What happened
On April 16, 2006, at approximately 18:15 local time, a Maule M-7-235B amphibious aircraft, registration I-SEAP, was involved in a capsizing incident at the Como waterside (idroscalo) in Italy. The aircraft was performing a taxiing phase for a scheduled 45-minute sightseeing flight for a family of tourists.
While taxiing at low speed toward the takeoff area, the pilot performed an engine power check. During this procedure, the aircraft experienced significant longitudinal oscillations. The pilot of a nearby aircraft, flying a Saab, observed the rear of the I-SEAP left float lifting out of the water and alerted the pilot of the Maule. Shortly after, the Maule M-7-235B pitched forward, causing the cabin to submerge and the aircraft to capsize. The pilot and three passengers were able to exit the submerged cabin and were rescued by a local rescue boat without injuries.
The investigation
The ANSV investigation focused on the aircraft's weight, balance, and the pilot's operational procedures. Investigators examined the aircraft's technical configuration, noting it had been converted to an amphibious configuration with retractable floats. The investigation also reviewed the pilot's flight experience, noting he had very limited recent experience on this specific type, with only about six hours of flight time on the Maule M-7-235B and his last flight on the model occurring seven months prior.
Technical analysis of the load revealed that the aircraft was significantly overweight. The total mass exceeded the maximum takeoff mass by more than 111 kg. Furthermore, the load was unbalanced, with weight distributed heavily toward the right side due to passenger positioning and uneven fuel levels in the wing tanks.
Findings
- The primary cause of the accident was the forward capsizing of the aircraft during the engine test.
- The aircraft was operating with an excessive payload, exceeding the maximum takeoff mass by over 110 kg.
- The load distribution was unbalanced, with a heavy concentration of weight on the right side of the aircraft.
- Sudden power changes during the engine test, combined with the high drag from the deeply submerged floats and a light tailwind, induced large pitching oscillations.
- These oscillations caused the propeller to strike the water surface; the resulting sudden increase in drag from the water contact pulled the nose downward, leading to the capsize.
- The pilot failed to perform a proper safety briefing for the passengers and did not accurately calculate the aircraft's total mass.