Aircraft Weighing

Aircraft must be weighed before entering service, to determine the individual mass and CG position. This should be done once all manufacturing processes have been completed. The aircraft must also be re-weighed within four years from the date of manufacture, if individual mass is used, or within nine years from the date of manufacture, if fleet masses are used.

The mass and CG position of an aircraft must be periodically re-established. The maximum interval between one aircraft weigh and the next, must be defined by the operator, but not exceed the four/nine year limits.

In addition the mass and CG position should be re-established either by weighing or calculation when the cumulative changes in the:

·         Dry Operating Mass exceed ± 0.5%

·         CG position exceeds ± 0.5% of the MAC.

An aircraft may be transferred from one JAA operator to another without re-weighing provided both have an approved mass control programme.

Individual or Fleet Mass

When an operator has a number of aircraft of the same type and configuration, he may wish to use the average Dry Operating Mass and CG position of this group of aircraft. The use of fleet mass and CG position is controlled by strict rules to ensure that all aircraft in the fleet stay within the specified limits. If one aircraft exceeds these specified limits, it must be removed from the fleet calculations and individual mass restrictions will apply.