The International Federation of Airline Pilots' Associations said threats of legal action against pilots after disasters could harm the flow of information received by crash investigators.

The three crewman of Los Angeles-bound flight SQ006, which crashed on take-off in typhoon conditions on October 31, have been identified by Taiwanese investigators as the most likely primary cause of the disaster, which claimed 82 lives. The captain, Foong Chee-kong, selected a closed runway for take-off and sent the Boeing 747-400 barrelling into concrete blocks and construction equipment left on the tarmac.

Investigators are still looking into factors that may have contributed to Captain Foong's fateful decision, including the role of control tower personnel and airport lighting procedures.

The federation's intervention came as Singapore Airlines confirmed it had asked the Taiwanese authorities to protect crew held on the island while the cause of the crash is investigated. Media reports claiming the crew had received death threats could not be confirmed yesterday.

"What we have requested is for the authorities in Taiwan to give protection to the crew," a Singapore Airlines spokesman said yesterday. The airline had no knowledge of any specific threats against the men, the official said.

Captain Foong was accompanied on the flight deck by two first officers, Latiff Cyrano and Ng Kheng-leng. All three survived the crash physically unscathed but were described by Singapore Airlines as being "deeply distressed".

The federation said the Britain-based group "denounces, in the strongest possible terms, the growing and extremely disturbing trend of apportioning 'blame' following aircraft accidents". "The threat of civil or criminal proceedings for violations of aviation safety laws and regulations is having a profound and damaging effect on the flow of precious aviation safety information, which is essential if lessons are to be learned from accident investigations."

The federation said it had the support of more than 90 member associations around the world, and represented more than 100,000 pilots. It called for a new safety culture that would be "supportive of those who commit error . . . so that we can all learn".

The Air Line Pilots' Association of Singapore urged investigators "to maintain a conducive atmosphere for the pilots to best assist the authorities so that the cause and other contributory factors may be ascertained.