Aeronautical Terms beginning with C

Calendar Month

A time period used by the FAA for certification and currency purposes. A calendar month extends from a given day until midnight of the last day of that month.

Civil Air Regulation (CAR)

Predecessor to the Federal Aviation Regulations.

CAMs

The manuals containing the certification rules under the Civil Air Regulations.

Center of Gravity (CG)

(GAMA) The point at which an airplane would balance if suspended. Its distance from the reference datum is determined by dividing the total moment by the total weight of the airplane. It is the mass center of the aircraft, or the theoretical point at which the entire weight of the aircraft is assumed to be concentrated. It may be expressed in percent of MAC (mean aerodynamic cord) or in inches from the reference Center of Lift. The location along the chord line of an airfoil at which all the lift forces produced by the airfoil are considered to be concentrated.

Centroid

The distance in inches aft of the datum of the center of a compartment or a fuel tank for weight and balance purposes.

CG Arm

(GAMA) The arm obtained by adding the airplane’s individual moments and dividing the sum by the total weight.

CG Limits

(GAMA) The extreme center of gravity locations within which the aircraft must be operated at a given weight. These limits are indicated on pertinent FAA aircraft type certificate data sheets, specifications, or weight and balance records.

CG Limits Envelope

An enclosed area on a graph of the airplane loaded weight and the CG location. If lines drawn from the weight and CG cross within this envelope, the airplane is properly loaded.

CG Moment Envelope

An enclosed area on a graph of the airplane loaded weight and loaded moment. If lines drawn from the weight and loaded moment cross within this envelope, the airplane is properly loaded.

Chord

A straight-line distance across a wing from leading edge to trailing edge.

Curtailment

An operator created and FAA-approved operational loading envelope that is more restrictive than the manufacturer’s CG envelope. It ensures that the aircraft will be operated within limits during all phases of flight. Curtailment typically accounts for, but is not limited to, in-flight movement of passengers and crew, service equipment, cargo variation, seating variation, etc.