History of the Flight
On 22 April 2008 at 2230 UTC, the engineer performed a Daily Check Inspection on the Bell 206B Jet Ranger helicopter, registered PK-DAT, which was to be used for joy flights. On 23 April 2008, the helicopter was operated by PT. Derazona Air Service on an unscheduled passenger flight as a joy flight from Ngurahrai Airport, Denpasar, Bali to Kintamani, Bali. The aircraft departed Denpasar at 0020 UTC carrying foreign tourists and flew for one hour, landing back at Denpasar at 0120 UTC. After refueling, at 0200 UTC the helicopter continued with four passenger tourists for a Bali Tour, with a planned flight duration of 2 hours 30 minutes. The route included Tanah Lot, Bedugul, Kintamani, and Besakih. After about 1 hour 45 minutes of flight, the aircraft experienced a power loss. The pilot made a decision for an emergency landing.
Landing and Occupant Safety
The aircraft landed in a ricefield at Pantai Kramas Area, Labih Village, Gianyar, about 60 meters from the beach, at coordinates 08° 34' 736" S 115° 21' 460" E, at 0338 UTC. The pilot and passengers evacuated safely; no injuries were reported.
Damage to Aircraft
The aircraft sustained substantial damage. The tail boom was broken. The tail rotor blades were broken. The aft right skid and forward right skid were bent, and the forward right attachment skid was torn and detached. The main rotor blade surface showed impact markings from contact with the ground, and the trailing edge of a main rotor blade was bent from impact.
Wreckage and Impact Information
Examination of the wreckage revealed the tail boom had separated. Tail rotor blade fragments were found. The main rotor blades had rotational scoring on the surface, consistent with ground impact. The skid structure showed deformation and separation.
Tests and Research
Investigation of the engine, an Allison 250-C20, focused on the fuel control system. The plumbing connection (B nut) at the Pc port of the fuel control unit was found detached. The B nut itself remained attached with torque paint still in place, indicating it had loosened during flight. The Pc port had become detached, leading to a loss of fuel control and subsequent power loss.
Conclusions
Findings
- The helicopter was properly maintained prior to the flight.
- The pilot performed an emergency landing after a power loss.
- The aircraft sustained substantial damage.
- The B nut connection at the Pc port of the fuel control unit was found detached.
Causes
The failure of the B nut connection at the Pc port of the fuel control unit resulted in the loss of power and forced landing.