Airlines Lack a Foolproof Way to Detect Smuggled Explosives

The U.S. government tightened baggage checks and passenger screening after the bombing of an Air-India plane last summer, but airlines still lack a foolproof way of detecting smuggled explosives and say a search of all bags would cripple air commerce.

The bomb that exploded aboard a Trans World Airlines Boeing 727 Wednesday over Greece was hidden in a bag in the aircraft cabin, TWA officials said. The blast at 15,000 feet blew four passengers from the aircraft to their deaths.

The plane, which landed in Athens, Greece, despite a hole in its side, had taken off from the Rome airport where aviation security experts say tight baggage screening and anti-terrorist measures have been in force since a terrorist attack Dec. 27.

It is not known whether the bomb was in carry-on luggage or had been planted earlier. A significant deterrent to smuggling bombs in carry-on luggage has been that the terrorist would be among the victims.

Suspects ‘Inside Job’

“Dollars to doughnuts this was an inside job,” said Capt. Thomas M. Ashwood, a security analyst for the Air Line Pilots Assn. He suggested that a person with access to the plane likely planted the explosive as the aircraft sat on the ground. It had arrived earlier in the day from Cairo and Athens.

For the bomb to have been hidden in carry-on luggage “would require a major breakdown in what has been an intensified security net” at the Rome airport, Ashwood said in an interview.

“TWA in that part of the world is complying and fully implementing rather extraordinary security measures,” agreed Richard Lally, the top security expert for the Air Transport Assn., which represents the major airlines.

The bombing of TWA Flight 840, Lally said in an interview, “points up the irrefutable fact that acts of terrorism are directed against governments. . . . We have to recognize a government responsibility” to ensure safe air travel.

New Security Requirements

After the hijacking of another TWA flight last summer and the bombing of an Air-India jumbo jet that killed 329 people over the Atlantic on June 23, 1985, the Federal Aviation Administration imposed tighter security requirements aimed at detecting explosives in baggage. Industry sources said those procedures were used in Rome.

The FAA directives required that curbside check-in of bags be eliminated, that checked bags be matched with boarding passengers and that more bags be subjected to X-ray or physical searches.

“The fact of the matter is you cannot make a security system foolproof; you can’t even get close to it,” said the pilot union’s Ashwood.

The TWA hijacking and Air-India bombing also prompted the FAA to re-examine its research on new technology for detecting explosives. But according to several aviation security experts it probably will be at least two years before the new technology is in use at airports.

Depends on Operator

Airports, especially in regions where terrorist attacks are likely, routinely subject bags to X-ray screening or physical searches. But security experts say the accuracy of X-rays depends on the ability of the person monitoring them and that X-rays cannot detect explosives that do not have a certain shape or density.

Physical searches of all bags at a busy airport could bring air commerce to a halt, say aviation industry officials. “You don’t have enough real estate to open up all those two-suiters,” said one official.

The FAA expects to spend nearly $12 million on explosives detection research this year and about the same in 1987. This is a sharp increase over earlier spending, which averaged $1.7 million a year and dipped to $865,000 in 1983.

The two most promising approaches are a vapor detection device and the thermal neutron activation technology by which checked bags are bombarded by low-intensity neutron particles that interact with the nitrogen found in all explosives to activate a sensor.

Needs Refinement

Thermal neutron activation technology has “pretty well been proven” but needs refinement to make it suitable for airport use, said one expert. Because it uses radiation, it is not considered suitable for screening passengers.

But a vapor detection device being developed by engineers at Thermedics Inc., of Woburn, Mass., has shown promise for passenger screening. This method already is used by law enforcement officials to identify explosives residue after a bomb detonates.

While the technology has been proven, FAA officials say sensors and machinery must still be developed that can be used routinely at airports and still be sophisticated enough to differentiate molecules common to all explosives from among hundreds of billions of other molecules.