FAA Flight Instructor Airplane (FIA)Performance, Weight and BalanceMedium
An airplane departs with a takeoff weight of 3,380 lb. The POH lists a maximum landing weight of 3,200 lb. The airplane burns fuel at 10 gallons per hour, and each gallon of fuel weighs 6 lb. Assuming no other weight changes occur, approximately how long must the flight continue before the airplane's weight is reduced to the maximum landing weight?
- A18 hours
- B3.0 hours
- C5.0 hours
- D1.8 hours
Show answer & explanationAnswer & explanation
Correct answer: B. 3.0 hours
Excess weight = 3,380 − 3,200 = 180 lb. Fuel to burn = 180 lb ÷ 6 lb/gal = 30 gal. Time = 30 gal ÷ 10 gal/hr = 3.0 hours.
Why the other options are wrong
- A. Fails to divide by the fuel flow rate, using gallons as hours directly.
- C. Uses an incorrect excess weight of 300 lb.
- D. Divides excess weight directly by fuel flow rate without converting to gallons.
Maximum Landing Weight
Some airplanes have a maximum landing weight lower than maximum takeoff weight; pilots may need to burn fuel before landing to comply.
- Excess weight (lb) ÷ fuel weight per gallon = gallons to burn
- Gallons to burn ÷ fuel flow rate = time required
- Applies mainly to larger/turbine aircraft, but tested conceptually for all pilots
Memory trick: Burn it down before you touch the ground.