Loadmaster
From Wikipedia, the free encyclopedia
A loadmaster is an aircrew member on military transport aircraft. Loadmasters serve in the Air Force, Marines, and Navy of many nations. These include the RAF, RAAF, and RNZAF.
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[edit] Duties
The loadmaster performs the calculations and plans cargo and passenger placement to keep the aircraft within permissible center of gravity limits throughout the flight. Loadmasters ensure cargo is placed on the aircraft in such a way as to prevent overloading sensitive sections of the airframe and cargo floor. Considerations are also given to civilian and military regulations which may prohibit the placement of one type of cargo in proximity to another. Unusual cargo may require special equipment to be loaded safely aboard the aircraft, limiting where the other cargo may feasibly be placed.
The loadmaster may physically load the aircraft, but primarily supervises loading crews and procedures. Once positioned aboard the aircraft, the loadmaster ensures it is secured against movement. Chains, straps, and integrated cargo locks are among the most common tools used to secure the cargo. Because the aircraft will execute abrupt maneuvers which may shift the cargo in flight, the loadmaster must determine the appropriate amount and placement of cargo restraint.
Many loadmasters may also be required to be qualified for "aerial delivery" of paratroops or cargo by parachute. Compared to the relatively routine transportation of cargo, airdrops can be a highly technical and dangerous undertaking. Under some situations, the most effective 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.
