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KUALA LUMPUR – The fatal Double Six air crash in Sabah nearly 47 years ago happened as a result of “unusual” technical difficulties, according to the newly declassified final investigation report on the tragic incident.
The report, which was declassified on April 6, concluded that miscalculations surrounding the centre of gravity involving the aircraft’s tail were the “probable cause” of the accident which killed then Sabah chief minister Tun Fuad Stephens and 10 others.
“The report concludes that the probable cause of the accident was due to a centre of gravity position well outside the aft limit.
“This caused the control column to run out of forward range as the nose pitched up when the flaps passed through 25° on the final approach to land,” the report stated.
It also said that while the approach to select 25° of flap was “unusual” and “not recommended”, as normal practice is to move directly to the landing flap (40°) position, Sabah Air’s Nomad N-22B 9M-ATZ was fitted with a spring-loaded flap selector which stops the flaps at a particular position when the selector is released.
“In this particular case, it is highly probable that the pilot was selecting a 40° landing flap when he was forced to release the flap selector and place two hands on the control column.
“(This could be because) the column forces had increased considerably with the nose still rising, causing loss of airspeed followed by the stall and a spin,” it said.
The report was signed by then accidents chief inspector and Civil Aviation Department flight operations director Omar Saman.
In considering the factors which led up to the deadly situation, the report noted that when the flight took off at 6.35am on June 6, 1976, pilot Gandhi Nathan had already been on duty for an official time of 11 hours and 7 minutes – in excess of the company’s 10 hours duty period.
“There was some suggestion by a witness that he (Nathan) was tired, but this is inconclusive as it is not known how much sleep he had that night.
“It is possible that he was suffering the effects of his previous evening’s food because he specifically complained of feeling unwell (prior to the flight),” it said, adding that if Sabah Air had properly monitored its crew’s rest period, Nathan would not have been required to carry out his final flight.
Procedures not adhered to
Besides that, the report highlighted how operating procedures carried out by Sabah Air pilots had “become quite casual and were certainly not of a professional standard”.
It said that specific legal requirements which state that load sheets must be prepared with a copy left on the ground before each public transport flight was not carried out on this occasion, and it was not clear if any Sabah Air pilot ever raised one.
It also noted that Sabah Air had never made an application to secure ministry approval to use the Nomad-type aircraft.
“A VIP flight, according to the Company Operations Manual, required that an IFR (instrument flight rules) flight plan be filed; this, again, was not done.
“It is quite obvious that many of the procedures listed in the operations manual have not been used by pilots. The company should have a monitoring system to cover such problems,” it recommended.
While the report also said that the technical log entries were of “such poor standard” which rendered the document “meaningless,” it conceded that Nathan might have been in the dark over the amount of baggage on the plane.
“Thus the scene appears to have been set where this pilot, not in the habit of completing many of the requirements or procedures called for by the company, did no more than a casual walk around of the aircraft in Labuan.
“He then sat in the cockpit when the final loading was completed, oblivious to incorrect load distribution.
“Against this backdrop of VIP passengers boarding the aircraft and many other people evidently standing around, it is possible that the pilot was not in control of the landing.
“It is, of course, not known what pressures were on the pilot – with such important passengers – to get on with the flight,” he however stressed, adding that while the flight was not “grossly overweight,” it was “grossly outside” the aft limit.
No sign of prior defects
Furthermore, the report pointed out that probes into Nathan’s history indicated that he had “some difficulty” in passing both ground and air tests as he only succeeded in gaining a Nomad endorsement on his licence four months before the fatal crash.
This, the report said, came after a series of “poor-write ups from the company check pilots”.
It also surmised that besides there being no evidence of any pre-crash defect or malfunction of the aircraft, its engine or service was a “causal factor” of the crash. There were also no signs of sabotage, fire or explosion.
Last week, Prime Minister Datuk Seri Anwar Ibrahim announced that the report would be declassified, just weeks after the federal government filed an appeal to overturn the Kota Kinabalu High Court’s order to declassify the report into the crash.
State ministers Datuk Salleh Sulong, Datuk Peter Mojuntin and Chong Thien Vun were among those who perished in the air crash on June 6, 1976.
They were on a flight from Labuan when the aircraft crashed in Sembulan while approaching the Kota Kinabalu International airport. – The Vibes, April 20, 2023