The Civil Aviation Safety Authority today released an update on the proposal to place operational restrictions on Jabiru aircraft engines.
Last Thursday, CASA issued a discussion paper that flagged intent to restrict the use of Jabiru-powered aeroplanes on reliability grounds, placing the Australian fleet in limbo.
Today's statement clarified further the regulator's position.
"CASA has identified more than 40 Jabiru engine problems and events that have occurred in 2014 alone," it said. "Fortunately, none of these events resulted in death or injury, although many certainly could have had potentially catastrophic consequences.
"Mechanical problems identified by Jabiru include through bolt, valve, cylinder and fly-wheel bolt failures.
"The contribution of particular kinds of operations, such as student training, and maintenance-related factors to some of these failures has yet to be determined.
"The data informing CASA’s consideration of these issues has been obtained from a number of sources including Recreational Aviation Australia, Airservices Australia, the Australian Transport Safety Bureau, a number of individual sport aviation pilots and Jabiru.
"Since CASA asked for comments last week on the proposed Jabiru operational limitations, additional reports of engine failures have come to light. CASA is continuing to assess these reports as well as information from Jabiru and Recreational Aviation Australia.
"CASA is endeavouring to learn more about why these engine-related issues have arisen and to identify the causes and contributing factors. Causes may relate to the design and manufacturing process, operational conditions, engine maintenance or a mix of these factors.
"In the meantime, and until the causes can be identified and addressed, the operational limitations CASA has proposed are intended to minimise exposure to the potential safety risks posed by a full or even a partial engine failure.
"CASA will continue to work co-operatively with Jabiru to address these issues. Under existing requirements, the manufacturer has important obligations in relation to these issues.
"CASA recognises there does not appear to have been any fatal accidents attributable to the mechanical malfunctioning of Jabiru engines. Under the Civil Aviation Act, CASA is obliged to exercise its regulatory powers with a view to preventing accidents from occurring."
Proposed restriction include no passenger carrying, no solo student flight and limited use over populated areas.