What happened
A flight involving an amphibious-float-equipped airplane began with a departure from a paved runway, intended for a 40-nautical mile trip ending with a water landing on a lake. Following takeoff, the pilot neglected to retract the landing gear. During the transit, the aircraft encountered turbulent air, which triggered frequent alerts from the landing gear advisory system. This system is designed to notify the pilot of the gear's position whenever airspeed drops below a specific threshold, ensuring the gear is up for water operations or down for runway operations.
To avoid the repetitive notifications, the pilot deactivated the system by pulling the circuit breaker. Although there was an intention to restore the system during the descent, this step was not completed. As the aircraft approached the destination, the pilot established a descent rate of 150 to 200 feet per minute to facilitate a landing on the glassy water. Because the landing gear remained in the extended position, the aircraft struck the water and immediately nosed over. The plane eventually came to rest floating upside down, supported by its floats.
Findings
Investigation into the event revealed that the pilot had been on duty for nineteen consecutive days, including both flight and office responsibilities, and noted that this lack of rest was a contributing factor. Additionally, a lack of checklist discipline was identified; while the pilot had utilized written checklists during two previous flights that day, he did not use one for the flight involving the accident. The landing gear remaining in the down position was the primary factor leading to the impact and subsequent inversion.