FAA Aviation Mechanic Powerplant (AMP)Fuel, Induction and LubricationHard
An aircraft's engine oil consumption rate is measured at 0.8 quarts per hour. If the oil system has a usable capacity of 12 quarts, how many hours of flight can be safely completed before the oil level reaches the minimum safe operating level, assuming a 2-quart reserve is required?
- A10 hours
- B12 hours
- C12.5 hours
- D15 hours
Show answer & explanationAnswer & explanation
Correct answer: C. 12.5 hours
First, calculate the usable oil available: 12 quarts (total) - 2 quarts (reserve) = 10 quarts. Then, divide the usable oil by the consumption rate: 10 quarts / 0.8 quarts/hour = 12.5 hours.
Why the other options are wrong
- A. Incorrect calculation; 10 quarts / 1 hour is 10 hours, but the consumption rate is 0.8 qph.
- B. Incorrect calculation; this would be total capacity divided by 1 qph, or usable capacity divided by 0.8 qph if no reserve was considered.
- D. Incorrect calculation; this would be 12 quarts / 0.8 qph, not accounting for the reserve.
Usable Oil Flight Time Calculation
Determining the maximum safe flight duration based on oil capacity, consumption rate, and required reserve.
- Usable oil = Total capacity - Reserve.
- Flight time = Usable oil / Consumption rate.
- Essential for flight planning and safety.
Memory trick: Total minus reserve, then divide by burn, for hours you've earned.