Equipment for Weighing
There are two basic types of scales used to weigh aircraft: scales on which the aircraft is rolled
so that the weight is taken at the wheels, and electronic load cells type where a pressure
sensitive cell are placed between the aircraft jack and the jack pads on the aircraft.
Some aircraft are weighed with mechanical scales of the low-profile type similar to those shown in
Figure 3-1.
Large aircraft, including heavy transports, are weighed
by rolling them onto weighing platforms with electronic weighing cells that accurately measure the
force applied by the weight of the aircraft.
Electronic load cells are used when the aircraft is weighed by raising it on jacks. The cells are
placed between the jack and the jack pad on the aircraft, and the aircraft is raised on the jacks
until the wheels or skids are off the floor and the aircraft is in a level flight attitude. The
weight measured by each load cell is indicated on the control panel. [Figure 3-27]
Mechanical scales should be protected when they are not in use, and they must be periodically
checked for accuracy by measuring a known weight. Electronic scales normally have a built-in
calibration that allows them to be accurately zeroed before any load is applied.