In an internal combustion engine, fuel starvation is the failure of the fuel system to supply sufficient fuel to allow the engine to run properly, for example due to blockage, vapor lock, contamination by water, malfunction of the fuel pump or incorrect operation, leading to loss of power or engine stoppage. There is still fuel in the tank(s), but it is not delivered to the engine(s) in sufficient quantity. By contrast, fuel exhaustion (also called fuel depletion) is an occurrence in which the vehicle in question becomes completely devoid of usable fuel, with results similar to those of fuel starvation.
All modes of transport powered by internal combustion engines can be affected by fuel starvation, although the problem is most serious for aircraft in flight. Watercraft are also at risk, as a drifting vessel cannot maneuver to avoid a collision or prevent itself from running aground. On aircraft, fuel starvation is often the result of incorrect fuel management, for example by selecting to feed the engine from an empty tank while fuel is present in another one.
When the fuel level is low, some aircraft are vulnerable to a specific type of fuel starvation known as unporting, which occurs when hard maneuvers, a steep climb, or a departure from coordinated flight causes the fuel to slosh away from the line leading to an engine. Some aircraft have special operating limitations on steep climbs with low fuel due to this concern.
Aircraft with fuel tank filler caps on the surface of the wings or fuselage are also susceptible to fuel exhaustion if a filler cap is left off or not refitted correctly after removal. On an aircraft in flight, the airflow over the wing or fuselage leads to air pressure outside the fuel tank being lower than inside; as a result fuel can be sucked out of the tank. In addition to improper fitment, lack of maintenance of an aircraft fuel tank filler cap is also an issue. A defective seal on a cap may allow water into the tank when an aircraft is washed or parked outdoors in wet weather, leading to fuel starvation.
Fuel emergency procedures in aviation Aircraft operators and aviation regulatory authorities have developed various procedures that should be used during a fuel exhaustion situation in flight so that the aircraft maximizes its chances of completing a safe and successful landing.
During flight, if the pilot of their aircraft determines that they are able to follow cleared instructions and successfully complete an approach and landing, but that any further undue delay may result in the aircraft encountering a fuel emergency or landing with less than their calculated final reserve fuel, the pilot shall inform air traffic control by declaring MINIMUM FUEL. This will inform ATC that any further delay might place the aircraft in a fuel emergency situation, however this is only an advisory declaration and gives ATC no obligation or requirements to prioritize that aircraft for an expedited approach or immediate landing.
If during flight, the pilot of their aircraft calculates that they will be landing with less than their final reserve fuel, or that they will encounter a fuel emergency situation, they must inform ATC by declaring MAYDAY MAYDAY MAYDAY, FUEL. As with any other mayday call in aviation, this will be treated as a full emergency and the pilots will be provided all available aid to execute a safe and successful landing. This may include immediate prioritization above all other aircraft traffic, permission to land on any usable runway and preparation of airport emergency services at the airfield.
Fuel exhaustion and starvation incidents on aircraft Many incidents have happened on aircraft where fuel exhaustion or starvation played a role. A partial list of these incidents follows: 1940s
On April 4, 1943, Lady Be Good, a Consolidated B-24D Liberator, crashed in the desert of Kufra District, Libya. The aircraft had overflown its intended landing site and continued to fly south for several hours until it exhausted its fuel, whereupon the crew bailed out. Lady Be Good crashed in the desert, splitting into pieces, but remained well-preserved for over a decade and a half before its rediscovery in 1958.
1950s and 1960s On 19 June 1954, a Convair CV-240 aircraft operated by Swissair registered HB-IRW ran out of fuel over the English Channel near Folkestone. The aircraft ditched in the Channel, killing three passengers. Four crew members and two passengers were found alive after the crash.Aviation Safety Network HB-IRW page Retrieved: 6 December 2007. On 3 August 1954, a Lockheed Super Constellation of Air France registered F-BGNA was diverted to Boston after being unable to land at New York-Idlewild Airport due to bad weather. It ran out of fuel before reaching Boston and made a belly landing in a field. There were no fatalities.Aviation Safety Network F-BGNA page Retrieved: 12 December 2007. On 21 August 1963, a Tupolev Tu-124 operated by Aeroflot experienced a landing gear malfunction after taking off from Tallinn Airport. On finding that the nose gear could neither be retracted nor extended, the crew diverted the flight to Leningrad where they prepared for an emergency landing by circling the city burning off fuel. While circling the city the crew made repeated attempts to get the landing gear to lock down; they possibly became over-preoccupied with this and the aircraft ran out of fuel. The crew ditched the aircraft in the Neva River. There were no fatalities.Aviation Safety Network CCCP-45021 page Retrieved: 12 December 2007. On 17 November 1964, a Dutch F-104 Starfighter crashed into a mountain in Norway when it ran out of fuel following the death of its pilot. The pilot died due to malfunction of the oxygen mask. On 4 June 1967, A British Midland Canadair C-4 Argonaut registered G-ALHG suffered a double engine failure due to a fuel tank selector problem over Stockport, England. The aircraft crashed and 72 of the 84 on board died.Aviation Safety Network G-ALHG page Retrieved: 6 December 2007.
1970s and 1980s ALM Flight 980 was a Douglas DC-9-33CF flying from John F. Kennedy International Airport in New York City to Princess Juliana International Airport in St. Maarten, in the Netherlands Antilles, on 2 May 1970. Multiple diversions due to severe weather conditions and several unsuccessful landing attempts depleted the aircraft's fuel to the point where the crew believed there was insufficient remaining to reach an alternative airport and decided to ditch the DC-9 in the Caribbean Sea. There were 23 fatalities among the 63 on board. On 4 October 1975, a chartered Cessna 310Q crashed on final approach to New Hanover County Airport while transporting wrestlers Bob Bruggers, Ric Flair, Johnny Valentine and Tim Woods and promoter David Crockett to a professional wrestling match in nearby Wilmington, North Carolina. Bruggers and Flair were seriously injured, while Valentine was paralyzed and the charter pilot subsequently died of his injuries. The aircraft was overloaded and its center of gravity was beyond the aft limit; attempting to mitigate these problems, the pilot drained fuel before the flight, and the aircraft consequently ran out of fuel short of the runway. On 20 October 1977, the band Lynyrd Skynyrd performed at the Greenville Memorial Auditorium in Greenville, South Carolina, and boarded a Convair CV-240 airplane to take them to Baton Rouge, where they were to perform at Louisiana State University. The plane ran out of fuel near the end of the flight and crashed, killing both pilots and four of the 24 passengers, including the band's lead singer Ronnie Van Zant. On 2 December 1977, a Libyan Arab Airlines Tu-154 leased from Balkan Bulgarian Airlines ran out of fuel and crashed near Benghazi, Libya. 59 passengers were killed. On 28 December 1978, United Airlines Flight 173, a Douglas DC-8-61 en route from Denver, Colorado, to Portland, Oregon, experienced a landing gear indicator light malfunction while preparing to land. The aircraft continued to circle in the vicinity of Portland while the crew investigated the problem, but it ran out of fuel and crash-landed in a sparsely populated area, killing 10 and seriously injuring 24 of the 181 on board.Aviation Safety Network N8082U page Retrieved: 6 December 2007. On 23 July 1983, due to a chain of events and mistakes, Air Canada Flight 143, a Boeing 767-200, was fueled using pounds as the unit of measure instead of kilograms, resulting in only half the required amount of fuel being on board. The aircraft used up all available fuel and glided to Gimli Industrial Park Airport where the airliner landed safely. The aircraft (now scrapped) became known as the "Gimli Glider."Aviation Safety Network C-GAUN page Retrieved: 6 December 2007. A Cessna 208A Caravan, used for skydiving operations at Jenkinsburg, Georgia, crashed following a loss of engine power just after taking off on 29 September 1985. The aircraft had been refuelled with contaminated fuel; all 17 occupants died.Aviation Safety Network N551CC page Retrieved: 12 December 2007. After a string of mistakes and omissions by the pilots, a Boeing 737-200 operating Varig Flight 254 on 3 September 1989 strayed hundreds of miles off-course, ran out of fuel, and crashed in Brazil's Amazon jungle killing 13 of the occupants. Due to the crew's mistake in flying the aircraft west (270°) instead of north-northeast (027°), the aircraft was not found until four survivors walked onto a farm two days later.Aviation Safety Network PP-VMK page Retrieved: 14 December 2007.
1990s and 2000s On 25 January 1990, Avianca Flight 052 was in an extended holding pattern over John F. Kennedy International Airport in New York City due to fog and congested traffic. The Boeing 707-320B was delayed many times before it was given clearance to land, using up almost all of their fuel. On their attempt to land, wind shear, combined with bad visibility caused them to miss the runway and execute a missed approach. However, before Flight 052 could execute another landing attempt, they ran out of fuel and crashed into Cove Neck, New York, killing 73 of 158.Aviation Safety Network HK-2016 page Retrieved: 6 December 2007. A McDonnell Douglas F/A-18A Hornet of the Royal Australian Air Force, serial number A21-41, was lost on 5 June 1991 after the pilot became incapacitated. The aircraft flew until it ran out of fuel and crashed in a remote part of Queensland. The wreckage was not found until more than three years later.Wilson, Stewart. Phantom, Hornet and Skyhawk in Australian Service. Weston Creek ACT, Australia: Aerospace Publications Pty. Ltd., 1993. .ADF Serials F/A-18 page Retrieved: 12 December 2007. The crew of Indian Airlines Flight 440, an Airbus A300B2-101, executed a missed approach procedure at Hyderabad-Begumpet Airport on 15 November 1993 due to poor visibility. During the missed approach a problem developed when the flaps would not retract fully. After some time trying to solve the flap problem and find somewhere to land near Hyderabad, the crew diverted the aircraft to Madras but because they had to fly slower due to the extended flaps the aircraft ran out of fuel. It landed in a paddy field near Tirupati; there were no fatalities among the 262 occupants but the aircraft was written off.Aviation Safety Network VT-EDV page Retrieved: 12 December 2007.