PARIS, Sept 12: Efforts to tighten airline security in the aftermath of the Sept 11 attacks have failed to close a glaring loophole posed by laptop computers and other gadgets, New Scientist reports.

Anyone with “a basic knowledge of electronics” could modify a laptop’s circuitry so that it can send out electromagnetic signals to disrupt the aircraft’s guidance systems, the British weekly says.

One potential target for interference would be the plane’s “guide slope” system, which calculates the angle of descent and helps the pilot land smoothly, the report, published in next Saturday’s issue, says.

The navigational zapper could also be built into a radio, tape recorder, CD player or handheld computer organiser.

The weapon would be virtually invisible. It could easily thwart a baggage security check for it would require a trained electronic engineer to spot whether circuity has been altered or substituted.

And if a terrorist used this innocent-looking arm, the pilot would probably never even know.

Even though it has been known for years that cellphones and laptops can emit low-level interference, no airline monitors for such radio emissions during flight.

Instead, pilots rely on on passengers to turn off their devices, especially during critical moments such as takeoff and landing.

In 1996, according to New Scientist, the US Federal Aviation Administration (FAA) funded a feasibility study into ways of detecting interfering signals inside aircraft cabins.

A Massachusetts company, Megawave Corp., was hired to develop a system that scans for a broad range of radio emissions inside the cabin, via sensors mounted above each passenger seat.

Megawave’s device was successfully tested, but the FAA never took the project further.

Chet Uber, a technology expert at Security Posture in Omaha, Nebraska, told New Scientist that the FAA pulled the plug on the scheme because “they’ve given commerce a higher priority than safety. This is a clear threat that has not been taken seriously enough.” No electronic gadget, he says, should be allowed inside a commercial aircraft unless the airline is sure that it is safe.—AFP