October 17, 2008 12:00am
POWERFUL signals from a secretive naval base are being probed as a possible cause of a Qantas jet plunge last week.
Air safety investigators say they will look into claims that signals from the base, used to communicate with US and Australian ships and submarines, may have interfered with the Qantas Airbus’s computer.
The plane plunged 200m in seconds during the emergency, injuring more than 70 passengers and crew.
The naval communications base is at Exmouth in Western Australia’s north, 30km from Learmonth, where the Qantas Airbus A330-300 made an emergency landing last week.
There were 303 passengers and 10 crew aboard when the plane suddenly lost altitude, hurling people around the cabin and forcing the pilot to land.
The Australian Transport Safety Bureau said yesterday it would examine whether powerful electromagnetic signals from the communications base could have caused the emergency.
The base, named the Harold E. Holt communications station after the former prime minister, uses low-frequency radio transmissions to US Navy and Australian Navy ships and submarines.
It is believed to be the most powerful transmission station on this side of the globe and includes 13 radio towers, the tallest of which is 387m.
ATSB spokesman David Hope confirmed the new line of inquiry after it was raised as a possibility.
“We’re looking at everything as part of a very thorough investigation,” he said.
The ATSB has already found that the Airbus A330-300’s air data computer — or inertial reference system — sent erroneous information to the flight control computer, causing the autopilot to disconnect.
The aircraft was cruising at 11,000m when the fault occurred, causing it to descend about 200m in seconds.
The ATSB is expected to provide a preliminary report in three weeks.
Whether other Airbus A330-300s would be grounded would be a matter for regulatory authorities, ATSB investigator Julian Walsh said.
“However, the information we have at hand indicates that this is a fairly unique event,” he said.
“These aircraft have been operating over many hundreds of thousands of hours over many years, and this type of event has not been seen before.” with AAP