What happened
On February 7, 2005, China Airlines flight CI150D, an A300B4-600R with registration B-18579, was en route from Taipei Taoyuan International Airport to Nagoya, Japan. While cruising at 33,000 feet along the M750 airway, the aircraft encountered significant atmospheric disturbances near Iwo Jima.
Flight data recorder (FDR) analysis indicates that the aircraft first encountered light turbulence approximately 20 nautical miles northwest of Iwo Jima at 11:08 UTC. By 11:10:12 UTC, the instability intensified, causing the autopilot to disengage three seconds later. For approximately 28 seconds, the aircraft experienced violent vertical accelerations ranging from +1.744 G to +0.015 G, and lateral accelerations between +0.13G and -0.11G.
The pilot flying reported initial light vibrations followed by a rapid change in airspeed and speed trends, prompting the use of the seatbelt sign. During the period of intense turbulence, some passengers had not yet returned to their seats, and cabin crew were still securing service items. The event resulted in 2 passengers suffering fractures and 4 cabin crew members sustaining minor injuries.
The investigation
The investigation was conducted by the Taiwan Transportation Safety Board (formerly ASC) following a request from Japanese authorities, as the occurrence took place in Japanese airspace. Investigators analyzed FDR data, examined the aircraft's structural integrity following the event, and interviewed the crew.
Post-flight inspections of the aircraft confirmed no structural damage, and all critical systems, including fuel, hydraulic, and oil systems, were found to be operating normally. The investigation also reviewed the airline's weather information acquisition processes and cabin safety procedures.