16:03 29 November 02 NewScientist.com news service

Incompetence was the key factor that prevented hundreds of deaths when terrorists fired shoulder-launched rockets at an Israeli airliner on Thursday, a defence expert has told New Scientist.

A simultaneous suicide bomb attack on a tourist hotel in Mombasa, Kenya, has left 13 people dead and 15 injured. But if the two missiles fired at an Arkia 757 airliner as it took off from Mombasa airport had not narrowly missed, the tragic consequences of the coordinated attacks would have been far worse.

The plane was carrying 261 passengers and 10 crew, who would almost certainly all have died. The Al-Qaeda terrorist organisation is widely thought to have been responsible for both attacks.

The pilot of the 757 saw two plumes of smoke streak past the plane during take off. The missiles are reported to have been fired almost simultaneously from a jeep outside the airport.

Crude and unreliable

Jim O'Halloran, editor of the defence industry publication Jane's Land Based Air Defence says the launchers used were Russian-made Strela-2 rocket launchers, based on photographs of two recovered systems. The Strela-2 was introduced in 1972, but it is based on 1950s technology.

He says the system is cruder and less reliable than more modern heat-seeking rocket systems such as the US-made Stinger and the Russian Igla. But the failure of the attack is more likely to be the result of incompetence than a technical malfunction, he says.

The Strela-2 consists of a shoulder-mounted, reusable launcher fitted with an individual rocket. The rocket has a nitrogen-cooled heat-seeking system and will not fire until it has locked onto a heat-emitting target. But the heat-seeking system requires time to adjust its flight and hit its target - if the target is less than 500 metres away, it can miss.

"I think the terrorists were incompetent. If they had waited until it was higher they would probably have succeeded," says O'Halloran.

Thermal decoys

Shoulder-launched rocket attacks against civilian planes have taken place before. In 1973 an Israeli airplane in Rome was attacked and in 1983 a plot to destroy a passenger plane in Kenya was foiled. But around the world, 29 of the 42 known rocket attacks on civilian planes have hit their targets.

O'Halloran says the missile attack will mean increased pressure on airlines to consider adopting countermeasures: "In the long term airlines are going to be forced to look at the way they fly. But we're talking about extremely expensive pieces of kit."

Many military and VIP airplanes are fitted with systems capable of thwarting heat-seeking rockets. Some confuse the rocket's electronics, other use thermal decoys, such as flares or balloons. Some Israeli passenger aircraft are rumoured to also have such systems, but this has never been confirmed. Arkia has denied that its 575 airplane had such a system.

Danny Shinar, director of Israel's Transportation Ministry's aviation security division says the ministry has been developing a mechanism to protect commercial aircraft for two years, but he did not disclose details.

Another possibility would be to protect the airports, rather every individual plane, as aircraft are most vulnerable during take off and landing. But the Strela-2, for example, can strike a target 5500 metres away, so keeping attackers out of range is unlikely to be practical for most airports.

US and Israeli defence forces have successfully tested a high-intensity laser system designed to detect and destroy missiles and even artillery fire. The system is designed to fit on top of a vehicle, and so could be moved if necessary. But O'Halloran says it would probably be too expensive at present. Surveillance and intelligence are likely to be better defences, say other experts.

Will Knight

-- Anonymous, November 29, 2002