FAA Instrument Rating Airplane (IRA)Regulations and CurrencyMedium
A pilot planning an IFR flight computes a cruise fuel burn of 10 gallons per hour and determines that no alternate airport is required. Per 14 CFR 91.167, what is the minimum fuel that must remain after arriving over the first airport of intended landing?
- A5.0 gallons
- B10.0 gallons
- C7.5 gallons
- D15.0 gallons
Show answer & explanationAnswer & explanation
Correct answer: C. 7.5 gallons
14 CFR 91.167 requires enough fuel to fly to the first airport of intended landing and then fly for 45 minutes at normal cruising speed. At 10 gallons per hour, 45 minutes (0.75 hour) of fuel equals 10 × 0.75 = 7.5 gallons.
Why the other options are wrong
- A. 5.0 gallons corresponds to only 30 minutes of reserve, not 45.
- B. 10.0 gallons would represent a full hour of reserve, more than required.
- D. 15.0 gallons represents 1.5 hours, far exceeding the regulatory minimum.
IFR Fuel Reserve (91.167)
IFR flights must carry enough fuel to reach the destination, then the alternate (if required), plus fly 45 minutes at normal cruising speed.
- 45-minute reserve after destination/alternate
- VFR reserve is only 30 minutes (91.151) — different rule
- Reserve calculated at normal cruising speed fuel burn
Memory trick: 'IFR: 45 minutes more.'