Israeli authorities plan to issue a new anti-hijack identification system to incoming aircraft which they say is foolproof, but some experts are not convinced it will plug all the security holes on the horizon.

Starting next year, Israel will require pilots who fly to its airports to use the Security Code System (SCS), a local invention designed to ensure planes that have been commandeered for al Qaeda-style attacks are spotted in time.

Israel plans a trial run for the system, using a credit card-sized keypad, next month, in cooperation with five airlines from the United States, Europe and Africa. About 10,000 of the units will ultimately be issued, with Israel bearing the cost.

Pilots who fail the authentication test when they approach Israeli airspace will be denied entry. Should a plane go ahead, ignoring further warnings, Israel will consider it hostile and scramble fighter planes for an interception.

In the worst case, that could mean an aircraft is shot down.

You can't bluff this system, Dani Shenar, chief of security for Israel's Transportation Ministry, told Reuters.

It provides a higher level of confidence that the aircraft is being controlled by the right people, which is a huge asset in terms of avoiding unnecessary security alerts.

He said the system knows how to differentiate between a classic hostage-taking hijacking and a 9/11-style hijacking.

Shenar and the company that developed SCS, Elbit Systems, declined on security grounds to give details of the technology and procedures involved.

TWO KINDS OF HIJACK

Several experts familiar with Israeli methodology say the system -- also known as Code Positive -- is based on the assumption that a hijacking will take place in one of two ways.

Hijackers could either kill the pilots and take control -- as is believed to have been the case in the September 11 attacks on the United States.

Or they could force pilots to issue a compliant response to the system in the hope of buying enough time to reach Israel and crash the planes into a target on the ground.

In the first case, the hijackers would fail the security check as they entered Israeli airspace, giving military authorities about 15 minutes to launch a response.

In the second, Shenar said, pilots would be expected to relay a May Day alert. He declined to say how they would do this during a hijacking.

Omer Laviv, an aviation security expert with the Israeli company Athena GS3, said some pilots may be reluctant to signal their predicament.

That would mean certain death, while if you give the correct code, perhaps the attacker would be willing to land and to negotiate. Now, this is a big dilemma, Laviv said.

Also, Laviv said, hijackers could wait until after a plane had passed the checks and entered Israeli airspace to storm the crew, although Israel requires that all incoming airliners keep their flight deck doors locked.

GUN TO THE HEAD

Shenar said SCS's designers had taken the gun to the pilot's head scenario into consideration.

Once a pilot understands this system, he will understand that using it is his best way of handling different hijack-related situations, Shenar said. International experience shows that, in a crisis, a flight crew will do what it has to do.

The SCS keypad indicates that its user will be expected to enter a numerical code.

On the back of the device, which a Reuters correspondent inspected during an exclusive tour of the Israeli Transportation Ministry's aviation control facilities, is what looks like a microphone, labeled Acoustic Signature; that suggests there is also some kind of voice-identification technology.

Chris Yates, aviation security editor for Jane's publications, said since the system did not appear to use a transmitter he doubted it could feed live data from the flight deck to the ground.

International airliners have long been equipped with a universal transponder for emitting distress signals, something known to most hijackers by now. SCS would, at the very least, offer a novel safeguard, Yates said.

Any technology enhancing flight safety is a worthwhile addition to the arsenal we have to beat terrorists, he said.

The Israelis, from my experience, tend to keep useful initiatives close to their chests until they are ready for deployment. The reason is that all technologies have a limited shelf-life before ways and means are found to circumvent them.

He saw a potential risk in pilots issued with the system proving to be terrorist sleepers or collaborators.

There are any number of instances around the world of airline staff being involved in all manner of criminal activity, he said. And what about the threat, for example, of an unbalanced pilot?

(Additional reporting by Mark Trevelyan in London; Writing by Dan Williams; Editing by Andrew Dobbie)

Israel Security