Long queues at the airport departure gate waiting to go through the X-ray machines, before being subjected to a brusque body search, have become an accepted part of air travel. But as the sight of tanks surrounding Heathrow Airport last year provided a chilling reminder, terrorists do not need to slip through the security measures and actually board an aircraft to bring it down.
Since November 2002, when an Israeli airliner was narrowly missed by two shoulder-held missiles fired by suspected al-Qaeda terrorists during take-off from Mombasa airport in Kenya, security officials have been concerned by the threat of such weapons. There are believed to be up to 750,000 inexpensive shoulder-fired missiles in circulation around the world, including the Stinger missiles the CIA supplied to Afghanistan in the 1980s.
Now the US government is investing millions to research technology to counter the threat. Teams led by the UK’s BAE Systems and Northrop Grumman were recently awarded $45m (£25m) contracts from the US government’s Department of Homeland Security to develop prototype systems for protecting commercial airliners from shoulder-fired missiles.
The 18-month contracts, awarded under the department’s counter-man portable air defence systems (Counter-Manpads) programme, will see the two teams develop, test and gain Federal Aviation Administration approval for their prototype systems, based on technology already in use on UK and US military aircraft.
BAE’s team includes American Airlines, Honeywell Aerospace and Cobham subsidiary Sargent Fletcher, with the latter designing the pod to house the system. The prototype system will be based on BAE’s Advanced Threat Infrared Countermeasures and Common Missile Warning System, developed for the US Army.
The system features electro-optical sensors to detect energy produced by the launch of a missile, said Steve Dumont, business development manager for BAE’s Counter-Manpads programme. Computer processing is then used to analyse the radiation source, in a bid to ensure the object is a missile, preventing false alarms.
‘These sensors, after detecting the threat missile, cue the jamming system to the path of the inbound missile. The jam head then fires a laser to defeat the missile,’ said Dumont.
The laser sends the missile off course by blinding it, said Burt Keirstead, Counter-Manpads programme manager at BAE. ‘Imagine those times in winter when the sun strikes your windshield and there is ice on the screen, so you’re blinded. That is a little like what the missile sees when it’s trying to track the plane,’ he said.
The system is effective against all types of infrared shoulder-fired missile, and is designed to be installed on all commercial airliners. Testing is due to begin in around a year’s time.
One particular element of the system the team will be focusing on is false alarm rates, or what the company prefers to call false notification rates. While military pilots are used to dealing with false alarms, for airline pilots approaching busy international airports any missile threat is likely to be deeply unnerving, and could lead to the airport’s closure.
‘Through our processing we can detect something and unequivocally say whether it is a missile or not. We really have to get to zero, or as close to zero as we can, the cases where we need to notify the ground that there is a missile targeting an aircraft when there isn’t. We are confident we are going to get that right down, so there wouldn’t be a case where the airport had to be closed,’ Keirstead claimed.
Northrop Grumman’s proposed system, adapted from its directional infrared countermeasure (DIRCM) system already flying on UK military aircraft and Boeing C-17s in the US, will also be based on a laser. Sensors operating in the ultraviolet range search for any UV radiation that looks like a missile. A series of algorithms process the information to determine if it is a missile, and the system then communicates with a turret, directing it towards the missile’s path.
Inside the turret is a sophisticated infrared camera, which locks on to the missile and tracks its movements. A second set of algorithms can also analyse the radiation in the infrared range to confirm the identification.
A modulated laser beam is then directed into the missile seeker, turning it away from the target aircraft, said Jack Pledger, director of infrared countermeasures business development at Northrop Grumman. The company is developing the system with Northwest Airlines and Federal Express.
‘It all happens in two or three seconds. It has to happen that quickly and autonomously to ensure the system can detect, track and defeat missiles launched at very close range,’ he said.
Once the missile has been deflected from its target, it follows its last guidance signal, which is generally a command to climb. So it will continue to ascend, until its embedded timer detects there has been no impact after a set period of around 15 seconds, and causes it to self-destruct.
Ideally, as the missile is likely to be in a climb at this point, it will self-destruct in mid-air, causing no damage on the ground. But as aircraft are most vulnerable to attack during take-off or landing, the possibility of a stray missile hitting a built-up residential area such as New Jersey or Hounslow cannot be discounted.
A spokeswoman for BA said the airline’s much publicised interest in anti-missile technology would remain nothing more than interest until such issues have been resolved.
‘We are speaking to airline manufacturers to understand the feasibility of deploying anti-missile systems on aircraft we use. But we are not aware of any viable solution currently in the marketplace, and there are a number of issues to be resolved, for example how you would deploy anti-missile technology in a very built-up airport such as Heathrow. Until there is a situation where the technology is available and is proven to be safe for civilian aircraft, we will just be keeping a watching brief,’ she said.
But while Northrop’s Pledger acknowledges the possibility of deflected missiles going astray, he insists the outcome would be far less severe than the destruction of a 300-seater airliner.
Shoulder-fired missiles carry around 2-4lb of high explosives, which is only enough to create a blast site of a few feet when not travelling at speed – roughly the same as a hand grenade, he said.
Heat-seeking missiles are also designed specifically to bring aircraft down, by targeting critical systems such as the jet engines.
‘If they hit an office building they would damage an office rather than the entire building. But in a missile, just the kinetic energy of a pipe weighing 35lb travelling at Mach 2 and hitting a structure would be tremendous. Then on top of that there is the 2-4lb of high explosives,’ he said.
Safety in the event of a false alarm while the aircraft is still on the ground has also been raised as an issue by the Department of Homeland Security. But Pledger said the system has a weight-on-wheel switch, preventing its use on the ground. It also has an eye-safe laser, similar in strength to those used by dentists, he said.
‘We are using the laser as a source of infrared, to deflect missiles; we are not using high-energy lasers to blow up the missile.’
The system will be tested on a Boeing 747 and MD-11 and, like BAE, the company will be focusing particularly on reliability. In the military such systems typically have to be serviced after around 300 flying hours, but in the world of commercial airliners, time spent in the depot means the aircraft is not in the air making money.
Estimates put the cost of maintaining existing military technology at each of the US’s 400 commercial airports, including training, ground support equipment, supplies and spares, at $5-10bn (£2.7-£5.5bn) per year.
The Israeli airline El Al is able to use anti-missile technology on its aircraft as it flies out of only one airport, meaning that all its maintenance personnel can be located in one place. So the team will be working to extend the period between servicing to that of existing aircraft maintenance cycles – typically 3,000-4,000 flying hours between intensive maintenance periods.
Pledger believes carriers should adopt the technology as part of a layered approach to combating terrorist attacks, including passenger scanning at check-in and airport perimeter security. But although the Department of Homeland Security claims that adapting existing military technology will speed the development process, doubts remain over the suitability of using a military system on commercial aircraft.
A Boeing spokeswoman said existing military infrared countermeasures are incompatible with commercial air transport operations, and a greater understanding of the safety, technical, operational and economic issues involved in adopting anti-missile technology is needed.
Not least among the industry’s concerns is money. Under the terms of the Department of Homeland Security’s programme, the BAE and Northrop teams must bring down the cost of installing the expensive military technology to below $1m (£560,000) per aircraft, with an operational cost of less than $500 (£270) per flight. But even so, the cost of installing the technology on just the US’s 6,800 commercial aircraft has been estimated to be at least $10bn (£5.5bn).
Andrew Brookes, aerospace analyst at the International Institute for Strategic Studies, said too many people, particularly politicians, believe science can solve everything. Introducing anti-missile technology will only be useful as one of a number of measures to prevent an attack, he said.
‘You have got to stop these things being out on the open market, then you have got to have secure zones for aircraft in areas where they are most vulnerable, and finally devices to ameliorate the threat.’
The devices are likely to be effective against older-style shoulder-fired missiles, picked up ‘in an Afghan market’. But if terrorists are willing to invest $50,000 (£28,000) on the latest Russian technology, they might not cope too well, he said.
‘You can spend all your money on tackling one threat, and the terrorists could simply decide to move on to something else. And it is a lot of money to spend on something that in five or 10 years’ time might not work because it has been superceded.’
However, some argue that $10bn is a small price to pay to protect air travellers from missile attack. John Pike, director of defence research organisation GlobalSecurity.org, said the Department of Homeland Security is dragging its feet on the issue. Rather than spending the next few years evaluating the technology before making a decision, it should already be overseeing its manufacture, he said.
‘It’s a few billion dollars. The problem is that the homeland security field still thinks $1bn (£560m) is a big number, so you can say, “Oh it will cost billions of dollars,” and that will stop the discussion. But $10bn is one year’s budget for [national] missile defence in this country,’ he said.
Investment in the technology should be seen as an insurance policy against the destruction of the world’s airline industry by what he termed ‘evil-doers’, claimed Pike. ‘If they shot down one aircraft on one day, two aircraft on the second day, and three aircraft on the third day, how many would they shoot down on the fourth day? None, because no one would get on an aircraft.’
However, exactly who should pay for this protection remains controversial. If the airline industry is forced to pay, ticket prices will rise, potentially stifling demand for air travel. But if taxpayers are asked to cover the cost, the US government fears everybody will go cap in hand to it, expecting a payout.
‘The reason nobody wants to think about it is that they think everybody else is going to line up and ask for their security costs to be paid. But you just have to make a very simple distinction based on who is going to benefit from the protection. Having the taxpayers pay for this does not establish a precedent for them to pay for everything,’ he said.
If the US programme is successful Pike believes other countries will be pressured to follow suit and begin protecting their aircraft in a similar way, by a voting public unwilling to step on to an airliner without some reassurance that they will not become the next terrorist target.
‘You cannot get on an aircraft anywhere in the world without going through a metal detector,’ he said. ‘We are going to have to get used to the fact that preventing evil-doers from shooting down passenger planes – and paying for it – is just the way the world works now.’