The scorched engine at the centre of the latest allegations about safety standards at Qantas is now being examined by the ATSB, the independent air safety investigator, and the credibility of two unions, the airline’s management and the air safety regulation enforcer, CASA, are all on the line.

This is because last Tuesday night’s departure of QF637, an old Boeing 737-400, from Brisbane to Melbourne, has become the media focus of a dispute in which the Qantas members of the Association of Professional Engineers, Scientists and Managers have banned after-hours call-outs because of stalled negotiations over a 30% pay rise.

One of the 737s engines went ‘bang’ and burst into flames as it was climbing past Coolangatta, causing the pilots to return to Brisbane because of what Qantas described as “unusual vibrations.”

Another Qantas union, the Australian Licensed Aircraft Engineers Association, weighed in, saying that on examination by its members the engine was found to be in urgent need of replacement. The ALAEA called for the current ATSB investigation and added that the standards of its maintenance overseas need to be probed.

As it turns out, the engine was last serviced in Melbourne by its members, but that doesn’t let Qantas off the hook in that it is legally responsible for maintaining its fleet, and the standards of whomever flies and services them, regardless of where this happens.

But the ATSB is not an industrial relations tribunal. Nor set up to apportion blame.

For those who find the media scrutiny of airline incidents unsettling, an ATSB inquiry will cut through the hype, and any agendas, and determine just what the safety issues were.

It will determine if the engine was serviced in compliance with all the regulations and standards. And whether the failure, which is claimed to have blasted fragments of the engine into the slipstream, was the manifestation of a fault which may be the result of a manufacturing defect or a previously undetected issue that may require special inspections and remedial action by 737 users world wide.

This sort of engine and airframe sleuthing by bodies like the ATSB is what keeps air travel safe from unrecognised defects in airliners.

If however the ATSB were to discover that the engine failure is related to a known condition, and that Qantas had not been on top of it, then CASA risks flack for a failure of its oversight of the relevant standards at Qantas.