Pilots failed by navigation device

A report on the crash of Singapore Airlines flight SQ006 yesterday found that the pilots -- as an additional safety precaution -- had attempted to use a navigational device that helps pilots properly align a plane on a runway during periods of low visibility.

But the device failed to work properly because the plane was positioned on the wrong runway -- and the crew failed to realize this before taking off.

Interviews with the pilots carried out by investigators indicated that all three of the flight's pilots had believed they were on the correct runway.

"According to the cockpit voice recorder, the pilots had also mentioned five times that they were using runway 5L to air traffic controllers," said Yong Kay (戎凱), managing director of the Aviation Safety Council, which is leading the crash probe.

Though the flight crew were not required to activate a device called a "para-visual-display," a navigation aid that is mandated to be activated for take-off when visibility is less than 200m, the crew did so, Yong said.

The visibility for SQ006 on the night it crashed was 450m.

But the device failed to work properly on the night of the Oct. 31 crash because the plane was on the wrong runway.

There were two of the para-visual-displays installed in the cockpit of the doomed aircraft. It works by receiving a signal from a transmitter at the end of the runway designated for take off.

On the night of the accident, the device failed to work properly because it was on the wrong runway -- too far from where the signal was being transmitted.

The cockpit voice recorder conversation showed that the flight crew was aware of the fact that the para-visual-display, though on, was not functioning properly.

Though the pilots adjusted the aircraft to better position the plane on the runway and activate the device, the cockpit conversation showed they were aware the device had still failed to function.

But the captain accelerated for takeoff, as he concluded that visibility was good enough.

The report yesterday also revealed that some of the safety chutes on the aircraft either failed to be fully deployed, or were automatically deployed in the cabin, which presented further obstacles to the survival of those on board and might have caused further danger to passengers.

Yong said a flight attendant reported that she was almost injured by a slide deploying in the cabin. "It's just like an airbag inflating in a car and injuring the driver," Yong said.

The investigation is to be completed in December.