When an aircraft is positioned for weighing on scales located under each landing gear wheel, which of the following may cause erroneous scale readings?

When an aircraft is positioned for weighing on scales located under each landing gear wheel, which of the following may cause erroneous scale readings?

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

Answer: (D)

When you weigh the aircraft on scales under each wheel, each scale is measuring the vertical load that gear bears. If the parking brakes are set, the braking system applies torque to the wheel hub and transmits through the landing gear structure. That brake-induced force becomes part of what the scale must support, distorting the true vertical weight reading. In other words, the brake torque adds or shifts load in a way that doesn’t reflect gravity alone, leading to erroneous readings. To get accurate results, the brakes should be released so no brake torque affects the gear during weighing. The other conditions don’t introduce that braking force and thus don’t distort the readings to the same extent.

When you weigh the aircraft on scales under each wheel, each scale is measuring the vertical load that gear bears. If the parking brakes are set, the braking system applies torque to the wheel hub and transmits through the landing gear structure. That brake-induced force becomes part of what the scale must support, distorting the true vertical weight reading. In other words, the brake torque adds or shifts load in a way that doesn’t reflect gravity alone, leading to erroneous readings. To get accurate results, the brakes should be released so no brake torque affects the gear during weighing. The other conditions don’t introduce that braking force and thus don’t distort the readings to the same extent.