USA TODAY August 14, 2003
Jet might survive missile strike
By Fred Bayles
The British arms dealer accused Wednesday of trying to smuggle a shoulder-fired missile into the USA allegedly delivered it on the basis that it could bring down a passenger jet. Analysts aren't as certain.
Although a shoulder-fired missile could down a commercial jet, aviation analysts say a hit wouldn't necessarily prove catastrophic. (Related story: Countries' cooperation in sting unprecedented)
"There's so many variables, there's no easy answer to the question," says Al Dickenson, director of the University of Southern California's aviation safety program.
Among the variables:
.Where the missile hits: If the missile struck a commercial jet's fuel tank, it probably would cause a catastrophic explosion. If it struck the jet's tail or wing, it might make the jet impossible to control. If it struck the cabin, it could tear the jet apart.
But because the shoulder-fired missiles seek heat, a successful shot would more likely strike an engine.
Manufacturers place armor around engines to protect the rest of the jet from an engine explosion. Manufacturers test that armor by detonating small explosives inside the engine - the likely area where a heat-seeking missile would explode.
But "I don't think anyone has a scientific handle on the effects of a commercial aircraft engine being hit by a missile," says Mark Sullivan of engine maker Pratt & Whitney.
The weight of the explosive warhead is a few pounds. It can be lethal to a jet fighter because the fighter's engines are typically located within the fuselage of the jet. An explosion within the fuselage is almost always catastrophic. Because jet engines on commercial aircraft are mounted outside the fuselage, an explosion there is less likely to cause damage to the rest of the jet.
Dickenson, an investigator with the National Transportation Safety Board for 26 years, has seen cases in which jets suffered extensive damage to an engine. In some cases, the jet continued to fly. In others, secondary damage brought it down.
A large jet is also designed to withstand significant structural damage. Federal rules require that a fuselage remain intact with a hole as large as 20 square feet. Without tests, predicting what size hole a missile might cause is impossible.
.Type of missile: GlobalSecurity.org, a Virginia-based security analysis company, has logged 35 missile attacks on civilian aircraft. Those attacks caused 24 of the planes - mostly propeller-driven - to crash. It is unclear whether missiles actually struck the planes in the 11 attacks that did not result in crashes.
Older-model missile systems could not be fired until after a jet passed. That way, the missile could track the heat from the exhaust of the engine. The SA-18 Igla - the type of missile the arms dealer allegedly tried to sell - has trackers that enable it to be fired as a jet approaches the shooter. That might give a terrorist more chances to shoot. The SA-18's range is 3.2 miles. The greater the distance, the less effective the missile.
.Timing of the attack: The best opportunities to shoot at a jet coincide with the times a jet is most challenging to fly: during takeoff and landing. But commercial jets are designed to continue to fly if they lose an engine. And pilots train extensively for an engine failing on takeoff.
But firing at a jet early in flight or when it is close to landing risks failure. The missiles don't arm themselves until they have traveled at least 1,500 feet. Those knowledgeable about failed missile attacks last year in Kenya and Saudi Arabia say terrorists fired when the jets were too close to them. The missiles harmlessly passed by the jets.
Contributing: Alan Levin
© Copyright 2003, USA TODAY, a division of Gannett Co. Inc.
