Australia’s Civil Aviation Safety Authority (CASA) has issued a new direction on the operation of aircraft with Jabiru engines, offering relief from operational restrictions provided certain requirements were met.

“The maintenance-related actions set out in the direction include adopting the manufacturer’s maintenance schedule, inspecting certain engine components and replacing engine through bolts in accordance with the relevant Jabiru service bulletin,” CASA said in a statement.

“The timing of through bolt replacement varies if the aircraft has been used in flying training”.

“Operators must continue to observe the limitations if they do not take the actions set out in the CASA direction.”

In December 2014, CASA issued limitations on operators of Jabiru-powered aircraft, including restricting the flights to daylight hours and away from populated areas.

CASA also required trainee pilots to have successfully completed engine failure exercises before attempting solo flights.

The regulator said at the time there had been about 40 identified incidents of Jabiru engine problems in 2014, ranging “from full and partial power loss and inflight engine shutdowns to rough running and oil leaks”.

In July 2015, CASA has eased one of the regulations regarding carrying passengers.

Bundaberg-based Jabiru makes four-cylinder 2200cc and six-cylinder 3300cc aircraft engines. Figures from CASA indicated about 1,100 aircraft in Australia were fitted with Jabiru engines.

CASA director of aviation safety Mark Skidmore said the new direction was developed in collaboration with Jabiru and Recreation Aviation Australia.

“CASA’s engineers have looked very carefully at engine failure data and analyses and worked with Jabiru’s engineering adviser,” Skidmore said.

“CASA and Jabiru now have a better understanding of the problems involved and this has led to the development of the new direction.

“I am pleased operators of Jabiru-powered aircraft can now resume normal operations once the appropriate maintenance-related actions have been taken.”