Thu, Nov 01, 2018 page3

• Pilot fatigue likely cause of crash killing Chi Po-lin

  OVERWORKED? An Aviation Safety Council probe said that Chang Chi-kuang followed the eight-flight-hour rules, but was burdened with a heavy workload

  • By Shelley Shan / Staff reporter
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  Pilot fatigue and failure to maintain a safe flying altitude might have led to a helicopter crash that took the life of documentary film director Chi Po-lin (齊柏林) in June last year, an investigation by the Aviation Safety Council said yesterday.

  The accident occurred on June 10 last year, when Chi and his assistant, Chen Kuan-chi (陳冠齊), boarded a helicopter operated by Emerald Pacific Airlines to scout sites for Chi’s new documentary Beyond Beauty: Taiwan from Above II (看見台灣II) in Hualien and Taitung.

  The helicopter took off from Chihshang Township (池上) at 10:45am and crashed at 11:54am in a mountainous area near Changhung Bridge (長虹橋) in Fongbin Township, Taitung.

  All three people on board — Chi, Chen and the pilot, Chang Chi-kuang (張志光) — died in the crash.

  Council Executive Director Kuan Wen-lin (官文霖) said that the helicopter was not equipped with a flight recorder, so there was no way to tell how the pilot was managing or if there was any engine problem before the crash.

  Investigators were unable to examine wreckage from the crash because most of it was destroyed in a fire, he said.

  The council tried to determine reasons for the crash by interviewing airline staff, reviewing images recorded on Chi’s cameras and the results of the pilot’s drug test, visiting the crash site and conducting simulation tests, he said.

  The council revealed what happened during the key 137 seconds leading to the crash, during which the helicopter flew over Cawi Community (靜浦部落), Changhung Bridge and Siejin Farm (協進農場).

  Kuan said pilots operating under visual flight rules are supposed to keep the aircraft at an altitude of 152m when they are flying over mountainous areas.

  Although the helicopter maintained an altitude of between 366m and 427m as it flew from Cawi Community to Changhung Bridge, it started to drop from 427m to 274m when it was heading from Changhung Bridge to Siejin Farm.

  The helicopter was still flying at an altitude of 168m when it was 600m east of Siejin Farm, with the rate of descent being 274m per minute.

  However, it continued to drop its altitude from that point on, with the rate of descent accelerating to 488m per minute, he said, adding that it was only 87m above the ground about 10.6 seconds before the camera stopped recording,

  A normal rate of descent should be between 91m and 213m per minute, he said.

  The time recorded on the camera showed that it took about 31 seconds for the helicopter to fly 600m east of Siejin Farm to the crash site, Kuan said.

  Investigators also tried to determine if the pilot could have avoided the crash if he had quickly pulled up the collective lever, but they found that the maximum torque generated by the helicopter’s engine could only allow it to climb at a maximum rate of 396m per minute, meaning it was not enough to reverse the aircraft’s descent, making the crash inevitable, he said.

  The investigation also ruled out possible influence from the subsiding air in the valley, as the weather data on the day of the accident showed that the flight was operating in an environment influenced by an upward air current, he said.

  The airline had arranged two pilots to work on Chi’s project, with Chang scheduled for the assignment on June 9 and the second pilot on June 10, Kuan said, adding that each pilot was supposed to fly three assignments each day.

  However, on the second day, Chi asked to replace the second pilot with Chang after the second pilot finished the first assignment, because he felt he worked well with Chang, Kuan said.

  Even though Chang followed the eight-flight-hour rules by flying only 7 hours and 35 minutes in the 24 hours before the accident, he was burdened with a heavy workload as he was also the leader of the pilot team and was in charge of coordinating with the ground staff for other pilots, he said, adding that Chang might have been overworked.

  Chang’s blood was also found to have contained 24 nanograms per millimeter (ng/ml) of chlorpheniramine, an antihistamine usually used to treat allergy-induced sneezing, common cold or the flu, Kuan said, adding that it is not a banned substance for flight personnel.

  In general, a normal person would experience drowsiness and weak muscles if the blood contains only 17 ng/ml of chlorpheniramine, he said.

  However, there was no evidence that chlorpheniramine had affected the pilot’s judgement, Kuan said.
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