On May 25, 2002, China Airlines flight CI611 crashed in the waters of Penghu. The China Airlines crash was the first large-scale air disaster at sea in China, with 225 victims. In this operation, our working group first used side-scan sonar to conduct a large-scale scanning of aircraft debris, and R/V OR1, 2 and the Navy provided approximate locations of debris. And use the multi-sound beam sounding system to scan and carefully locate, and its positioning can be accurate to about 3-10 meters. And R/V OR3 anchors (double anchors) at the exact position of the remnant according to the direction of the current and the wind. Then put down the underwater unmanned remote control submersible to search for aircraft debris on the seabed, and the range of activities of the underwater unmanned remote control submersible is usually controlled within 10-20 meters. 

        The multibeam sounding system supported this time carefully scanned hundreds of kilometers and found 4 large aircraft remnants. (1. About 2-3 meters tall and narrow. 2. A T-shaped target about 10 meters high and 10 meters wide. 3. A large target with a length of about 40 meters, a width of about 20 meters, and a height of about 4-5 meters. 4. A target about 8 meters long and 4-6 meters high, surrounded by scattered debris.) After careful positioning, the precise location will be given to the Ministry of Communications, the Aviation Safety Committee and the Asia-Pacific company to facilitate subsequent salvage work. The results are shown in the figure.

        At the same time, the unmanned underwater remote control vehicle (ROV) was also used to find aircraft debris near the scene of the oil and gas phenomenon during the first voyage (2002/5/31~2002/6/4), and a piece of debris was picked up. The aircraft remnant is about 10cm x 10cm and has a fuel pipe buckle, and it was quickly handed over to the Air Safety Committee for identification. In the second voyage (2002/6/8~2002/6/14), through the results and accurate positioning of the multibeam sounding system and using R/V OR3 to lock the position of the target with double anchors, successfully captured the image of the tail. Also convert the captured video to a digital disc. This time also confirmed the practicality and importance of the multi-beam sounding system in underwater search.

Stereoscopic image of the wings of China Airlines flight CI611 in Penghu sea area measured by multibeam sounding system (upper left) 40-meter cockpit image (bottom left) tail image (bottom right)