Which condition may cause erroneous readings when weighing under the wings or under the landing gear wheels?

Which condition may cause erroneous readings when weighing under the wings or under the landing gear wheels?

• A. Gear downlocks installed
• B. Parking brakes not set
• C. Wheel chocks removed
• D. Parking brakes set

Answer: (D)

When weighing an aircraft, you want the scale readings to reflect only the aircraft’s weight. If the parking brakes are set, the wheel brakes apply friction to the wheels, and that braking force is transmitted through the landing gear into the aircraft’s structure. That additional drag changes the load the scales read, giving an erroneous weight measurement. Releasing the parking brakes removes that extra load, allowing a true reading. The other conditions don’t introduce this braking load in the weighing setup.

When weighing an aircraft, you want the scale readings to reflect only the aircraft’s weight. If the parking brakes are set, the wheel brakes apply friction to the wheels, and that braking force is transmitted through the landing gear into the aircraft’s structure. That additional drag changes the load the scales read, giving an erroneous weight measurement. Releasing the parking brakes removes that extra load, allowing a true reading. The other conditions don’t introduce this braking load in the weighing setup.