July 12, 2001 (The Business Times)
Not easy to overpower pilot intent on suicide
Expert witness details factors involved in regaining control of aircraft
By Donald Urquhart
CONFUSION, negative gravity, flying debris, and a cacophony of audio and visual alarms would make overpowering a suicidal pilot difficult, an expert witness testified yesterday on the seventh day of the SilkAir High Court trial.
The first thought running through a co-pilot's head would be that there was something wrong with the aircraft, said Australian aviation expert Maurice Baston, testifying for the plaintiffs in the case against SilkAir.
Capt Baston had previously been asked by Justice Tan Lee Meng to detail the factors involved in regaining control of an aircraft following a deliberate flight path deviation by one of two pilots.
Central to testimony given by the plaintiffs' expert witnesses has been the argument that the doomed Boeing 737 of flight MI 185 had been deliberately held into a nosedive by one of the pilots.
Key evidence, they said, pointed to the plane's stabiliser trim, which was pushed into the full forward position, rapidly causing the aircraft to nosedive from its cruising altitude of 35,000 to 19,500 feet - the last position recorded by radar - in 8 seconds.
'The non-handling pilot, not the wrong-doer, would be extremely surprised as to the immediate cause of the exceedance,' said Capt Baston.
'The non-handling pilot would become extremely confused and the cockpit would have dust, dirt, flight plans, drink cups, large bulky manuals displaced in the air.'
He said the non-handling pilot would not expect the manoeuvre to have been intentionally conducted, which would rob him of several vital seconds in which to respond.
During cross-examination, defence council Lok Vi Ming asked Capt Baston if, as a pilot with many people's lives in his hands, he would not be always thinking of possible emergency situations. In response, Capt Baston said this was not the case: 'My experience is that the norm is a passive flight deck.'
'The non-handling pilot, after several precious seconds would be faced with an impossible situation, finally realising the wrong-doer was intent on pushing the aircraft into a steep dive,' he said.
In such a situation the instinctive move would be for the non-handling pilot to attempt to use his own control wheel to stop the dive, and while partial control might be regained, Capt Baston said the powerful stabiliser trim could not be so easily regained.
Compounding the problems would be the very rapid rate of descent once the dive was initiated, he added. By approximately 32,000 feet the aircraft would have exceeded its normal flight envelope - or operating conditions - he said. And within another 8 to 10 seconds the flight test envelope - or maximum conditions under which the plane's control has been tested - would be exceeded.
At this point, no one knew how the aircraft would react, and eventually it would reach a 'certain point where no regaining of control is possible, no matter what is done'.
July 12, 2001 (The Business Times)
Must show pilot's suicidal intent and act: Silkair
SILKAIR began its defence yesterday in the negligence lawsuit brought by families of six victims of the MI 185 crash by saying the plaintiffs have to show that the pilot wanted to, and did in fact, commit suicide - and murder.
Only then will the plaintiffs succeed in meeting their burden of proof, said Lok Vi Ming, the counsel for Singapore Airlines' regional airline.
Mr Lok said there were too many unknowns, too little evidence and too many assumptions made by the US National Transportation Safety Board to conclude that the pilot purposely crashed the plane killing all 104 people aboard.
At the High Court hearing, he said the findings of Indonesia's National Transportation Safety Committee were correct in concluding that there was insufficient evidence to identify the probable cause of the accident.
Counsel for the plaintiffs, Michael Khoo, had highlighted that it was not necessary to establish the suicide issue because the plaintiffs' contention is that whatever actions were taken in the cockpit were reckless actions, be they related to a suicide bid or an attempt to recover from some form of emergency.