Tanks tested for clues to the Qantas blast

Steve Creedy in The Australian reports that investigators have found oxygen cylinders from the same manufacturing batch as the one that exploded on a Qantas Boeing 747 near Manila.

The Australian Transport Safety Bureau will examine the cylinders for any evidence of manufacturing flaws.

But they say it is still too early to rule anything out of their investigation into the explosions that blew a hole in the side of the plane and another serious incident over Western Australia this month, despite comments by Qantas chief executive Geoff Dixon that the probes were increasingly focusing on manufacturing and design issues.

Mr Dixon made the comments to a Melbourne lunch this week about the Philippines incident and an air data inertial reference unit (ADIRU) problem that caused an A330-300 to pitch downward over Western Australia and injure more than 70 passengers, 14 of them seriously.

While noting that the A330 investigation was ongoing, Mr Dixon said it was clear it was an issue for Airbus that “potentially affects every airline operator of a range of Airbus aircraft types”.

“It appears that in both instances, the investigators are increasingly focusing on manufacturing and design issues,” he said.

But Australian Transport Safety Bureau air safety investigation director Julian Walsh said yesterday the bureau was not ruling out anything.

“The bottom line is our investigations are ongoing and we have not drawn conclusions about anything yet,” he said.

Mr Walsh earlier revealed to a Senate committee that the bureau had found a number of oxygen cylinders from the same batch as the one that exploded near Manila.

The bottom of the oxygen cylinder blew off and most of it was lost through the hole in the side of the plane.

“Obviously, it is a challenge for us to try to establish what might have caused that bottle to fail in the manner it did,” he said.

“We have tried to locate cylinders that were made in the same batch as that particular cylinder.” 

“In recent times, we have identified a number of these cylinders, six of which are currently on their way to Canberra.”

The probe into the second major incident over Western Australia is focusing on the A330’s No1 ADIRU, which has been sent to manufacturer Northrop Grumman in the US for further investigation.

The ADIRU sent faulty information to the plane’s flight computer, which caused the plane to twice pitch down sharply.

Mr Walsh told the committee that investigators were keen to find out what went wrong with the unit and how it interacted with two similar units on the plane.

“Obviously, part of the investigation will be to understand the interaction between those units, what interactions there should have been and what protections there should have been perhaps within that ADIRU to isolate the erroneous data,” he said.

Asked about the theory the aircraft could have been affected by transmissions from the Harold Holt communications base in Exmouth, Mr Walsh said initial calculations indicated this was unlikely.

He said the aircraft was about 160km from the transmitter and the amount of energy from the transmitter at that distance was “quite small”.

Mr Walsh also told the committee that at this stage there was no evidence that Qantas maintenance had any bearing on the incidents.

A Report by The Mole