Accident with an amphibious aircraft (Twin Bee) at Lake Siljan

Summary

A seaplane instructor and two students were at Lake Siljan to carry out seaplane training within the framework of an Austrian ATO. However, the instructor had not yet completed his annual refresher training for the flight school and, pending doing so, conducted a number of flights with the students as a private flight.

On July 18, one of the students was planned to make his first flight on sea with the instructor. The intention was to perform repeated take-offs and landings on Lake Siljan together with the instructor. The session had a high degree of diffi-culty and was likely designed based on the student having previous experience on the aircraft type.

The weather observation indicated good visibility with high cumulus clouds and moderate variable winds from the southwest. The flight took off from Siljansnäs Airport. After completing several landings, the aircraft turned to an east-north-easterly direction over Sollerön island for another landing. In connection with the landing attempt, the aircraft tipped forward and flipped around. The instruc-tor and the student where fatally injured.

The aircraft is believed to have been configured for landing on water with the landing gear retracted before the accident. No technical fault with the aircraft that may have affected the accident has been identified.

Causes/Contributing Factors

The accident was caused by the flight being planned and executed in such a way that the degree of difficulty became too high in relation to the instructor's recency on type and the student's seaplane experience.

Before the landing, no reconnaissance was performed, which has contributed to the landing being carried out at high speed, in tailwind and probable rough sea in relation to the aircraft's limitations.

Safety Recommendations

EASA is recommended to:

• produce safety-promoting materials for seaplane operations and inform relevant actors. (SHK:2023:12 R1)