An emergency on a REX turbo prop flight between Sydney and Wagga Wagga last Thursday has put the air safety investigator, the ATSB, into precisely the tight spot that the ICAO audit report calls on Australia to fix.

The ATSB hasn’t yet decided if it can inquire into the incident because of the pressure on its resources.

A passenger on the 34 seat SAAB turbo-prop says, “We were around 20,000 feet somewhere between Goulburn and Canberra when there was a strong unusual smell, a thin mist in the air, and a sensation of sharply descending.

“About a few minutes we heard the pilot, muffled by his mask, say ‘We are in emergency descent’.

“It was a steep descent. Most of us looked around in the dusk below and at each other without saying anything. The two cabin crew went to the aid of a distressed woman with supplementary oxygen packs.

“They may have also assisted another passenger. Then we levelled off at I guess around 10,000 feet and soon after made our landing at Wagga Wagga.”

While the incident ending without injury to anyone and may have been caused by a maintenance error in the pressurisation system, as one insider believes, it might also be an emerging issue with an aging commuter aircraft that went out of production in 1999.

REX is the second largest operator of SAAB 340s in the world, with 45 of them, or roughly one in eight of every one of the type still in service in its fleet.

If anything is ever going to need attention in the operations of this type of airliner as it builds up its hours and fatigue inducing pressurisation cycles, REX is likely to be one of the first carriers to pick it up.

Australia is currently in breach of an ICAO treaty obligation to investigate and report on all significant accidents and incidents. It’s an obligation that exists to ensure safety issues of world wide significance are picked up before they become serious.

The ATSB is also highly regarded for its competency. It is currently deeply committed to a major investigation of a set of serious failures of air data inertial reference units found in the flight control systems of most of the world’s fleet of Airbus A330 wide bodied airliners. One of those incidents injured more than 100 people, eight of them quite badly, on a Qantas flight forced to make an emergency descent to Learmonth in Western Australia last October.

In recent years the ATSB has also led the way in making timely warnings about equipment failures or design issues in a wide range of aircraft, including Boeing 717s.

But its ranks, and funds, are so tightly constrained that it can’t do everything. This also makes Australia a black spot in terms of comprehensive aviation safety investigation, no matter how good a job it does on those incidents it examines.

Can air transport afford to have Australia even risk missing something important in a small turbo prop that is used world wide?