Declassified: No sabotage in Double Six Crash, plane was off-balance

 

The declassified federal investigation report on the 1976 plane crash that killed 11 people, including the then Sabah chief minister Fuad Stephens, found no element of sabotage.

It said an inspection of the wreckage determined that the engine was still running at the time of the crash and the aircraft controls were working. There was also no sign of a fire or explosion.

Instead, the investigating team's conclusion is that the most probable cause of the accident - dubbed the Double Six Crash - was the plane's centre of gravity being off balance.

Based on baggage recovered from the wreckage, the report estimated that there was a load of 325lbs (147.4kg) in the aft baggage compartment, exceeding the permissible load of 198lbs (89.8 kg).

Thus while the plane's calculated take-off weight was 435lbs (197.3kg) below the maximum limit, the centre of gravity was shifted too far to the rear.

This had the tendency to push the aircraft’s nose position upward, which had to be compensated by adjusting the tailplane’s trim setting beyond what is typical, and pushing the flight controls forward.

When the aircraft’s flaps were engaged in preparation for landing at Kota Kinabalu Airport, however, this additional lift could not be compensated because the flight controls were already pushed forward to its limit.

“It is therefore apparent that there was insufficient movement left of the control column to prevent the nose from moving further up. This resulted in a loss of airspeed which […] requires even further forward position of the column to correct the situation.

“Therefore at this stage, it was not possible to retrieve the situation, which deteriorated rapidly into a stall condition,” the report said.

“Stall” refers to a potentially dangerous flight condition where there is no longer sufficient airflow over an aircraft’s wings to generate lift, which can lead to a loss of control.

The report also pointed fingers at the flight's pilot Gandhi Nathan - whom it painted as having a poor track record.

The report noted that the pilot's original flying log book was allegedly burnt in June 1969, and a replacement log book was stolen in November 1975.

It also said that from the records available, the pilot had a "history of poor performance" in flying and that his training record with Sabah Air was marginal.

For his final flight, he failed to prepare the load sheet (paperwork detailing the weight of an aircraft’s passengers, cargo, and its distribution), the passenger manifest, and some of his flight plans.

Compounding matters, the report found his employer, Sabah Air, was lax in ensuring that its procedures were followed.

"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 at Labuan and sat in the cockpit when the final loading was completed, oblivious to the incorrect distribution of the load," the report said.

The report also stated that the pilot may have lacked sleep, and noted that he had told acquaintances that he was tired and suffering from a mild stomach upset.

It said the company should have recorded and monitored crew rest periods, noting that at the time of the accident, Gandhi was working 67 minutes past his 10-hour duty period.

“Had this (crew rest period) been recorded properly by the company, then this pilot would not have been required to carry out the last flight from Labuan to Kota Kinabalu,” it said.

The report also said that while Gandhi was certified to fly the GAF N-22B Nomad aircraft involved in the accident, his employer was not.

“This organisation neither had such approval for the Nomad nor had any application been made for one,” it said.

[More to follow] - Mkini