History of Flight
The helicopter, based at Portland, was operated by a commercial company on behalf of HM Coastguard for search and rescue. The crew came on duty at 0800 hrs and completed serviceability checks, with no unserviceabilities noted. At 1425 hrs, they received an alert and were airborne within five minutes to search for a possible person in the water in Poole Harbour. During the search, the commander maintained approximately 200 feet amsl at 30 to 80 kt, with the cabin door open and the winchman seated in the aperture. After about 40 minutes, the crew were asked to investigate a vessel emitting smoke north of their position. The commander turned to a heading of 350° at 80 kt and 200 feet.
Shortly after, rear crew members heard an unusual noise and commented on it. Almost immediately, the 'NO 2 ENG FIRE WARN' light illuminated with an audio alert. Smoke was seen under pressure from the No 2 engine exhaust area and in the cabin. The commander initiated a climb and turn towards Bournemouth Airport, 7 nm away. The sliding door was closed, and an emergency was declared. After discharging the extinguisher, the fire light remained on. Soon, the 'TRANS OIL PRESS' and 'MASTER CAUTION' lights illuminated. The co-pilot identified a suitable landing field to the left, and the commander called "Immediate Landing." During the approach to a sports field west of Poole, the 'PRI SERVO PRESS' and 'AUX SERVO PRESS' lights illuminated, and uncommanded lateral cyclic movement occurred. On final approach, the co-pilot lowered the gear and noted that the 'NO 1 ENG FIRE WARN' light had illuminated. Smoke densified as the commander made a successful landing. After touchdown, the crew shut down No 1 engine and vacated. The helicopter was destroyed by fire shortly after.
Flight Recorder Information
The helicopter had a combined cockpit and flight data recorder (FDR) recording the most recent five hours of data and one hour of voice; all data was recovered. Preliminary analysis showed the time from the initial fire warning to touchdown was 80 seconds. A Health and Usage Monitoring System (HUMS) recorder was destroyed by fire, but historical data is available for analysis.
Engineering Examination
After landing, the fire consumed about 75–80% of the helicopter before fire services extinguished it. Initial on-site examination indicated the fire began in and around the No 2 engine, with evidence of mechanical distress near the high-speed shaft. A Thomas flexible coupling in the No 2 main drive shaft had run eccentrically. Radial play at the coupling was associated with the No 5 engine bearing and/or two couplings between the power turbine shaft and main drive shaft. This radial movement caused the Thomas coupling to contact and progressively sever the tubular aft engine support, likely releasing engine oil and causing the fire. Both engines were shipped to an overhaul facility for detailed strip examination.
Additional Information
The helicopter (Sikorsky S-61N, G-BBHM) had a total time since new (TSN) of 29853:55 hours and 26465 landings as of 14 July 2002. The No 2 engine (General Electric CT58-140-2, serial number 295289, year of manufacture 1980) had a TSN of 13417:14 hours and a time since overhaul (TSO) of 1562:58 hours and 8002 cycles. The last major work in the affected area was a Main Rotor Gearbox change in November 2001 at 29754:40 hours TSN, about 100 hours before the accident.