WE USED to assume that hijackers want to negotiate. Now we know that some are
ready to end their own lives in order to turn an aircraft into a fuel-laden,
200-tonne guided missile that will kill thousands. But is there anything
aviation engineers can do to thwart suicidal hijackers once they have managed to
board a plane?
One strategy is simply to keep them out of the cockpit. 鈥淗aving a locked,
reinforced cockpit door is a valid idea airlines have explored in the past,鈥�
says David Villupillai, spokesman for Airbus in Toulouse. In the US, the
influential Air Line Pilots Association (ALPA) is now backing the idea of more
robust cockpit doors, among many other measures
(see graphic).
But that won鈥檛 stop the hijacker threatening passengers or cabin crew until
the door is opened, as is thought to have happened last week. So some suggest
going further, and fitting a bulkhead that permanently blocks access to the
cockpit from the cabin. One reason for opposition to this idea is that a sealed
cockpit would also prevent cabin crew helping sick or incapacitated pilots.
Another is that it鈥檚 not compatible with the captain鈥檚 role as commander of the
whole aircraft. 鈥淐hanges would have to be made regarding the role of the
pilots,鈥� says Elizabeth Verdier at Boeing. 鈥淭hey are in charge of the emergency
egress, they are in charge of safety and they are responsible for getting every
passenger off the airplane.鈥�
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Despite these objections, ALPA is urging more research and development for
better, stronger cockpit doors. New rules could also be proposed to ensure they
are kept shut no matter what appalling threats are being made in the cabin.
But if hijackers do make it into the cockpit, is there anything that can be
done to stop them taking the controls? Hopes here are most likely to be pinned
on 鈥渂iometric鈥� technologies that can verify that the person in the driving seat
is the bona fide pilot. A range of electronic ID systems exist or are being
developed to identify an individual by taking measurements of some unique aspect
of their biology: their face, iris, fingerprint, voice pattern or even their
heartbeat. Biometrics are already used to verify staff ID at nuclear power
plants and in secure banking centres.
Wouldn鈥檛 it make sense to use similar techniques to verify the pilot鈥檚 ID?
鈥淔rankly, no,鈥� says Villupillai. 鈥淚t would be a lot of work to put on board.鈥� He
says money would be better spent on stopping the terrorist, the bomb or the gun
getting on the aircraft. He adds that any new systems in a cockpit can also
become an added distraction to pilots who already have enough to contend
with.
But some emerging biometric systems might go virtually unnoticed by the
pilot. A new heartbeat recognition system checks out your ID
remotely鈥攗sing radar. Gene Greneker and colleagues at the Georgia Tech
Research Institute in Smyrna are developing this non-intrusive biometric system,
funded by the Pentagon鈥檚 Defense Advanced Research Projects Agency. The system
bounces a very low-power radio wave off the heart, and uses the Doppler effect
to detect movements as small as half a millimetre, from which it can build up a
signature of your heartbeat.
鈥淲e鈥檝e built a desktop device that goes in a briefcase. You turn it on and
you can see the pulse of the heartbeat and a long-term respiration signature of
a person sitting several feet away,鈥� Greneker told 快猫短视频. And
such a system automatically tells you that the subject is alive鈥攁 key
factor all biometrics systems strive to take into account, says John Woodward, a
senior policy analyst at the RAND research organisation, based near the Pentagon
in Arlington, Virginia.
Any new technology鈥攅specially one involving radio waves in the
cockpit鈥攚ould have to be proven safe and regulated by the US Federal
Aviation Administration and its counterparts elsewhere. As New
快猫短视频 went to press, however, the FAA was not commenting on any new
security plans.
Can anything be done to wrest control of the aircraft from those in the
cockpit鈥攚ho may have incapacitated the pilots and/or found themselves
locked out of the controls? One option is to extend the automatic landing
capabilities of aircraft. It is already technically possible to control and land
an aircraft without the pilot. Such a system, triggered by air traffic control,
a pilot or a biometric alarm during a hijack, could land an aircraft safely at a
nearby airport in an emergency.
But such systems raise almost as many problems as they solve, and have been
ruled out in the past. Pilots and passengers have been naturally suspicious of
handing control of an aircraft to a computer in any circumstances. Then there is
the problem of flying automatically in crowded, controlled airspace where all
other aircraft are obeying directions from air-traffic controllers. And there鈥檚
the danger of the system failing or deploying accidentally. But following last
week鈥檚 attacks, it may be time to think again.
The most modern systems are designed to land aircraft in conditions close to
zero visibility, so-called Category IIIb landings. They can only be used at
airports fitted with the required instrument landing system that sets up an
鈥渆lectronic corridor鈥� through which the plane descends to the airport. All the
pilot has to do is apply the brakes and taxi off the runway. In practice,
however, automatic systems are rarely used for the entire landing. Pilots nearly
always take control for at least a few seconds before touchdown.
Automatic landing systems are not yet able to wrest control from the pilot
and land the plane in an emergency鈥攁nd pilots would almost certainly
oppose any system that could deny them ultimate control. However, systems that
override pilots are not unprecedented. Fighter pilots were at first strongly
opposed to automatic ground collision avoidance systems, which prevent them
flying their planes into a hillside. 鈥淧ilots were initially very sceptical, yet
when they tested the system they became believers,鈥� says Christopher Wickens,
professor of psychiatry at the Institute of Aviation, University of Illinois,
Urbana-Champaign. Pilots would need a similar period of adjustment to any system
designed to take over a plane in the event of a hijacking or emergency, he
says.
Uncrewed aerial vehicles (UAVs) are already capable of the kind of autonomous
flight that could one day bring passenger aircraft to the ground safely in an
emergency. For instance, the US Global Hawk, a UAV developed by the aerospace
company Northrop Grumman, is able to take off, fly for more than 24 hours, land
and even taxi back to its hangar without any human intervention. The plane is
flown entirely by two onboard computers, which take care of everything including
flight planning.
Another American UAV, the General Atomics Predator, is flown remotely by a
pilot on the ground. 鈥淚n terms of doing this with a manned aircraft, why not?
The technology I鈥檝e seen is rather rough and ready but it鈥檚 capable,鈥� says Kevin
Young, an expert on UAVs at the Ministry of Defence.
However, UAV operators accept a high level of risk that would be unthinkable
among passenger aircraft operators. And terrorists might also jam control
signals. But some believe these risks may be worth taking and should at least be
examined, given the nature of the new terrorist threat.
