Fuel dumping
Encyclopedia
Aircraft
An aircraft is a vehicle that is able to fly by gaining support from the air, or, in general, the atmosphere of a planet. An aircraft counters the force of gravity by using either static lift or by using the dynamic lift of an airfoil, or in a few cases the downward thrust from jet engines.Although...
in certain emergency situations before a return to the airport shortly after takeoff, or before landing short of its intended destination (emergency landing
Emergency landing
An emergency landing is a landing made by an aircraft in response to a crisis which either interferes with the operation of the aircraft or involves sudden medical emergencies necessitating diversion to the nearest airport.-Types of emergency landings:...
) to lighten the aircraft's weight
Aircraft gross weight
The aircraft gross weight is the total aircraft weight at any moment during the flight or ground operation.The aircraft gross weight decreases during flight due to fuel and oil consumption...
.
Aircraft fuel dump
Aircraft have two major types of weight limits: the maximum takeoff weight and the maximum structural landing weightMaximum Landing Weight
The Maximum Landing Weight is the maximum aircraft gross weight due to design or operational limitations at which an aircraft is permitted to land...
, with the maximum structural landing weight always being the lower of the two. This allows an aircraft on a normal, routine flight
Flight
Flight is the process by which an object moves either through an atmosphere or beyond it by generating lift or propulsive thrust, or aerostatically using buoyancy, or by simple ballistic movement....
to take off at the higher weight, consume fuel en route, and arrive at a lower weight. There are other variables involving takeoff and landing weights, but they are omitted from this article for the sake of simplicity.
It is the abnormal, non-routine flight where landing weight can be an issue. If a flight takes off at the maximum structural takeoff weight and then faces a situation where it must return to the departure airport (due to certain mechanical problems, or a passenger medical issue), there will not be time to consume the fuel meant for getting to the original destination, and the aircraft may be over the maximum structural landing weight to land back at the departure point.
As jets began flying with U.S. airlines in the late 1950s and early 1960s, the FAA
Federal Aviation Administration
The Federal Aviation Administration is the national aviation authority of the United States. An agency of the United States Department of Transportation, it has authority to regulate and oversee all aspects of civil aviation in the U.S...
rule in effect at the time mandated that if the ratio between an aircraft's maximum structural takeoff weight and its maximum structural landing weight was greater than 105%, the aircraft had to have a fuel dump system installed. Accordingly, aircraft such as the Boeing 707
Boeing 707
The Boeing 707 is a four-engine narrow-body commercial passenger jet airliner developed by Boeing in the early 1950s. Its name is most commonly pronounced as "Seven Oh Seven". The first airline to operate the 707 was Pan American World Airways, inaugurating the type's first commercial flight on...
and 727
Boeing 727
The Boeing 727 is a mid-size, narrow-body, three-engine, T-tailed commercial jet airliner, manufactured by Boeing. The Boeing 727 first flew in 1963, and for over a decade more were built per year than any other jet airliner. When production ended in 1984 a total of 1,832 aircraft had been produced...
and the Douglas DC-8
Douglas DC-8
The Douglas DC-8 is a four-engined narrow-body passenger commercial jet airliner, manufactured from 1958 to 1972 by the Douglas Aircraft Company...
had fuel dump systems. Any of those aircraft needing to return to a takeoff airport above the maximum structural landing weight would simply jettison an amount of fuel sufficient to reduce the aircraft's total weight to below that maximum structural landing weight limit, and then land.
During the 1960s, Boeing
Boeing
The Boeing Company is an American multinational aerospace and defense corporation, founded in 1916 by William E. Boeing in Seattle, Washington. Boeing has expanded over the years, merging with McDonnell Douglas in 1997. Boeing Corporate headquarters has been in Chicago, Illinois since 2001...
introduced the 737
Boeing 737
The Boeing 737 is a short- to medium-range, twin-engine narrow-body jet airliner. Originally developed as a shorter, lower-cost twin-engine airliner derived from Boeing's 707 and 727, the 737 has developed into a family of nine passenger models with a capacity of 85 to 215 passengers...
, and Douglas
Douglas Aircraft Company
The Douglas Aircraft Company was an American aerospace manufacturer, based in Long Beach, California. It was founded in 1921 by Donald Wills Douglas, Sr. and later merged with McDonnell Aircraft in 1967 to form McDonnell Douglas...
the DC-9
McDonnell Douglas DC-9
The McDonnell Douglas DC-9 is a twin-engine, single-aisle jet airliner. It was first manufactured in 1965 with its maiden flight later that year. The DC-9 was designed for frequent, short flights. The final DC-9 was delivered in October 1982.The DC-9 was followed in subsequent modified forms by...
, the original models of each being for shorter routes; the 105% figure was not an issue, thus they had no fuel dump systems installed. During the 1960s and 1970s, both Boeing and Douglas "grew" their respective aircraft as far as operational capabilities were concerned via Pratt & Whitney
Pratt & Whitney
Pratt & Whitney is a U.S.-based aerospace manufacturer with global service operations. It is a subsidiary of United Technologies Corporation . Pratt & Whitney's aircraft engines are widely used in both civil aviation and military aviation. Its headquarters are in East Hartford, Connecticut, USA...
's development of increasingly powerful variants of the JT8D engines that powered both aircraft series. Both aircraft were now capable of longer duration flights, with increased weight limits, and complying with the existing 105% rule became problematic due to the costs associated with adding a fuel dump system to aircraft in production. Considering the more powerful engines that had been developed, the FAA changed the rules to delete the 105% requirement, and FAR 25.1001 was enacted stating a jettison system was not required if the climb requirements of FAR 25.119 (Landing Climb) and FAR 25.121 (Approach Climb) could be met, assuming a 15-minute flight. In other words, for a go-around with full landing flaps
Flap (aircraft)
Flaps are normally hinged surfaces mounted on the trailing edges of the wings of a fixed-wing aircraft to reduce the speed an aircraft can be safely flown at and to increase the angle of descent for landing without increasing air speed. They shorten takeoff and landing distances as well as...
and all engines operating, and at approach flap setting and one engine inoperative, respectively.
Since most twinjet airliners can meet these requirements, most aircraft of this type such as the Boeing 737
Boeing 737
The Boeing 737 is a short- to medium-range, twin-engine narrow-body jet airliner. Originally developed as a shorter, lower-cost twin-engine airliner derived from Boeing's 707 and 727, the 737 has developed into a family of nine passenger models with a capacity of 85 to 215 passengers...
(all models), the DC-9/MD80 and Boeing 717
Boeing 717
The Boeing 717 is a twin-engine, single-aisle jet airliner, developed for the 100-seat market. The airliner was designed and marketed by McDonnell Douglas as the MD-95, a third-generation derivative of the DC-9. Capable of seating of up to 117 passengers, the 717 has maximum range of...
, the A320 family
Airbus A320 family
The Airbus A320 family is a family of short- to medium-range, narrow-body, commercial passenger jet airliners manufactured by Airbus Industrie.Airbus was originally a consortium of European aerospace companies, and is now fully owned by EADS. Airbus's name has been Airbus SAS since 2001...
and various regional jet ("RJ
Regional jet
A Regional jet , is a class of short to medium-range turbofan powered airliners.-History:The term "Regional jet" describes a range of short to medium-haul turbofan powered aircraft, whose use throughout the world expanded after the advent of Airline Deregulation in the United States in...
") aircraft do not have fuel dump systems installed. In the event of an emergency requiring a return to the departure airport, the aircraft circles nearby in order to consume fuel to get down to within the maximum structural landing weight limit, or if the situation demands it, simply lands overweight without delay. Modern aircraft are designed with possible overweight landings in mind, but this is not done except in cases of emergency, and various maintenance
Aircraft maintenance
Aircraft maintenance is the overhaul, repair, inspection or modification of an aircraft or aircraft component.Maintenance includes the installation or removal of a component from an aircraft or aircraft subassembly, but does not include:...
inspections are required afterwards.
Many movies and TV news stories mistakenly assume that all aircraft can dump fuel, when in fact most cannot. In certain atmospheric conditions where the moisture content of the air is high, 737s
Boeing 737
The Boeing 737 is a short- to medium-range, twin-engine narrow-body jet airliner. Originally developed as a shorter, lower-cost twin-engine airliner derived from Boeing's 707 and 727, the 737 has developed into a family of nine passenger models with a capacity of 85 to 215 passengers...
(and other aircraft) flying at low altitudes sometimes leave a moisture trail
Contrail
Contrails or vapour trails are artificial clouds that are the visible trails of condensed water vapour made by the exhaust of aircraft engines...
that can come off the top of the wing, wingtips, or trailing edge flaps. Moisture trails coming off the trailing edge flaps can appear especially odd, since the moisture is being "spun" by aerodynamic forces. It is possible that some people observe these moisture trails and wrongly think fuel is being dumped.
Longer-range twin jets such as the Boeing 767
Boeing 767
The Boeing 767 is a mid-size, wide-body twin-engine jet airliner built by Boeing Commercial Airplanes. It was the manufacturer's first wide-body twinjet and its first airliner with a two-crew glass cockpit. The aircraft features two turbofan engines, a supercritical wing, and a conventional tail...
and the Airbus A300
Airbus A300
The Airbus A300 is a short- to medium-range widebody jet airliner. Launched in 1972 as the world's first twin-engined widebody, it was the first product of Airbus Industrie, a consortium of European aerospace companies, wholly owned today by EADS...
, A310
Airbus A310
The Airbus A310 is a medium- to long-range twin-engine widebody jet airliner. Launched in July 1978, it was the second aircraft created by Airbus Industrie,a consortium of European aerospace companies, Airbus is now fully owned by EADS and since 2001 has been known as Airbus SAS. the consortium of...
, and A330
Airbus A330
The Airbus A330 is a wide-body twin-engine jet airliner made by Airbus, a division of EADS. Versions of the A330 have a range of and can accommodate up to 335 passengers in a two-class layout or carry of cargo....
may or may not have fuel dump systems, depending upon how the aircraft was ordered, since on some aircraft they are a customer option. Three- and four-engine jets like the Lockheed L-1011
Lockheed L-1011
The Lockheed L-1011 TriStar, commonly referred to as the L-1011 or TriStar, is a medium-to-long range, widebody passenger trijet airliner. It was the third widebody airliner to enter commercial operations, following the Boeing 747 and the McDonnell Douglas DC-10. Between 1968 and 1984, Lockheed...
, McDonnell Douglas DC-10
McDonnell Douglas DC-10
The McDonnell Douglas DC-10 is a three-engine widebody jet airliner manufactured by McDonnell Douglas. The DC-10 has range for medium- to long-haul flights, capable of carrying a maximum 380 passengers. Its most distinguishing feature is the two turbofan engines mounted on underwing pylons and a...
/ MD-11, Boeing 747
Boeing 747
The Boeing 747 is a wide-body commercial airliner and cargo transport, often referred to by its original nickname, Jumbo Jet, or Queen of the Skies. It is among the world's most recognizable aircraft, and was the first wide-body ever produced...
and Airbus A340
Airbus A340
The Airbus A340 is a long-range four-engine wide-body commercial passenger jet airliner. Developed by Airbus Industrie,A consortium of European aerospace companies, Airbus is now fully owned by EADS and since 2001 has been known as Airbus SAS. a consortium of European aerospace companies, which is...
usually have difficulty meeting the requirements of FAR 25.119 near maximum structural takeoff weight, so most of those have jettison systems. A Boeing 757
Boeing 757
The Boeing 757 is a mid-size, narrow-body twin-engine jet airliner manufactured by Boeing Commercial Airplanes. Passenger versions of the twinjet have a capacity of 186 to 289 persons and a maximum range of , depending on variant and cabin configuration...
has no fuel dump capability as its maximum landing weight is similar to the maximum take-off weight.
Fuel dumping operations are coordinated with air traffic control
Air traffic control
Air traffic control is a service provided by ground-based controllers who direct aircraft on the ground and in the air. The primary purpose of ATC systems worldwide is to separate aircraft to prevent collisions, to organize and expedite the flow of traffic, and to provide information and other...
, and precautions are taken to keep other aircraft clear of such areas. Fuel dumping is usually accomplished at a high enough altitude where the fuel will dissipate before reaching the ground. Fuel leaves the aircraft through a specific point on each wing, usually closer to the wingtips and further away from engines, and initially appears as more liquid than vapor.
The largest scale fuel dumping occurred on September 11, 2001, when many international flights were refused American airspace entry due to numerous hijacking
Aircraft hijacking
Aircraft hijacking is the unlawful seizure of an aircraft by an individual or a group. In most cases, the pilot is forced to fly according to the orders of the hijackers. Occasionally, however, the hijackers have flown the aircraft themselves, such as the September 11 attacks of 2001...
incidents. Many of these international flights were fueled for travel well into the American interior. Many such flights were diverted into Canadian
Canada
Canada is a North American country consisting of ten provinces and three territories. Located in the northern part of the continent, it extends from the Atlantic Ocean in the east to the Pacific Ocean in the west, and northward into the Arctic Ocean...
airspace, Newfoundland
Newfoundland and Labrador
Newfoundland and Labrador is the easternmost province of Canada. Situated in the country's Atlantic region, it incorporates the island of Newfoundland and mainland Labrador with a combined area of . As of April 2011, the province's estimated population is 508,400...
specifically, or instructed to return to their point of origin. For those mid-flight aircraft unable to land safely due to excessive fuel weight, dumping became necessary.
Dump-and-burn
A dump-and-burn is a fuel dump in which the fuel is ignited, intentionally, using the plane's afterburnerAfterBurner
The AfterBurner is a lighting solution for the Game Boy Advance system that was created by Triton-Labs.Originally, portablemonopoly.net was a website created to petition Nintendo to put some kind of light in their Game Boy Advance system...
. A spectacular flame combined with high speed makes this a popular display for air show
Air show
An air show is an event at which aviators display their flying skills and the capabilities of their aircraft to spectators in aerobatics. Air shows without aerobatic displays, having only aircraft displayed parked on the ground, are called "static air shows"....
s or as a finale to fireworks
Fireworks
Fireworks are a class of explosive pyrotechnic devices used for aesthetic and entertainment purposes. The most common use of a firework is as part of a fireworks display. A fireworks event is a display of the effects produced by firework devices...
. Dump-and-burns are also referred to as "torch
Torch
A torch is a fire source, usually a rod-shaped piece of wood with a rag soaked in pitch and/or some other flammable material wrapped around one end. Torches were often supported in sconces by brackets high up on walls, to throw light over corridors in stone structures such as castles or crypts...
ing" or "zippo
Zippo
A Zippo lighter is a refillable, metal lighter manufactured by Zippo Manufacturing Company of Bradford, Pennsylvania, U.S. Thousands of different styles and designs have been made in the seven decades since their introduction including military ones for specific regiments.-Establishment:George G...
s".
General Dynamics F-111
General Dynamics F-111
The General Dynamics F-111 "Aardvark" was a medium-range interdictor and tactical strike aircraft that also filled the roles of strategic bomber, reconnaissance, and electronic warfare in its various versions. Developed in the 1960s by General Dynamics, it first entered service in 1967 with the...
aircraft have been used for this purpose in Australia
Australia
Australia , officially the Commonwealth of Australia, is a country in the Southern Hemisphere comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands in the Indian and Pacific Oceans. It is the world's sixth-largest country by total area...
during the closing ceremony of the 2000 Summer Olympics
2000 Summer Olympics
The Sydney 2000 Summer Olympic Games or the Millennium Games/Games of the New Millennium, officially known as the Games of the XXVII Olympiad, were an international multi-sport event which was celebrated between 15 September and 1 October 2000 in Sydney, New South Wales, Australia...
and (until 2010) regularly at Brisbane's Riverfestival
Riverfestival
Riverfestival, which began in 1998, is a week-long festival held in September each year at South Bank Parklands and surrounding areas , to celebrate the Brisbane River. In 2009, the festival merged with Brisbane Festival....
.
See also
- Drop tankDrop tankIn aeronautics, a drop tank is used to describe auxiliary fuel tanks externally carried by aircraft. A drop tank is expendable and often jettisonable...
(external tank that can be jettisoned when empty or in an emergency) - Samoan ClipperSamoan ClipperSamoan Clipper was one of ten Pan American Airways Sikorsky S-42 flying boats. It exploded over Pago Pago, American Samoa, on January 11, 1938, while piloted by famous aviator, Ed Musick. Musick and his crew of six died in the crash....
(in-flight explosion) - Air New Zealand Flight 103Air New Zealand Flight 103On December 22, 1978, a small Cessna aircraft, piloted by Jay Prochnow, became lost in the Pacific Ocean . The only craft in the area that was able to assist was a commercial Air New Zealand flight...
(use of fuel dumping in an attempt to make the aircraft more visible)