Qantas 'seconds away from mid-air collision'

Two Qantas planes involved in a near-miss over Adelaide on Friday were just 25 seconds from a disastrous mid-air collision, according to the Australian International Pilots Association.

QF581 was flying from Sydney to Perth at 38,000 feet and QF576 from Perth to Sydney was flying at 39,000 feet when the lower-flying craft received permission from an air traffic controller to ascend to 40,000 feet.

At that point, the collision warning computer on the other aircraft went off, advising it to climb to avoid a collision.

"The computer warning system is time-based," said Richard Woodward, vice-president of the AIPA. "But typically it's about 25 seconds head-on. It'll go "climb now" or "descend now", and that's a resolution advisory. They got one of those, so I assume they were within 25 seconds of each other.

Mr Woodward said the two aircraft would have been flying towards each other at about 32 kilometres a minute, or one kilometre every two seconds. When the warning went off, "they would have been within 10 or 15 kilometres of each other", he said.

The two aircraft ultimately missed each other by just 700 feet (213 metres), said Mr Woodward, with QF581 flying directly underneath QF576.

A resolution advisory from a collision warning computer was a "last-ditch defence", said Mr Woodward. "It's not that easy at that altitude because the closing speed is so high and if you're in cloud you wouldn't see each other anyway."

After the air traffic controller gave permission to QF581 to climb, he reversed the decision and instructed the plane to return to its original altitude.

Nevertheless, Air Services Australia confirmed on Friday that the controller had been stood down pending an investigation by the Australian Transport Safety Bureau.

Mr Woodward said he did not want to judge the action of the controller. "I wouldn't like to make any comment on why the air traffic controller gave clearence to climb when they were so close together," he said. "I can't make a judgment on what he was seeing or looking at."

The incident happened 19 kilometres west of Adelaide at 12.13pm.

Qantas had little to say about the incident, other than "the loss of separation (distance) occurred when one of the Qantas aircraft received clearance to climb from Air Traffic Control. Our pilots followed standard operating procedures in re-establishing the required separation distance following the alert from the onboard notification system. There was no impact to passengers".

However, passengers on both planes told the media yesterday that sharp adjustments in altitude could be felt. One passenger on QF576, which took evasive action, noticed a "really strong" engine thrust that was "enough to give me a bit of a fright".

Planes are supposed to maintain a minimum distance of 1000 feet vertically and five nautical miles horizontally from each other.

Mr Woodward said a recent report from the Civil Aviation and Safety Authority found about 170 breaches of this minimum distance over the past 10 years in Australian airspace.

However, computer warnings were far rarer, he said.

"Fortunately we haven't had too many of these resolution advisories from the Collision Warning Computer because it is the last line of defence," he said.