Accident Overview
On August 30, 2012, a RAC’s BN-2B-26 aircraft, registration number B-68801, was contracted by Real World Engineering Consultants Inc. to conduct an aerial photogrammetry mission. The aircraft carried a captain, a first officer, and an aerial photographer. The flight plan was to depart from Songshan Airport, conduct visual flight rules photogrammetry in Hualien and Taitung areas, and land at Taitung Airport after completion.
The aircraft took off at 0726. Approximately 18 minutes later, the flight crew changed from instrument flight rules to visual flight rules. At 0827, the aircraft entered the Hualien County Fenglin, Guangfu, and Wanrong aerial photograph area, maintaining 8,300 to 8,500 feet altitude. It continued climbing to the Jhuosi, Hualien County photo area at 0919.
Communication and Flight Path
Between 0837 and 0843, Taipei Approach informed the flight crew that radar coverage was limited and advised them to maintain visual flight. There were about seven instances of communication blockage between the aircraft and Taipei Approach from 0755 to 0913. Kaohsiung Approach Control contacted the aircraft at 0913:39 but lost contact at 0914:20 after the last communication.
At 0920:55, the aircraft was at a heading of 260 degrees, 31.5 km from Yuli, Taitung in a mountain area, and began a right turn to heading 280 degrees. The last recorded Light Detection and Ranging (LIDAR) data showed the aircraft at coordinates 23°20′25.01″N, 121°01′50.03″E, at an altitude of 9,572 feet, ground speed of about 69 knots, heading 250 degrees, climb rate of 874 ft/min, and pitch of 23.5 degrees.
Search and Discovery
At 0940, Taipei Mission Control Center received Emergency Locator Transmitter signals. Simultaneously, the Japan Coast Guard notified the Rescue Command Center of the same signals. After verification with the Civil Aeronautics Administration, the RCC confirmed the aircraft had lost contact. On September 1, 2012, at 0955, search and rescue aircraft discovered the wreckage at an altitude of about 9,568 feet in a forested area, approximately 20 km southwest of Jhuosi, Hualien County. The three crew members on board were killed, and the aircraft was destroyed.
Probable Cause
After completing the aerial photogrammetry of Morakot No.16 measuring line, the aircraft turned 280 degrees to the right and attempted to climb out of the valley area. During the climb, the aircraft’s pitch remained above 20 degrees for several seconds, likely approaching a stall and activating the stall warning. The aircraft’s performance was insufficient to clear obstacles ahead, and it flew into trees and crashed. When completing the photogrammetry from north to south, the aircraft could not overcome the mountains ahead with its best climb performance. Although a right turn provided a longer climbing distance, the area geography was not suitable for a circling climb or turn to escape the mountainous terrain safely. The crew chose to perform the Morakot photogrammetry after completing work at Wanrong Woods without advance planning due to a backlog in the schedule.