What happened
On August 30, 2012, a BN-2B-26 aircraft, registration B-68801, operated by Dapeng Airlines, crashed in the mountains of Hualien County, Taiwan. The aircraft was engaged in an aerial survey mission involving LiDAR equipment, carrying a crew of four, including a pilot, co-pilot, and two survey technicians.
The flight departed from Songshan Airport at approximately 07:26. After completing survey tasks in the Wanrong Forest area, the aircraft proceeded toward the Monarc disaster area for supplemental survey work. At approximately 09:22, the aircraft was recorded at an altitude of 9,572 feet, climbing at a rate of 874 feet per minute. Shortly thereafter, the aircraft disappeared from radar and communication. An Emergency Locator Transmitter (ELT) signal was detected at 09:40, and the wreckage was eventually located on September 1, 2012, in a forested area near Zhuoxi Township.
The investigation
The Taiwan Transportation Safety Board (TTSB) investigation examined the flight logs, LiDAR sensor data, and maintenance records. The investigation focused on the aircraft's flight path through the valley, the terrain encountered, and the operational procedures used for mission planning. Investigators also reviewed the integration of survey maps and the training and oversight protocols of the operator.
Findings
- The aircraft attempted to turn right to a heading of approximately 280 degrees to climb out of a valley. During this maneuver, the aircraft maintained a high pitch angle of over 20 degrees for several seconds, likely approaching a stall condition. The aircraft's performance was insufficient to clear the terrain, leading to a collision with trees.
- The flight path chosen after completing the previous survey line was inherently unsafe, as the terrain to the north and south of the flight path featured mountains that could not be cleared even with optimal climbing performance.
- The crew likely proceeded to an unplanned survey area because the previous mission had been delayed, and weather conditions appeared favorable.
- There were significant deficiencies in mission planning, including the inability to effectively overlay survey maps with topographic contour maps, which prevented the crew from accurately assessing terrain hazards.
- Organizational safety gaps were identified within the operator, including inadequate training for survey technicians regarding aircraft performance and weather, and insufficient oversight of pilot route training and competency checks.