Aeronautical Terms beginning with D

Datum

An imaginary vertical plane or line from which all measurements of arms are taken. The datum is established by the manufacturer. Once the datum has been selected, all moment arms and the location of CG range are measured from this point.

Delta ∆

This symbol, ∆, means a change in something. ∆CG means a change in the center of gravity location.

Dynamic Load

The actual weight of the aircraft multiplied by the load factor, or the increase in weight caused by acceleration.