The Aviation Safety Council （ASC） releases final report on investigation of an Emerald Pacific Airlines BELL-206B3 helicopter, registration number B-31118, crashed during conducting an aerial filming mission on Ranch Sie-Jin, Hualien County.

On June 10th 2017, an Emerald Pacific Airlines helicopter, type BELL-206B3, registration number B-31118, was conducting an aerial filming mission by Above Taiwan Cinema, Inc. at southern Taiwan and Hualien-Taitung area. The helicopter took off about 1045hrs from Temple Fah-Lin, Chishang Township, Taitung County. There were 1 pilot and 2 aerial photographers, total of 3 people on board. Around 1154hrs, the helicopter crashed on Ranch Sie-Jin, Hualien County, the helicopter was destroyed by fire, the 3 people on board sustained fatal injuries.

According to the Republic of China （ROC） Aviation Occurrence Investigation Act, and the content of Annex 13 to the Convention on International Civil Aviation, the Aviation Safety Council （ASC）, an independent aviation occurrence investigation agency, was responsible for conducting the investigation. The investigation team also included members from Bell Helicopter, Rolls-Royce, CAA Taiwan, and Emerald Pacific Airlines.

The 'Draft Final Report' of the occurrence investigation was, in accordance with the procedures, reviewed at ASC's 70th council meeting on August 31st, 2018 and then sent to relevant organizations and authorities for comments. After comments were collected and integrated, the final report was reviewed and approved by ASC's 72th council meeting on October 18th, 2018.

The helicopter was not equipped with a flight recorder, lacking flight operational conditions and engine status prior to the crash.  Wreckage and engine examinations are also limited due to post-impact fire that burned out majority of the fuselage. A numerical simulation on wind condition cannot be validated without adequate observed data.  Therefore, the investigation was done according to interviews, maintenance records, site survey, limited wreckage examination, medical examination, simulation tests and onboard video recording analysis to determine the probable causes and risks associated with this occurrence.

The investigation shows, the aircraft was unable to recover at low altitude below 500 feet, and made impact with the ground with an abnormal descent rate at approximate 1,600 ft/min, 25 degrees glide angle and 40 knots ground speed. The probable causes of the occurrence are determined to be combined factors including, the residual Chlorpheniramine concentration of 24 ng/mL found from captain's blood test, high flight time, long duration of helicopter vibration, low altitude and mountainous area operation, high temperature in cockpit, which all possibly caused the captain fatigued, or was in a state of reduced mental or physical performance.  However no direct evidence is able to illustrate effects of the above issues that could impair captain's alertness and ability to safely operate the helicopter.    

There are a total of 18 findings from the final report, and 18 safety recommendations are issued to Emerald Pacific Airlines and Civil Aviation Administration to enhance safety. The 18 recommendations cover the following: adoption of a proper guidance of medication usage for flight crew, risk assessment for helicopter operation environment, flight crew fatigue risk management, and application of lightweight recording system to enhance safety. Please see the Executive Summary for more information.

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

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