 | Inerting system: Encyclopedia II - Inerting system - Use in military aircraft
Inerting system - Use in military aircraft
Inerting systems have been used in military aircraft starting with a 1950 version of the United States' B-47 bomber jet, which sublimated dry ice to produce gaseous carbon dioxide and pump it into the fuel tanks whenever the fuel pumps were active or whenever in-flight refueling was in process. This system was implemented largely over concern over static electricity discharges during in-flight refueling, and over fires that might start during aerial combat.
During the Vietnam War, it became painfully apparent that fuel tank inerting ought to be a requirement for military jets, as thousands of aircraft were lost due to enemy ground fire; analysis indicated that fuel system fire and explosion was the major cause of aircraft loss from enemy gun and artillery fire.
Military inerting systems have used nitrogen gas (on experimental versions of the F-86 and F-100), liquid nitrogen (on the C-5A and XB-70), and halon gas (on the F-16 and F-117). The inerting system on the F/A-22 pumps the air used to pressurize the fuel tank through a filter which extracts oxygen from the air. In addition to the active inerting system that displaces oxygen, the fuel tanks of some aircraft, like the F-15, are filled with a special foam that adds weight but reduces flammability. The goal is to reduce oxygen content of the air in the tank to below 9%, down from the normal atmospheric oxygen content of 21%.
Inerting systems for most military aircraft are activated with a switch or button. Standard operating procedure is to activate the inerting system only when flying in a combat zone, as most inerting systems only have enough inert gas for about 30 minutes of use. In addition, the inerting systems of some aircraft use halon gas, which is an ozone depletion agent, so use is discouraged unless actually in combat.
Other related archives747, Airbus A320, Airbus A380, B-47, Boeing, Boeing 747, Boeing 787, C-5A, F-100, F-117, F-15, F-16, F-86, F/A-22, FAA, NTSB, TWA Flight 800, Vietnam War, XB-70, aerial combat, air conditioning, ball mill, bankruptcy, billion, carbon dioxide, cargo aircraft, dry ice, explosions, fuel, halon, inert gas, nitrogen, oxygen, ozone depletion, static electricity, steam
 Adapted from the Wikipedia article "Use in military aircraft", under the G.N U Free Docmentation License. Please also see http://en.wikipedia.org/wiki |
