This time, they were lucky

In February this year, a Boeing 757 belonging to the Israeli passenger airline company El Al, entered Swiss airspace. What made the plane special was that it was equipped with an anti-missile system designed for military aircraft. Switzerland reacted swiftly, banning all aircraft equipped with the system from entering its aerospace.

Israel went on to approach EU member states, asking for permission to fly protected planes in their airspace.

Anti-missile systems might appear to be drastic for a civilian airline, but El Al had its reasons for protecting its fleet. In 2002, one of its jets, carrying 271 passengers and crew members, was narrowly missed by two al-Qaeda shoulder-launched missiles, or MANPADS (man-portable air defence systems), as it took off from Mombasa, Kenya.

El Al is not alone in seeking greater protection for civilian aircraft. Recently, there have been some signs of interest in the EU. "We have been approached by manufacturers to look at installation in planes, but so far there has been no European application. We are examining it," says Daniel Hoeltgen, of the European Aviation Safety Agency, an EU agency. "As far as the impact on the airworthiness of planes concerned, we would have to look at the issue."

In 2003, British Airways (BA) announced that it was thinking of fitting anti-missile systems on some planes, particularly for flights to Saudi Arabia. This followed the suspension of flights to Saudi Arabia after the UK's department of transport received evidence of a potential terrorist attack. The airline is still interested, but is now taking a 'wait and see' approach. A spokesperson for BA says: "There are still a few issues to overcome in terms of adapting military technology to civilian aircraft."

The current system being used for Israeli aircraft, known as 'Flight Guard', is capable of detecting an approaching missile, warning the crew and activating countermeasures to ward off weapons. The system fires so-called 'dark flares' to lead heat-seeking missiles astray. "If you want such a system, you need to look at procedures on board, the impact on operation of the aircraft, measures for ground handling of the aircraft and responses in the event of inadvertent triggering of the system," says Jude Mariadassou, deputy executive secretary of the Paris-based European Civil Aviation Conference.

"What would be the situation if you had a secured aircraft flying into a group of unprotected aircraft as a missile is being fired?" asks Mariadassou. "What would happen if the flare system was activated? The missile would be diverted, but where to? There would be risks for unprotected aircraft."

Hoeltgen points out the dangers of electronic interference. "[Anti-missile systems] could have an impact on other aircraft flying around and on the airport environment. This is a highly complex issue and there are risks involved."

At the moment, there is no European legislation covering the use of anti-missile systems. According to Hoeltgen, several organisations including the national aviation authorities would be involved in future investigations on the viability of adopting such a measure.

EU-wide safety certification would have to be created before national regulators could give permission to airlines to go ahead with installation of anti-missile systems.

Anti-missile systems do not come cheap. Back in 2003, when BA was thinking of adopting the measure, experts estimated that installing the systems would cost £1 million (1.44m euro) per plane.

A 2005 study carried out by US think-tank, the RAND Corporation, estimated that it would cost $11 billion (8.63bn euro) to install such systems on America's 6, 800 commercial airliners. Operating costs could come to $2.1bn (1.65bn euro) annually, an amount roughly equivalent to half the country's annual budget allocated to transport security.

MANPADS, on the other hand, are cheap, easy to acquire and simple to use. As governments implement ever tighter security measures, it is feared that terrorists might resort to MANPADS more frequently.

But Heinz Fruehuirth, an airline captain and technical director at the European Cockpit Association, wonders whether anti-missile systems are the best way to protect aircraft. "Because these weapons are in the hands of people who cannot be controlled, there is definitely a threat. We do believe there are prime targets like El Al, but how big the threat is for other airlines, we can never be sure," he says.

"The threat is there, but there might be a better solution. You wouldn't be able to protect aircraft against all threats unless you had a very complex system. You have to ask if the efforts required to install the system are really [proportionate to] the threat. The danger is usually close to the airport and is better monitored from the ground. It may be that we choose to install ground-based systems at airports where we would expect weapons to be used."

In February this year, a Boeing 757 belonging to the Israeli passenger airline company El Al, entered Swiss airspace. What made the plane special was that it was equipped with an anti-missile system designed for military aircraft. Switzerland reacted swiftly, banning all aircraft equipped with the system from entering its aerospace.