What happened
On July 26, 2011, a privately owned Extra EA300/200, registration JA22DB, departed from the Fujigawa glider strip for a flight test intended to prepare for an upcoming airworthiness inspection. The pilot, flying solo from the rear seat, was performing a routine transponder check. Shortly after takeoff, the aircraft's trajectory was tracked by the Hamamatsu Base radar, which recorded the plane performing a left turn over the Okitsu River estuary.
During the flight, the pilot attempted to communicate with a radar controller to verify the transponder, but the radio transmissions became increasingly interrupted by static. Radar data indicated that the aircraft's altitude dropped sharply from 5,000 feet to 4,600 feet in just eight seconds, followed by a total loss of radar contact. Later that day, search operations recovered various pieces of aircraft debris from the waters of northern Suruga Bay, located between the Fuji and Okitsu River estuaries. The pilot was not found.
The investigation
The JTSB investigation focused on the aircraft's flight path, the prevailing meteorological conditions, and the aircraft's equipment. Investigators examined radar logs from the Japan Air Self-Defense Force, which showed a significant rate of descent just before the aircraft disappeared from radar. The investigation also reviewed the aircraft's instrumentation, noting that the rear cockpit was not equipped with an attitude indicator.
Meteorological data revealed that the region was experiencing unstable atmospheric conditions, with a warm, moist air mass moving into the area. This resulted in heavy thunderstorms and reduced visibility. While debris was recovered, the lack of an Emergency Locator Transmitter (ELT) and the limited amount of wreckage made it difficult to pinpoint the exact impact location or determine if midair disintegration had occurred.
Findings
- The aircraft was operating under Visual Flight Rules (VFR) but lacked an attitude indicator, an instrument essential for maintaining orientation in low-visibility environments.
- The aircraft encountered deteriorating weather, including heavy precipitation and clouds, which likely obscured the horizon.
- The pilot likely experienced spatial disorientation after losing visual references due to the weather.
- The sudden descent could have been a voluntary maneuver to reach the sea surface for better visibility, or an involuntary result of losing control while flying in clouds.
- While a lightning strike or mechanical failure cannot be ruled out, the primary contributing factor was the loss of visual cues in adverse weather.