Configuration of the aircraft:
Consult the aircraft service manual regarding position of the landing gear shock struts and the control surfaces for weighing.
When weighing a helicopter, the main rotor must be in its correct position accordance ATA-8 weight and balance of the specific helicopter.
For the correct cabin and safety items consult the equipment list.
Jacking the aircraft:
Aircarft are often weighed with the use of platform scales (ramp scales).
The aircraft is then rolling them on the platform scales or on to ramps in which load cells are embedded, this eliminates the problems associated with jacking the aicraft of f the ground.
However many aircraft are still weighed by jacking the aircraft up and then lowering them onto scales or load cells.
Extra care must be used when raising an aircraft on jacks for weighing.
For some aircraft stress panels or plates must be installed before the aircraft is raised with wing jacks to distribute the weight over the jack pad.
Be sure to follow the recommendations of the aircraft manufacturer in detail anytime an aircraft is jacked.
As jacks are raised, keep the safety collars screwed down against the jack cylinder to prevent the aircraft from tilting if one of the jacks should lose hydraulic pressure.
Leveling the aircraft:
When an aircraft is weighed, it must be in its level flight attitude so that all of the components are at there correct position and distance from the datum.
Some aircraft rquire a plumb line to be dropped from a specific location so that the point of the weight (the BOB) hangs directly above an identifiable point.
Other aircraft specify that a spirit level to be placed across two leveling lugs, often special srews on the outside of the fuselage.
Other aircraft call for a spirit level to be placed on the upper door sill.
Lateral level is not specified for light all aircraft, but provisions are made on helicopters and multi engine aircraft for determining both longitual and lateral level.
This may be done by build-in leveling indicators, or plumb bob that shows the conditions of both logitudinal and lateral level.
When weighing from the wheels leveling is normally done by adjusting the pressure in the nosewheel shock strut.
Special Safety Considerations:
1.Stress plates must be installed under the jack pad if the manufacturer specifies them.
2.If anyone is rquired to be in the aircraft while it is being jacked, there must be no movement.
3.The jacks must be straight under the jack pads before beginning to raise the aircraft.
4.All jacks must be raised simultaneously and the safety devices are against the jack cylinder to prevent the aircraft from tipping if any jack should lose hydraulic pressure.
Not all jacks have screw collars, some use drop pins or friction locks.