The Aviation Safety Council （ASC） releases final report on investigation of an Emerald Pacific Airlines （EPA） Bell 206B3（Bell 206） helicopter, registration number B-31127, crashed during performed the power line insulators cleaning operation in Linkou District, New Taipei City.

On November 22, 2015, Emerald Pacific, a Bell 206 helicopter, took off from a temporary heliport site of Dong Ming Street, Linkou District, New Taipei City with one captain and one water cannon operator aboard to conduct the power line insulators cleaning operation. The helicopter collided with the power cables nearby during maneuvering after finishing the insulators cleaning work at one of the power transmission tower, resulted in the main rotor and the tail section pulled off from the fuselage and crashed into the farm land. The helicopter sustained totally destroy and the flight crew on board were fatally injuries.

The ASC is an independent agency responsible for civil aviation, public aircraft and ultra-light vehicle occurrences investigation. According to the Republic of China Aviation Occurrence Investigation Act and referencing to the related content of Annex 13 to the Convention of International Civil Aviation Organization （ICAO）, the ASC launched an occurrence investigation by law. The organization or agency been invited to join the investigation team also included: Civil Aeronautics Administration of Ministry of Transportation and Communications （CAA）, National Transportation Safety Board （NTSB） and Emerald Pacific Airlines. The final report was reviewed and approved by ASC’s 50th Council Meeting on October 25, 2016.

Findings related to probable causes:

1. After completion of the insulators cleaning work on Tower #24, the flight crew did not keep sufficient situation awareness to the condition of the obstacles near the operating environment. As a result, the aircraft collided with the nearby power transmission cable at the time of departure and crashed.
2. Standard operation procedures regarding the standard call and conformation may not be followed by the flight crew during the operational and departure phase. The water cannon operator may also not assist the captain in inspecting nearby terrain and obstacles.

Findings related to risk

1. The crew resource management （CRM） training of Emerald Pacific Airlines did not have the practical trainings which were based on standard operating procedures （SOP）.
2. The Emerald Pacific Airlines flight manual did not specify the detailed procedures related to the entry and departure, operating techniques and the mission abort criteria of the insulator cleaning operations, which affected the safety of operation.

Safety Recommendations

To Emerald Pacific Airline:

1. Require the flight crew to carefully inspect the terrain and obstacle near by the operational area and be vigilant and comply with the standard calls and operating procedures at all phases.
2. To produce and integrate detailed information on obstacles in the work area for flight crew to facilitate task preparation, briefing and mission conduct.
3. To develop a complete crew resource management training program, and strengthen the practical part of the training to implement the relevant training issues.
4. Clearly define the detailed procedures related to the entry and departure, operating techniques and the mission abort criteria of the insulator cleaning operations.
5. Consider the installation of a simplified flight recorder on aircraft or the installation of a cockpit video recorder in the cockpit to facilitate the review of training and operations, and occurrence investigation.

To Civil Aeronautics Administration:

1. To supervise the Emerald Pacific Airlines flight crew to observe the terrain and obstacle near by the operational area carefully and to be vigilant, and should abide by the standard calls and operating procedures at all phases.
2. To implement the requirements for the mission preparation, briefing and the procedures of mission conduct in Emerald Pacific Airlines.
3. To supervise the integrity of the crew resource management training program and supervise the implementation of relevant training issues.
4. To supervise Emerald Pacific Airlines to set up detailed procedures related to the entry and departure, operating techniques and the abort criteria of the insulator cleaning operations and to ensure compliance.
5. To assist Emerald Pacific Airlines in assessing the feasibility of installing a simplified flight recorder on aircraft or installing a cockpit video recorder in the cockpit.

To Ministry of Economic Affairs:

1. Consider the additional operation modes of insulators cleaning other than applying the helicopter to conduct the insulators cleaning operations in the case of multi power transmission cables passing through the insulators cleaning work area.

Full investigation report is available for download at http://www.asc.gov.tw

Sherry Liu, Engineer
Tel: 89127388-330 
Email:sherry@asc.gov.tw