System manufacturers say airlines should fit them, pilots are more cautious, and very few airlines are even considering them because of high fuel prices and their economic repercussions. Yet, despite airline problems, the U.S. Department of Homeland Security (DHS) aggressively is pursuing the development of MANPADS countermeasures for use in commercial aircraft.

So just how necessary are they and how great is the threat? Moreover, if these systems are mandated, who will foot the bill? How effective would they be and who would maintain them? And, while the questions rumble on, what is the risk if such systems aren't fitted?

"The risk depends on three variables: motivation, ability and opportunity. There's no question about the first two: That's been demonstrated. But opportunity depends on available weapons," said Capt. Dennis Dolan, first vice president of the Air Line Pilots Association (ALPA) in the U.S., who chairs the association's Counter MANPADS Task Force. He made the statement at a Safety of Flight conference in Windsor, U.K., in November. According to Dolan, about 20 manufacturers produce 37 different types of MANPAD systems. More importantly, some 1% of the estimated 500,000 to 700,000 MANPADS worldwide - or 5,000 to 7,000 systems - likely are available on the black market. Mainly heat-seeking, they typically have a range of five km, an effective altitude of three km and an ultimate speed of Mach 1.5.

As for the threat, Dolan said there have been 36 confirmed attacks on commercial aircraft since 1978, 25 of which occurred in Africa, mostly against helicopters, business jets or turboprop aircraft. Missiles have hit only seven jet aircraft and six survived, he said. Although 25 MANPAD attacks have occurred in the past five years, all took place in areas of unrest. So while the risk is statistically low, the potential availability of such weapons makes the threat very real. The 36th attack, on a DHL Airbus A310 at Baghdad in November 2003, was notable because, although it brought the aircraft down, the crew and aircraft survived. But in this case, said Dolan, it was only the pilot's skill and training that made this outcome possible. It also proved that the structural integrity of large transport aircraft provided "a very favorable platform to survive major damage."

Incidents like the Aloha Airline's Boeing 737 that lost a portion of its fuselage roof and the United Airlines 747 that had a cargo door blown out, were good illustrations of this, he said. By comparison, MANPADS are unlikely to cause such great structural damage because their warheads are small - typically weighing less than two pounds. However, as the DHL incident proved, they could critically damage systems or engines.

Dolan said there are lessons to be learned. Firstly, the integrity of hydraulic systems need to be protected by fuse-plugs, which could isolate damaged sections and help retain fluid. Secondly, pilots should be trained in special situations where systems and controls are very limited, such as when it is necessary to use engine thrust alone to control the aircraft. To this end, the aircraft's flight management system (FMS) and its full authority digital engine control (FADEC) could be enhanced to assist in extreme situations. Moreover, threats still exist from attacks on the ground, which demand different solutions.

Protection Issues

Jonathan Spaul, systems engineer, Countermeasures Dispensing Systems (CMDS) Thales Group, said fitting commercial aircraft with self-protection systems could impact passengers and ground staff because putting military protection systems on civil aircraft sends out a huge message that civil aircraft are vulnerable to attack. Moreover, because these attacks can only occur around airports - when aircraft are flying low enough to shoot at - concerns would heighten about planes being shot down over populated areas. Such systems should have no effect on air traffic management, he said, but at airports, it would be necessary to have handling procedures for decoys or flares so ground vehicles, such as catering, fuel and baggage trucks, couldn't trigger the systems if they collided with an aircraft during servicing. "Aircraft operators will not need specific training courses to store and handle these devices," said Spaul, "but they will need an element of training to handle the extra workload. Consideration should also be given to how these installations impact contracted aircraft maintenance providers and the training issues which that could involve."

Current self-protection systems that use decoy dispensers, he said, have proven to be low maintenance, so they probably would be "lifed" and replaced as whole units. However, systems that used a mix of technologies might generate more difficult maintenance issues, such as the sale of sensitive technologies to airlines of "non-friendly" countries. Qantas' Group Security Manager, Patrick Gallagher, agreed saying that harmonization issues that go along with these systems need to be carefully considered. "Would it be realistic to create different classes of airlines, such as those with protected aircraft and those without?" he asked.