Air NZ checking fleet for cracks

File photo / Mark Mitchell

Air New Zealand says it is checking its fleet of 15 Boeing 737-300 aircraft following the explosive decompression of a Southwest Airlines plane in the US last weekend.

All the 737s in the Air New Zealand fleet (which have an average age of 13.2 years according to the airline) are the same 737-300 model that was involved in the Southwest incident.

The planes are used on Air New Zealand's domestic mainline jet routes, mostly flying to airports between Auckland and Dunedin.

An Air New Zealand spokesman told the Australian Business Traveller website: "Fifteen of our aircraft will be checked. One aircraft needs to be checked within the next five days, and this will be completed as part of its scheduled maintenance which is already under way this week. The other 14 aircraft will be completed within the timeframe set out in Boeing's service bulletin."

Air New Zealand said the checks would not affect scheduled services.

Plane manufacturer Boeing has issued a service bulletin to all airlines using the older 737s explaining precisely what steps must be undertaken. The US Federal Aviation Administration (FAA) safety regulator has also issued an airworthiness directive, mandating that airlines follow Boeing's instructions.

Qantas was forced to ground four of its Boeing 737-400 aircraft (all older than the Southwest plane) earlier today by the Australian civil aviation authority Casa to carry out the same checks.

The Southwest jet lost part of its fuselage "skin" on a weekend flight between Tucson and Los Angeles, leaving a hole in the ceiling about 30cm wide and 150cm long, close to overhead cabin baggage compartments.

Passengers put on emergency oxygen masks as the second-generation 737-300, first flown in 1996, descended quickly to make a safe landing at Yuma airport in Arizona.

Southwest and American authorities has said that "aircraft skin fatigue" - tiny cracks in a plane's metal skin - may have caused the problem.

The FAA has required inspections using electromagnetic technology in specific areas of the fuselage on certain Boeing 737 aircraft that have flown more than 30,000 times. Southwest's jet had logged 39,000 flights - equivalent to 7.2 every day for every year it had been in service.

FAA administrator Randy Babbitt said the inspections were designed to detect cracking that could not be spotted with visual inspection, and it would then require repetitive inspections at regular intervals.

US Transportation Secretary Ray LaHood said the weekend incident was "very serious" and Southwest pulled 79 Boeing 737-300s out of service, cancelling hundreds of flights, to inspect them. After checking 67 aircraft, it had found three more with cracks.

US National Transportation Safety Board official Robert Sumwalt said the Southwest incident had revealed a previously unknown area of potential weakness: "It was not believed that this was an area that could fail."

- NZPA