Loadmaster

From Wikipedia, the free encyclopedia

A loadmaster is an aircrew member on military transports. Loadmasters serve in the Air Force, Marines, and Navy. A loadmaster's duties are mentally demanding and can be physically stressful. The ranks of loadmasters include both men and women.

1 Duties
2 History
3 References
4 See also

[edit] Duties

The loadmaster also performs the calculations and plans load and passenger placement to keep the aircraft within permissible "CG limits" throughout the flight. This is not simply a matter of putting the cargo on and running the aircraft across a scale. There are no scales used for this purpose. Further, there are design limits regarding how much weight the airframe will withstand in a particular compartment, as well as floor limits regarding the pounds per square inch the floor will tolerate. Additionally, there are regulations which may prohibit the placement of one type of cargo near another. Furthermore, unusual cargo may require special equipment to place it aboard, and this may limit where the other cargo may feasibly be placed. The loadmaster must take all of these factors into account when planning load placement aboard the aircraft.

The loadmaster does not physically load the aircraft, but does supervise loading crews and operate loading equipment which is integral to the aircraft. Once the cargo is positioned aboard the aircraft, it must be secured against movement. Because the aircraft will execute maneuvers which exert forces which are multiples of the force of gravity (so-called "G forces"), the loadmaster must determine the appropriate amount of restraint to employ on certain types of cargo, and direct the loading crews in the proper placement of these restraints.

Loadmasters are also required to be qualified for "aerial delivery" of paratroops or cargo by parachute. This is a highly technical and dangerous undertaking. Sometimes, particularly in siege situations, the only way to resupply ground troops is by aerial delivery of equipment, ammunition, food and medical supplies. Many military victories have been dependent in large part upon aerial delivery.

[edit] History

During World War II, many transport aircraft crashed because of improper weight and balance. The calculation of weight and balance became more important as aircraft grew larger and the missions became longer. Eventually personnel were trained to perform calculation of weight and balance and became part of the military aircrew on transport planes. Such crew persons were called by various titles. The term "loadmaster" is believed to have been created by the Douglas Aircraft Company, because the first known use of the term appears in the flight manuals for the C-124 Globemaster II aircraft, the largest piston-engine transport aircraft in the US inventory at the time.

A fixed-wing aircraft is supported in flight only by its wing(s). For an aircraft to become and remain airborne, the wing must move through the air at a specified "angle of attack". To assure that the wing moves through the air at the proper angle of attack, the aircraft's center of gravity must fall within a range specified by the aircraft's designers. An aircraft which is too nose-heavy or too tail-heavy will not fly properly, because the angle of attack is affected adversely. This can destroy lift, and cause a stall in certain maneuvers. A stall can cause a plane to fail to fly.

The center of gravity of a transport aircraft is a function of a number of factors: the weight of the empty aircraft (the so-called "basic weight"), the weight of the fuel load (usually carried only in the wings), the weight of the cargo and passengers, and the weight of the crew, and the positions of each of these factors. The weight of each of these factors is known before a flight. What varies from flight to flight is not only the weight of any or all of these factors, but the position of such factors as fuel, passengers and cargo. The weight of each of these factors is converted into a "moment", by multiplying the weight of each item times its distance from a reference point which was established when the aircraft was designed. The sum of all moments is then divided by the sum of all weights and the result is the "center of gravity" for the aircraft with crew, fuel, cargo and passengers aboard. This center of gravity must be within a range specified by the designers. Furthermore, as fuel is burned off during flight the center of gravity changes continually, so that the aircraft becomes either more nose-heavy or more tail-heavy as the flight continues. This must be taken into account when the aircraft is loaded. An aircraft which was "within limits" on takeoff could, in the course of a flight, become "out of limits" because of fuel burnoff.