Accident Overview
On April 15, 2017, at approximately 11:23 Japan Standard Time, a Cessna T206H amphibian aircraft (registration JA007P) sustained substantial damage during a takeoff run from water at Lake Shinji, located in Tamayu Town, Matsue City, Shimane Prefecture, Japan. The aircraft was operated by a private pilot and carried one passenger. No injuries were reported.
Flight History
The aircraft was scheduled for a familiarization flight from Shinji Lake to Tottori Airport. The pilot, a 71-year-old male holding a private pilot certificate with single-engine land and sea ratings, performed a pre-flight inspection around 10:00, confirming full fuel and no abnormalities. The pilot observed westerly winds and whitecaps on the north side of a cape (Yumachi-Hana) but judged the smoother water along the cape suitable for takeoff, expecting to become airborne within about 300 m. He did not consult the Pilot’s Operating Handbook for amphibian performance. At around 11:00, the passenger noted increasing wind. The pilot started the engine at the pier, taxied southeast to a downwind point, performed the takeoff checklist, and at 11:22 reported to Izumo Radio his imminent departure. He then commenced a takeoff run with flaps at 20°, heading northwest along the lakeshore east of the cape. During the run, the pilot felt normal engine and aircraft behavior but noted slower acceleration as the aircraft approached rough water with whitecaps. The aircraft reached the step and began to bounce; as the pilot anticipated liftoff, the aircraft collided with a large wave, pitched forward, and the front of the right float struck the propeller, causing the engine to stop. The collision occurred about 100 m offshore near a hotel east of Yumachi-Hana. At 11:23, the pilot reported aborting the takeoff due to high waves and canceled the flight plan. A motorboat witnessed the accident and attempted to tow the aircraft but failed due to strong wind. The aircraft drifted downwind, the passenger transferred to a fireboat, and the aircraft sank after the float separated while drifting. The pilot later stated that he had filled fuel to reach Prefectural Nagoya Airfield, making the aircraft heavier than usual, which increased the takeoff run distance and caused entry into rough water.
Aircraft and Pilot Information
The aircraft was a Cessna T206H amphibian (serial number T20608528, manufactured April 6, 2005) with an airworthiness certificate valid to March 2018. Total flight time was 1,177 hours 11 minutes. At the time of the accident, the estimated weight was 3,782 lb (below maximum takeoff weight of 3,972 lb), and the center of gravity was within limits. The floats were approximately 7 m long and 0.8 m high. The pilot had a total flight time of 1,209 hours 55 minutes, including 1,076 hours on the type, and a valid medical certificate.
Damage
The aircraft sustained substantial damage: the propeller was deformed; the right side bottom of the nose and the right bottom of the engine firewall were deformed; the float separated from the aircraft with outer skin breakage; and the left bottom of the fuselage outer skin was deformed.
Weather Conditions
According to the Matsue Meteorological Office, weather was clear with a temperature of 21°C. Winds were westerly: at 10:00, average 8 kt, maximum gust 16 kt; at 11:00, average 14 kt, maximum gust 28 kt; at 11:20, wind direction west, average 18 kt, maximum gust 30 kt. Whitecaps were observed on the north side of the cape.
Performance and Analysis
The Japan Transport Safety Board analyzed that based on the Pilot’s Operating Handbook, the estimated takeoff run distance under conditions similar to the accident (flap 20°, weight 3,792 lb, 16 kt headwind, 20°C, rippled water) was 502 m, and the total distance to clear a 50 ft obstacle was 812 m. The board considered that meteorological conditions and pilot decisions were involved in the accident, while equipment was not. The analysis indicated that the aircraft entered a rough water area with high waves and collided with a wave during takeoff.