The Taiwan Transportation Safety Board (TTSB) released the final report on the crash of the Coast Guard B-AAA01397 drone during a flight test in Dulan, Taitung on January 17, 2023.

At 0939 on January 17, 2023, an AXH-E230RS drone of the Eastern Branch of the Coast Guard Administration, registration number B-AAA01397, crashed on the beach of Doulan coast, Taitung County while returning from a flight test. There were no casualties.

In accordance with the Transportation Occurrence Investigation Act, and the content of Annex 13 to the Convention on International Civil Aviation, the TTSB, an independent transportation occurrence investigation agency, was responsible for conducting the investigation. The investigation team is composed of members from Civil Aeronautics Administration (CAA), Eastern Branch of the Coast Guard Administration, AVIX Technology Inc. and MiTAC Information Technology Corp.

Based on comprehensive factual information and analyses, the final report presents 3 conclusions along with 2 safety recommendations issued to the relevant organizations. This final report was reviewed and approved by the 64th TTSB Board Meeting on June 14, 2024.

Conclusion:

1. The occurrence was caused by the fracturing of tail rotor pitch links during flight, leading it impossible to control the flight attitude. No other evidence indicates the possible causal factors to the flight control computer nor the human operations.
2. The drone's tail rotor slider assembly may have suffered from poor manufacturing and assembly quality of the old model slider and other components. This issue caused friction and obstruction in the assembly during rotation, resulting in the pitch control yoke deforming and the pitch links fracturing, ultimately leading to the loss of control and consequently, the crash of the drone.
3. Before the occurrence, the manufacturer re-designed the specification of the tail rotor slider due to the production line assembly problems, but failed to evaluate the suitability of old model parts still in use, which posed a risk to flight safety.

Transportation Safety recommendation
Arising from the conclusions of the investigation, the following safety recommendations are issued to relevant organizations.

To AVIX Technology Inc.
Strengthen the quality control of the design, manufacturing and assembly of drones, and evaluate the suitability of old model parts still in use after the design changes.

To Civil Aeronautics Administration, Taiwan
Assure the AVIX Technology Inc., the design and modification of drones in compliance with applicable inspection standards.

Full Final Report in Chinese is available for download at https://www.ttsb.gov.tw

Vivi Yang, Secretariat Office
Tel: +886-2-7727-6217
E-mail: viviy2314@ttsb.gov.tw

Kuo-Chih Chang, Investigator
Aviation Occurrence Investigation Division
Tel: +886-2-7727-6310
E-mail: kcchang@ttsb.gov.tw