NTSB Identification: SEA02FA030
14 CFR Part 91: General Aviation
Accident occurred Sunday, January 20, 2002 in Baring, WA
Probable Cause Approval Date: 04/18/2003
Aircraft: Agusta A109A II, registration: N55NW
Injuries: 1 Serious.

NTSB investigators either traveled in support of this investigation or conducted a significant amount of investigative work without any travel, and used data obtained from various sources to prepare this aircraft accident report.

The pilot aborted his mission due to snow, rain and foggy conditions and the aircraft remained overnight in an open field. The following morning the pilot departed to return to his base and shortly after takeoff he radioed that he had lost power in the #1 engine. He returned to the departure site and about 200-300 feet above ground lost power in the #2 engine. The rotorcraft pitched nose down and landed hard. A witness reported a mix of rain-snow, freezing temperatures and low ceilings at the time of the accident. Post-crash examination of the aircraft revealed no mechanical malfunctions. A laboratory examination of fuel from several sources within the rotorcraft as well as both airframe fuel filters revealed no significant anomalies. Both engines were test run at the manufacturer's facility with no indication of any mechanical problem and the #2 fuel control unit was flow checked and examined. The RPM WARN CB was observed to be tripped at the accident site and tests demonstrated that with this CB out, the engine failure and low rotor RPM lights and horns were inoperative. The engine DEICE locking toggle switches (engine anti-ice system switches) were observed in the off position at the accident site. The Flight Manual contained no Height-Velocity Diagram for a two-engine inoperative condition.

The National Transportation Safety Board determines the probable cause(s) of this accident to be:

The sequential non-mechanical total loss of power in both engines 1 and 2 for undetermined reasons and the pilot's failure to maintain adequate rotor RPM to prevent a hard landing. Contributing factors were the tripped "RPM WARN" circuit breaker which disabled the engine failure and low rotor warning lights and aural warnings.

Full narrative available

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