SPC Aircraft Systems and Performance 2 — Questions and Answers
Question 1: What is the purpose of the aircraft's primer system?
- To inject fuel directly into the cylinders for easier cold-weather starting (Correct answer)
- To pressurize the fuel tanks before engine start
- To lubricate the engine cylinders before startup
- To pre-heat the carburetor to prevent icing
Correct answer: To inject fuel directly into the cylinders for easier cold-weather starting
The primer pumps fuel directly into the cylinders or intake manifold to enrich the mixture for cold engine starting.
Question 2: At what altitude does a normally aspirated engine lose approximately 3% of its power for every 1,000 feet gained?
- Above 5,000 feet MSL only
- From sea level upward (Correct answer)
- Only above the critical altitude
- Above 10,000 feet MSL only
Correct answer: From sea level upward
A normally aspirated engine loses roughly 3% of its rated power for each 1,000 feet of altitude gain starting from sea level.
Question 3: What does the VSO airspeed indicate on the airspeed indicator?
- Stalling speed in the landing configuration (Correct answer)
- Maximum structural cruising speed
- Stalling speed in the clean configuration
- Never-exceed speed
Correct answer: Stalling speed in the landing configuration
VSO is the stalling speed or minimum steady flight speed in the landing configuration (gear down, flaps fully extended).
Question 4: Which fuel system component prevents vapor lock by maintaining positive fuel pressure to the carburetor?
- Electric boost pump (Correct answer)
- Primer
- Fuel strainer
- Mixture control
Correct answer: Electric boost pump
An electric boost pump maintains fuel pressure and helps prevent vapor lock, especially during hot-weather operations.
Question 5: What happens to density altitude on a hot, humid day at a given field elevation?
- Density altitude increases above field elevation (Correct answer)
- Density altitude equals field elevation regardless of conditions
- Density altitude decreases below field elevation
- Humidity has no effect on density altitude
Correct answer: Density altitude increases above field elevation
High temperature and high humidity both reduce air density, causing density altitude to rise above the actual field elevation.
Question 6: What is the function of the aircraft's magneto?
- To generate high-voltage electrical sparks to ignite the fuel-air mixture (Correct answer)
- To charge the aircraft battery during cruise flight
- To power the aircraft's avionics systems
- To regulate voltage to the instrument panel
Correct answer: To generate high-voltage electrical sparks to ignite the fuel-air mixture
Magnetos are self-contained ignition generators that produce high-voltage electricity to fire the spark plugs, independent of the aircraft battery.
Question 7: What is the effect of lowering flaps on an aircraft's stall speed?
- Stall speed decreases because flaps increase lift at lower airspeeds (Correct answer)
- Stall speed increases because flaps add drag
- Stall speed remains unchanged regardless of flap position
- Stall speed increases because the wing area is enlarged
Correct answer: Stall speed decreases because flaps increase lift at lower airspeeds
Lowering flaps increases lift coefficient, allowing the wing to generate sufficient lift at a lower airspeed, thus reducing stall speed.
SPC Aircraft Systems and Performance 2
What is the purpose of the aircraft's primer system?