Australia has discovered that an engine failure on an NH Industries MRH90 transport helicopter was caused by the compressor blades fracturing after coming into contact with the engine casing.

The engine failure, on one of the NH90's two main RTM322 engines, happened on 20 April and led the Australian Department of Defence to ground its entire fleet of 11 MRH90s until the outcome of an investigation.

The helicopter's engine-maker, Rolls-Royce Turbomeca, as well as other industry parties and Australia's Defence Science and Technology Organisation, worked to identify the cause of the engine failure, the DoD says.

"We are advised the failure resulted from compressor blade fracture due to contact with the engine casing," it says.

Australian army MRH90 - Australian DoD 
© Australian Department of Defence

The MRH90 fleet was due to resume flying operations late last week.

The DoD says it has since put in place a new inspection regime and other preventative measures to ensure that there is no repeat of the incident.

Eurocopter chief executive Lutz Bertling personally wrote to the Australian government to "directly refute any suggestion that engine damage was caused by improper handling of the aircraft by Australian Defence Force pilots", it adds.

Eurocopter, the majority shareholder in the NHI consortium, is leading a bid to sell the NH90 naval helicopter to Australia.

It has been stressing the 80% commonality in avionics and airframe between the NH90 and MRH90 as an advantage in the 24-aircraft competition, where it is up against the Lockheed Martin/Sikorsky MH-60R Seahawk.

As a result of the three-month gap in training activities, the DoD has confirmed fresh slips to in-service milestones planned for the Australian army and Royal Australian Navy, which have ordered a combined 46 MRH90s.

“The impact of the engine failure combined with the workload to address some technical issues will delay the first flight at sea for [the] navy, which is now expected to occur in mid-2011,” it says. An army target for standing up one deployable MRH90 troop has also been delayed.

Source: Flight International