Air India has blamed the now-defunct Canadian Pacific Airlines for the security lapse that led to the bombing by terrorists of Kanishka jumbo jet 22 years ago, claiming 329 lives.

Indian airline officials, Rajesh Chopra and others, testified for the first time at a public inquiry into the incident, said they should have received a passenger manifest from Canadian Pacific Air listing all the connecting travellers on a flight from Vancouver to Toronto on June 22, 1985.

Ideally, the manifest should also have listed the baggage accompanying any passengers who were supposed to transfer to Air India Flight 182 at Toronto airport and continue on to Montreal and New Delhi.

"That was the system that was in force at that time for passengers from connecting points in Canada," said Chopra, the current manager of Canadian operations for Air India.

"We have gone through the files and I didn't see any passenger transfer manifest. There was no intimation from CP Air to Air India of (even) the number of passengers connecting, leave alone the baggage," he said.

It's now known that the bomb used by Sikh terrorists to down the plane was hidden in a suitcase checked on to CP Air in Vancouver by a fictitious passenger who identified himself only as M Singh.

Singh never boarded the flight to Toronto and never had any intention of transferring to Air India - but he talked a harried CP Air ticket clerk into checking his bomb-laden bag through all the way to New Delhi. 

If the Canadian airline had forwarded its passenger list to Air India, said Chopra, it would have been possible to discover that Singh was nowhere to be found and his bag was travelling unaccompanied.

"We would have off-loaded the bag," Chopra told the inquiry headed by former Supreme Court justice John Major. Instead, the suitcase was unknowingly loaded on to Flight 182, which went down off the coast of Ireland.

The testimony on Thursday marked the latest round in a blame game that has gone on for more than two decades, as airlines, regulators, police and intelligence officers have haggled over who should be held responsible for failing to prevent the bombing.

Critics of Air India have focused on the airline's passenger and baggage handling procedures, noting that an X-ray scanner used to screen luggage in Toronto broke down the day of the flight.

It was replaced by a hand-held electronic explosives detector, known as a PD-4, that had been ineffective in tests conducted months earlier.

There has also been testimony that John D'Souza, Air India's former security chief who is now deceased, may have been motivated by economic concerns in letting the flight take off from its last Canadian stop in Montreal without better baggage screening.

An advisory panel that reviewed events for Transport Canada also suggested that Air India - unlike the Israeli airline El Al - may have been unwilling to pay the price in passenger inconvenience for more thorough security.

But the head of AI's legal department, T N Kumar, insisted there was no effort to save money by skimping on safety. "This is not based on any evidence and this is not true," Kumar testified. "We wanted security, no airline would ever sacrifice security...Air India would not victimise itself."