New Zealand is finding its five Kaman SH-2G Super Seasprite helicopters increasingly difficult to maintain, with the issue resulting in fewer flight hours than targeted.
In New Zealand's 2009/2010 fiscal year, Royal New Zealand Navy Seasprites achieved just 882 flying hours, compared with a target range of 1,240h to 1,370h, said a report issued by the nation's defence ministry.
"That target was itself reassessed during the year to 904h, in reflection of the difficulty being experienced in keeping enough helicopters available," the report said.
New Zealand aims to have three Seasprites deployed on its Anzac-class frigates at any one time. This requires that four aircraft be operational, with the fourth required for training and certification.
In October 2010 just one Seasprite was available, with two helicopters undergoing heavy maintenance and two others awaiting heavy maintenance.
© Royal New Zealand Navy
"Corrosion and vibration damage are the main maintenance issues on the Seasprite," said the ministry. "Regular operation of the Seasprite in a corrosive, salt-laden environment exacerbates maintenance issues.
"Good prevention and husbandry can slow, but not stop, the rate of airframe deterioration."
It added that "vibration damage is endemic to helicopters and worsens in line with hours flown rather than physical age. The only way to ameliorate is to lower flying hours, which is not a viable option if capability is to be maintained."
New Zealand has identified several other problems, including long lead times for spares and engineering support from manufacturer Kaman.
It also identified problems with New Zealand Defence Force training and processes.
The report makes a number of recommendations, most focused on addressing procedural and training shortcomings. It makes no mention of possibly replacing the aircraft.
The Super Seasprite entered service in New Zealand in 2001.
The Egyptian air force and Polish navy are the only other operators of the type, with Flightglobal's HeliCAS database recording them as having active fleets of 10 and three, respectively.