Air safety investigators say they will look into claims signals from the base used to communication
with US and Australian ships and submarines may have interfered with the Qantas Airbus’s computer.
During the emergency the plane plunged 650 feet in seconds, injuring more than 70 passengers and crew.
The naval communications base is at Exmouth in Western Australia’s north, 30km from where the Qantas Airbus A330-300 made an emergency landing at Learmonth last week.
There were 303 passengers and 10 crew aboard when the plane suddenly dropped altitude, hurling people around the cabin and forcing the pilot to land.
The Australian Transport Safety Bureau today said it would examine whether powerful electromagnetic signals from the communications base could have sparked the emergency.
The base uses powerful low frequency radio transmissions to US Navy and Australian Navy ships and submarines.
It is understood to be the most powerful transmission station this side of the globe and includes 13 radio towers, the tallest of which is 387m tall.
The base is named the Harold E. Holt communications station after the former Australian Prime Minister.
ATSB spokesman David Hope confirmed the new line of inquiry today, after “several” groups had raised it as a possibility.
“We’re looking at everything as part of a very thorough investigation,” Mr Hope said.
“That’s been raised by a number of people to say that somehow or another this US military base has got a very high frequency signal tower there and that could somehow interfere with electrical devices – so we’ll look at it.”
The latest possibilty comes as the world’s Airbus operators were warned urgently of the autopilot failure.
The ATSB has already found that the Airbus A330-300’s air data computer – or inertial reference system – sent erroneous and spike information to the flight control computer causing the autopilot to disconnect.
The aircraft was cruising at 37,000 feet when the fault occurred, causing it to descend up to 650 feet in seconds.
Last night, the Australian Transport Safety Bureau (ATSB) said it was likely a fault in the Airbus A330-300 jet’s inertial reference unit was the cause of the incident, and it was likely to be a “unique event”.
Investigation director Julian Walsh said the faulty unit continued to feed “erroneous and spike values” to its primary computers.
“This led to several consequences, including false stall and overspeed warnings,” he said.
“About two minutes after the initial fault (the air data inertial reference system) generated very high and incorrect values for the aircraft’s angle of attack.”
This led to the flight control computers commanding the aircraft to pitch down, Mr Walsh said.
The ATSB is expected to provide a preliminary report in three weeks.
Whether other Airbus A330-300 models would be grounded would be a matter for regulatory authorities, Mr 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.”
“It’s probably unlikely there will be a recurrence, but obviously we won’t dismiss that, and it’s important that we investigate to find out what led to the (fault) and reduce the chance of that happening in the future.”
Mr Walsh said Airbus had provided advice to airlines operating the A330-300 that would minimise risk in the very unlikely event of a similar incident occurring again.
“It’s a telex that will go out to all operators around the world, and that provides guidance for the crews to take certain action when they observe certain warnings and indications in the cockpit.”
The mid-flight plunge over Western Australia is the latest in a spate of incidents involving Qantas planes.
On July 25, a faulty oxygen bottle blew a hole in the fuselage of a Qantas Boeing 747-400 flying from Hong Kong to Melbourne.
The blast caused the aircraft, with 365 people on board, to depressurise and it rapidly descended several thousand feet before making an emergency landing in Manila.
On July 29, an Adelaide-Melbourne flight returned to Adelaide when a wheel bay door failed to close, while on August 2 a hydraulic fluid leak forced a Boeing 767 to return to Sydney for an emergency landing.
On August 13, a Qantas Boeing 747-300 from Melbourne was grounded in New Zealand after an engine shut down on approach to Auckland.
HI. I have spent some time in Australia in the last couple of years. I met someone who was a geologist and had been diving out near Exmouth. (Made very unwelcome, apparently.) About early 1980s I think he said. He reckoned they must have been doing nuclear testing out their because of unnatural discolouration of rocks and shells. Then, some 2 years later I spent some time on a cattle station. They had a company there prospecting for uranium, sometimes they didnÂ¿t come up for dinner as they were out on site Â¿number crunchingÂ¿ apparently. Now, I read this a couple of days ago: http://www.bibliotecapleyades.net/tesla/esp_tesla_8.htm It is quite possible that Hayakawa and the AUM were actually eavesdropping on someone elseÂ¿s E/M weapons tests in this area. If so, the best source candidate for that Â¿someoneÂ¿ is the Â¿ex-USÂ¿, Harold E. Holt Â¿Communication BaseÂ¿ located on the northwest tip of W.A. at the Exmouth Peninsula. A large series of VLF – HF – Microwave transmitters have been built at this isolated coastal site. This is where so many reported W.A. fireball flights appear to originate. and this According to information from the real estate agent, Hayakawa drove to locations within the central areas of the properties; often over the soil- covered granites. At first he attempted to drill two small holes into the ground with a small portable rock-drill, but the drill soon failed and he had to dig small holes by spade. He placed an electrode into each of the two ground holes, connected these to a small electrical instrument about the size of a fax machine, and proceeded to record some electrical or electromagnetic variable for several hours at each site. He did not move the electrodes at all during this process. Back at the station quarters he would Â¿number-crunchÂ¿ this data all night long on a powerful portable computer. Hayakawa was reportedly aided in these field survey endeavors by female US geologist Vicky McNeil.