The term ''heavy'' is used during radio transmissions between air traffic control and any aircraft which has been assigned a
maximum takeoff weight
The maximum takeoff weight (MTOW) or maximum gross takeoff weight (MGTOW) or maximum takeoff mass (MTOM) of an aircraft is the maximum weight at which the pilot is allowed to attempt to take off, due to structural or other limits. The analogous ...
(MTOW) rating of or more. Aircraft with a MTOW rating between 7
t and 136 t are considered ''medium'', and aircraft with a MTOW rating less than 7 t are considered ''light''. In the US, the
FAA
The Federal Aviation Administration (FAA) is the largest transportation agency of the U.S. government and regulates all aspects of civil aviation in the country as well as over surrounding international waters. Its powers include air traffic m ...
uses a slightly different categorization, adding a block between medium and heavy, labeling aircraft capable of maximum takeoff weights more than and less than as ''large''.
[FAA Notice N JO 7110.525](_blank)
/ref>
All aircraft produce wingtip vortices that create wake turbulence
Wake turbulence is a disturbance in the atmosphere that forms behind an aircraft as it passes through the air. It includes variety of elements, the most significant of which are wingtip vortices and jetwash. Jetwash refers to the rapidly moving g ...
in flight. The vortex strength increases when the aircraft is heavier and when it flies slowly. Thus, the term "heavy" (unlike light, medium and large) is included by heavy-class aircraft in radio transmissions around airports during take-off and landing, incorporated into the call sign, to warn other aircraft that they should leave additional separation to avoid this wake turbulence. All wide-body aircraft
A wide-body aircraft, also known as a twin-aisle aircraft, is an airliner with a fuselage wide enough to accommodate two passenger aisles with seven or more seats abreast. The typical fuselage diameter is . In the typical wide-body economy cabin ...
are classified as Heavy, with the exception of the first two Airbus A300
The Airbus A300 is a wide-body airliner developed and manufactured by Airbus.
In September 1967, aircraft manufacturers in the United Kingdom, France, and West Germany signed a memorandum of understanding to develop a large airliner.
West G ...
s produced (the A300B1, MTOW of only , both shorter and lighter than the mass-production A300s), while the Airbus A380
The Airbus A380 is a large wide-body airliner that was developed and produced by Airbus. It is the world's largest passenger airliner and only full-length double-deck jet airliner.
Airbus studies started in 1988, and the project was annou ...
(MTOW of ) and the single Antonov An-225
The Antonov An-225 Mriya ( uk, Антонов Ан-225 Мрія, lit=dream' or 'inspiration; NATO reporting name: Cossack) was a strategic airlift cargo aircraft designed and produced by the Antonov Design Bureau in the Soviet Union.
It was ...
, before its destruction, (MTOW of ) are classified in the even larger category of ''super''. Certain variants of the narrow-bodied Boeing 707
The Boeing 707 is an American, long-range, narrow-body airliner, the first jetliner developed and produced by Boeing Commercial Airplanes.
Developed from the Boeing 367-80 prototype first flown in 1954, the initial first flew on December 20, ...
and Douglas DC-8
The Douglas DC-8 (sometimes McDonnell Douglas DC-8) is a long-range narrow-body airliner built by the American Douglas Aircraft Company.
After losing the May 1954 US Air Force tanker competition to the Boeing KC-135, Douglas announced in Ju ...
were considered "heavy" based on MTOW.
Of special note here is the narrow-bodied Boeing 757
The Boeing 757 is an American narrow-body airliner designed and built by Boeing Commercial Airplanes.
The then-named 7N7, a twinjet successor for the 727 (a trijet), received its first orders in August 1978.
The prototype completed its mai ...
. Under current guidance, the 757 is considered not to be large, having a MTOW of only . However, after a number of accidents where smaller aircraft following closely behind a 757 crashed, the rules were changed so that controllers are required to apply the special wake turbulence separation criteria specified in paragraph 5-5-4 in the FAA guidelines for aircraft separation, as though the 757 were heavy.
References
{{reflist
External links
FAA Order 7110.65Z Air Traffic Control
FAA Order 7360.1E Aircraft Type Designators
Air traffic control
Call signs