What happened
On 18 February 2005, an Aerospatiale SA 330J, registration ZS-RNM, was conducting an industrial aid mission for the UN-WFP in Sumatra, Indonesia. After completing a passenger drop-off and refueling at Meulaboh Aerodrome, the aircraft departed for Cali Aerodrome with six passengers on board.
While the helicopter was established in cruise flight at approximately 2,000 feet above ground level, the crew observed the red ENG 1 warning light on the 7 Alpha warning panel. The pilot noted that engine oil pressure had dropped to zero, even though oil temperature remained within normal limits. Simultaneously, the Exhaust Gas Temperature (T4) rose to 830°C. Following the emergency procedures outlined in the Pilot’s Operating Handbook, the crew retarded the No. 1 engine fuel flow lever to ground idle and shut down the engine. The crew declared an emergency and returned to Meulaboh Aerodrome, where they performed a successful landing on Runway 15. There were no injuries and no fatalities among the nine people on board.
The investigation
SACAA AIID investigators examined the aircraft's maintenance history and the mechanical state of the engine. The operator held a valid Air Operating Certificate, and the aircraft's last MPI inspection had been completed on 18 January 2005, with 63.5 flight hours accumulated since that check. Following the incident, the engine was removed and sent to South Africa for a detailed failure examination by the manufacturer.
Findings
Technical analysis determined that the engine shutdown was triggered by an over-temperature condition caused by fuel system contamination. This contamination led to the impairment of critical fuel components, such as sticky valves or flyweights, which allowed un-metered fuel to reach the nozzles. This excess fuel caused the high exhaust temperatures, which subsequently led to excessive free turbine blade creep. This creep resulted in metal-to-metal contact between the turbine blade tips and the adjacent shroud.