What happened
On 31 May 2025 at around 12:50 EST, the pilot of an amateur‑built Van’s RV-8 aircraft was carrying out a documented flight test program to qualify the aircraft for a Special Certificate of Airworthiness in the Experimental category. The flight was being operated in the vicinity of the Jervis Bay Aerodrome, Jervis Bay Territory, when the pilot reported that during a level turn, preparing for an accelerated stall test at approximately 3,500 ft AMSL, the engine lost all power and failed. After attempts at restarting the engine were unsuccessful, the pilot was able to configure the aircraft for a glide approach and safe landing on runway 15 at Jervis Bay.
The RV‑8 aircraft was fitted with a Textron Lycoming IO‑360‑M1B four‑cylinder fuel‑injected aeronautical engine. Inspections carried out on the engine and systems after the failure identified a loose and leaking fuel connection between the fuel/air control unit (fuel servo) and the fuel manifold valve (Figure 1). A loss of integrity of the fuel line at this point would result in the engine being starved of fuel and the power loss as sustained.
The pilot reported that since the engine’s assembly in 2023 there had been no maintenance or other activity around the fuel supply connection – leading to the conclusion that the leaking fitting may have been inadequately fastened at that time.
Figure 1: IO-360 fuel system - diagrammatical illustration
Source: https://aviationsafetymagazine.com/features/aircraft-engine-induction-systems/ (annotated by the ATSB)
Safety message
An ATSB research report Amateur-built aircraft Part 2: Analysis of accidents involving VH-registered non-factory-built aeroplanes 1988-2010 found that across this period, amateur‑built aircraft had an accident rate that was 3 times higher than comparable factory‑built certified aircraft conducting similar flight operations. Further, over half of the accidents were precipitated by partial or complete engine failures – these being significantly more common when compared with factory‑built aircraft.
Considering these findings, this well‑managed safety occurrence provides a direct reminder, to all pilots and crew of sports and general aviation aircraft, of the importance of being prepared for an unexpected partial or complete loss of power during any phase of flight. In this instance, the pilot’s operation at an altitude and position in respect of the Jervis Bay Airport provided some assurance of the ability to conduct a safe unpowered descent and landing after the engine failure occurred.
About this report
Decisions regarding whether to conduct an investigation, and the scope of an investigation, are based on many factors, including the level of safety benefit likely to be obtained from an investigation. For this occurrence, no investigation has been conducted and the ATSB did not verify the accuracy of the information. A brief description has been written using information supplied in the notification and any follow-up information in order to produce a short summary report and allow for greater industry awareness of potential safety issues and possible safety actions.