Flying for Dummies

From the Sydney Morning Herald:

THE potentially disastrous power failure on a Qantas flight carrying 344 passengers above Bangkok was caused by a blocked sink in a galley, the agency investigating the incident said yesterday.

Flight QF2 - a Boeing 747 travelling from London to Sydney - lost power from all four of its main generators 15 minutes from the airport, and the pilot was forced to switch to battery back-up for the landing, the Australian Transport Safety Bureau said.

The passengers arrived safely in Sydney yesterday, three days after leaving London.

The bureau confirmed last night that the power cut was the result of faulty drainage in the first-class galley of the 747-400, which resulted in water entering the generator control unit - the aircraft's central electrical distribution system.

Water from the blocked drain collected in a drip tray under the floor. A crack in the drip tray caused the water to leak into electrical wiring.

Each of the plane's four engines has its own generator, but the water shorted out the aircraft's power supply. A backup battery system was immediately activated.

The cabin crew on the flight will be interviewed as part of the investigation.

In a statement issued yesterday, Qantas's executive general manager, John Borghetti, said the aircraft's pilots had "handled this unusual situation in line with their training".

However, a spokesman for the Australian and International Pilot's Association, Colin Adams, said that those on the flight were "very lucky" the incident had occurred close to an airport.

"In that situation you have a minimum of 30 minutes before you lose power to the flight instruments," Mr Adams, a Qantas pilot, said. "After that the only idea that you have of airspeed and where you are in relation to what's around you is what you can see out of the window. There is no written procedure for what happens in that situation - it's the pilot and his wits.

"If you were a long way from an airfield at night it would be an extremely hazardous situation. If you were in cloud you would not know where the ground was and you could end up in an extremely dangerous situation."

Mr Borghetti said Qantas had inspected its entire fleet of 747-400s after the incident, with all aircraft cleared to fly.

However, Mr Adams said the fleet was nearing the end of its useful life. "These are 15-, 16-year-old aeroplanes that work 16, 17 hours a day. It's a bit like a car - a new one is always going to function better and be safer than an old one."

The director of aerospace at RMIT University in Melbourne, Arvind Sinha, said that a total failure of all four generators on a Boeing 747 was "unheard of".

"The engines have their own independent power source and the steering is operated by a hydraulic pump system, but the critical issues are the navigation and communication systems that you need to find your way to a runway to land," Dr Sinha said.

As news of the incident broke yesterday, the Herald received a number of reports of other technical problems on Qantas flights.

James Vozzo from Eastlakes said the take-off of his Qantas flight from JFK Airport in New York on January 3 had been aborted twice, due to a faulty cabin lock and a problem with the plane's braking system.

"We ended up sitting on the runway for 5½ hours and then they eventually had to cancel the flight," Mr Vozzo said.

Another Qantas passenger said that his flight had experienced power-generator problems that caused sweltering cabin temperatures