Industry opposition to compulsory warning equipment persuades safety authority to let operators decide

Australia's Civil Aviation Safety Authority (CASA) is recommending that all pressurised aircraft in Australia are fitted with audible pressurisation alarms after sectors of the industry opposed mandating the systems because of cost.

The original recommendation came from the Australian Transport Safety Bureau (ATSB) after an investigation into the crash of a Beech Super King Air 200 in September 2000. The aircraft, on a charter flight from Perth to a gold mine in Leonora, crashed in Queensland after flying on autopilot for 5h after the pilot and seven passengers died, reportedly from hypobaric hypoxia.

After the ATSB recommendation, CASA issued a discussion paper on mandating audible alarms, but met "significant opposition", particularly from the Regional Airlines Association of Australia and the Australian Federation of Airline Pilots.

CASA says the problem is that for some pressurised aircraft, the modification can cost up to A$100,000 ($65,700), while for others the cost would be far less. There was also opposition on the basis of international consistency, says CASA. If Australia mandated audible alarms, it would be the only country to do so at a time when it is trying to bring its aviation regulations in line with those of Europe and the USA.

There were concerns about Australia having a unique design rule that would mean extra costs for an operator if it wanted to sell the aircraft in the USA because the US Federal Aviation Administration would require the alarm to be removed.

As a result, CASA is now recommending that pressurised aircraft have audible alarms where appropriate, allowing each operator to make a cost-benefit analysis. It says it may revisit the decision if there are more depressurisation incidents.

After the King Air incident, CASA started an educational campaign to raise awareness of pressure management and hypoxia.

Source: Flight International