Stopping Them by Remote Control

The search continues for measures to deny would-be hijackers access to planes and to frustrate their efforts if they make it on board. Beyond strengthening cockpit doors and arming crews with stun guns or other suitable means of defense, we cannot escape the more basic issue: what to do if the crew is overpowered. In that situation, the task is to create what the military calls a “fail-safe” system.

Unlike most aspects of the war on terrorism, which require complex political and military responses, there may be a technical fix that can prevent the diversion of commercial aircraft to deadly purpose.

The concept is relatively simple: Once hijack alarms are installed in cockpits, it should be impossible for a hijacker to control the plane’s course.

There are several ways in which this might be done.

Ideally, planes would have multiple devices to signal that hijackers are taking over the cockpit, such as accessible buttons activated by the crew along with, perhaps, messages sent automatically in the event of a forced entry into the cockpit.

Once a coded signal was transmitted, an on-board computer could freeze the plane on autopilot, pending release by the insertion of a prescribed code.

One option would be to pre-program each aircraft before takeoff with a safe, automatic course to be flown if the hijack alarm were activated.

“Safe” would not mean that the lives of the passengers would be assured. It would mean that no hijacker could turn an aircraft into a weapon against targets on the ground or in the air.

A system of this kind also would respond to the specific concerns associated with Reagan National Airport’s proximity to key national facilities. The pre-set program could ensure that any attempt to divert a plane as it departed or approached the runway would simply move it onto a route away from potential targets.

While the code enabling resumption of control by the cockpit might be available to the pilot, it would be wiser to require that such a code be held by ground controllers and made available only on receipt of reliable confirmation that authorized flight personnel were again in command of the aircraft. Requiring intervention from the ground would deny a hijacker the option of extracting the release code from the crew by threat or torture. And, to discourage the killing of crew members, the procedure might call for at least two of them to signal that the pilot had regained control.

The concept is problematic. For many reasons, one would hesitate to remove control of a plane from the pilot. If a pilot could regain control only by authorization from the ground, then it would be essential to devise highly secure and redundant communications to enable necessary codes to reach the plane.

More elaborate possibilities for the future might permit ground control to force the aircraft into an automated landing routine, but for the near term it should be relatively simple to provide alarms that would block hijackers from setting an aircraft on an impermissible flight path.

The scheme’s advantage is clear: The technology would frustrate hostile takeover by hijackers bent either on using the plane for attack or flying it to a destination of their choice.

Most important, installing and advertising such arrangements should help deter hijacking.

Another aspect of the idea is worth noting. By denying hijackers the ability to redirect an aircraft, the proposed system might spare authorities the dreadful decision of having to shoot it down.

To implement safeguards of this type would require close study and evaluation, but they represent one concrete measure to cope with the specific danger that became so real in New York and at the Pentagon.