A lower octane rating increases cylinder head temperature because it causes the fuel to burn faster and more completely, raising combustion temperatures. This higher heat can lead to increased thermal stress on engine components. To fix this, you can use a fuel with the appropriate octane rating specified by the engine manufacturer, which ensures proper combustion timing and temperature control. Additionally, maintaining the engine’s cooling system, using proper spark plugs, and ensuring the fuel mixture is correct can help manage cylinder head temperatures.
Which condition is most favorable to the development of carburetor icing?
1. Temperature between 20°F and 70°F and high humidity.
2. Any temperature below freezing and a relative humidity of less than 50 percent.
3. Temperature between 32°F and 50°F and low humidity.
- Temperature between 20°F and 70°F and high humidity.
Explanation: Carburetor ice is most likely to occur when temperatures are below 70 degrees Fahrenheit (°F) or 21 degrees Celsius (°C) and the relative humidity is above 80 percent. Due to the sudden cooling that takes place in the carburetor, icing can occur even in outside air temperatures as high as 100 °F (38 °C) and humidity as low as 50 percent.
On aircraft equipped with fuel pumps, when is the auxiliary electric driven pump used?
1. In the event engine-driven fuel pump fails.
2. All the time to aid the engine-driven fuel pump.
3. Constantly except in starting the engine.
- In the event engine-driven fuel pump fails.
Explanation: Aircraft with fuel-pump systems have two fuel pumps. The main pump system is engine driven with an electrically- driven auxiliary pump provided for use in engine starting and in the event the engine pump fails. The auxiliary pump, also known as a boost pump, provides added reliability to the fuel system. The electrically-driven auxiliary pump is controlled by a switch in the flight deck.
