The New Zealand Civil Aviation Authority is tightening up regulations covering the commercial operation of former military helicopters in the wake of a number of accidents affecting the types.

The authority says there have been four fatal accidents and six deaths involving former military helicopters in the country since 2001. In the latest accident, in late April, a former US military Bell UH-1B Iroquois (ZK-HSF) crashed at Mokoreta, Southland, on New Zealand's South Island, killing the pilot.

The helicopter, owned by Fine Particle Application, is reported to have broken up while in flight following a crop-spraying mission. The country's Transport Accident Investigation Commission is investigating the accident.

Around 12 ex-military Hueys operate in the country and the CAA is concerned that more surplus helicopters will enter the country because of their low purchase cost as they leave the US military. These helicopters primarily conduct agricultural and logging work.

The helicopters currently operate in the restricted category of Part 21 regulations, but this is not where they belong and US military maintenance requirements are not suitable for commercial operations, says the CAA.

Instead, the authority is seeking to create a new category that would include higher airworthiness standards than those now imposed for entry into the country, an investigation of uses, and appropriate operational and maintenance requirements.

The change will need to go through the notice of proposed rule-making procedure, with the authority seeking to start the process from 1 July.

Source: Flight International