What happened
On July 14, 2014, an MD 600N helicopter, registration SE-JKJ, was conducting a private VFR flight from Frösön to Bromma. While cruising at approximately 1,500 feet near Kungsängen, the engine stopped due to fuel exhaustion. The pilot, who was alone on board, initiated an autorotation to locate a suitable site for an emergency landing. During the attempt to land, the helicopter overturned, resulting in substantial damage to the aircraft. The pilot escaped the wreckage without any injuries.
The investigation
SHK investigators examined the aircraft's fuel system, maintenance records, and the circumstances surrounding the engine failure. The investigation focused on why the engine ceased operation despite having approximately 30 liters of usable fuel remaining in the tanks. Technical inspections of the engine and fuel system were conducted, alongside a review of the maintenance history provided by various continuing airworthiness management organizations (CAMOs).
Findings
- The engine stopped because the fuel transfer system failed to deliver remaining fuel to the engine.
- A clogged check valve, caused by contamination, prevented the fuel from being transferred.
- The required annual functional check of the fuel transfer system had not been performed for several years.
- The aircraft's maintenance program failed to include the updated maintenance instructions issued by the type certificate holder.
- The helicopter was technically not airworthy because the mandatory functional checks were omitted and the aircraft had undergone unauthorized external foiling/striping.
- The emergency landing was performed in a tailwind, which contributed to the severity of the impact.