What happened
On October 7, 2002, a BK-117 helicopter, registration B-77088, operated by Chung Hsing Airlines, crashed in the mountainous area near Xinda Pond in the Wuling Farm region. The aircraft was performing an aerial survey mission for a construction company, carrying a crew of three (pilot, co-pilot, and mechanic) and six passengers.
At approximately 09:47, the aircraft was observed at an altitude of about 10,000 feet over Wuling Farm. During the survey mission between Taoshan and Pintian mountains, the pilot initiated a climb at 09:55 to perform a power check. Following this maneuver, the aircraft maintained an altitude of approximately 10,500 feet. At approximately 10:00, the helicopter lost control and crashed near Xinda Pond.
The investigation
The investigation examined the flight crew's performance, the aircraft's technical status, and the operational procedures of Chung Hsing Airlines. The investigation established that the aircraft was airworthy and all required airworthiness directives had been implemented. The flight crew held valid licenses, and there was no evidence of impairment due to fatigue, drugs, or alcohol. The aircraft's weight and balance at departure were within limits.
However, the investigation revealed significant operational deficiencies. There was a lack of communication between the airline's business staff and the flight crew, meaning the crew did not fully grasp the detailed flight plan on the day of the mission. Furthermore, the dispatcher failed to accurately verify the weight calculations and weather conditions. The investigation also noted that the crew did not adhere to the safety requirement of maintaining at least 500 feet of clearance from the ground and failed to properly execute passenger safety briefings and weight/balance verification duties.
Findings
- The flight crew operated the aircraft outside of its performance limitations, failing to maintain sufficient power while descending and decelerating, which led to a loss of control.
- The crew lacked sufficient understanding of the aircraft's performance capabilities as outlined in the flight manual.
- There was inadequate Crew Resource Management (CRM), specifically regarding the lack of mutual monitoring between the pilot and co-pilot regarding altitude and terrain clearance.
- Commercial pressure from the client influenced the crew to alter the established flight plan.
- The airline's operations manual lacked specific regulations regarding high-altitude flight limits and procedures for calculating performance for such missions.
Safety action
To Chung Hsing Airlines:
- Strengthen crew awareness of high-altitude flight performance and commitment to safety regulations.
- Improve communication and information exchange between business and flight operations.
- Implement a verification mechanism for weight and balance calculations.
- Revise the operations manual to include specific provisions for high-altitude flight, cockpit seating, and mission briefing procedures.
- Enhance Crew Resource Management (CRM) and specialized mission training (e.g., mountain flying and external load operations).
To the Civil Aeronautics Administration (CAA):
- Strengthen oversight of general aviation operations, specifically regarding aircraft performance and operational limitations.
- Review safety regulations and training requirements for helicopter operators performing specialized missions such as aerial surveys and external load operations.