FAA Private Pilot Airplane (PAR)Performance, Weight and BalanceEasy
During a preflight inspection, a pilot notes that the aircraft's empty weight has increased since the last weight and balance record. This change is due to the installation of new avionics. How will this increase in empty weight affect the aircraft's useful load?
- AThe useful load will remain unchanged.
- BThe useful load will increase.
- CThe useful load will decrease.
- DThe useful load will only change if the aircraft's maximum takeoff weight is also increased.
Show answer & explanationAnswer & explanation
Correct answer: C. The useful load will decrease.
Useful load is defined as the maximum takeoff weight minus the empty weight. If the empty weight increases and the maximum takeoff weight remains constant, the useful load must decrease.
Why the other options are wrong
- A. Incorrect. Useful load is directly affected by changes in empty weight.
- B. Incorrect. An increase in empty weight, with a constant maximum takeoff weight, will decrease the useful load.
- D. Incorrect. Useful load is a derived value from empty weight and max takeoff weight; an increase in empty weight will decrease it regardless of a max takeoff weight change (unless the max takeoff weight increases by an equal or greater amount, which is not implied here).
Useful Load Definition
Useful load is the weight of the pilot, copilot, passengers, baggage, usable fuel, and drainable oil. It is calculated as the difference between the maximum takeoff weight and the empty weight of the aircraft.
- Useful Load = Max Takeoff Weight - Empty Weight
- Any increase in empty weight reduces useful load
- Any decrease in empty weight increases useful load
Memory trick: Empty Goes Up, Useful Goes Down