What happened
The pilot operated a seaplane that had previously completed a taxi along the shoreline, followed by a takeoff and landing sequence. During this initial flight phase, the left pontoon became submerged with water, rendering the aircraft unable to perform a second takeoff from the intended location. To address the issue, the pilot maneuvered the aircraft to a nearby public boat dock where he drained the accumulated water from the pontoon.
Following the drainage procedure, an approaching thunderstorm prompted the pilot to alter his departure plan. He elected to execute a downwind takeoff to expedite departure and avoid potential weather hazards. During the acceleration phase of this takeoff run, the aircraft failed to achieve sufficient lift or gain altitude as expected. Consequently, the seaplane departed the water surface prematurely and collided with trees located near the end of the available runway area.
The investigation
The factual narrative indicates that the primary mechanical impediment was the weight and drag caused by water trapped in the left pontoon. This condition prevented the necessary thrust-to-weight ratio for a safe departure from the initial site. The subsequent decision to utilize a downwind takeoff profile, while intended to mitigate weather risks, likely contributed to the reduced performance margin during the critical ground roll phase.
Findings
The accident resulted from a combination of operational factors. The initial failure was due to the submerged pontoon preventing takeoff. The final collision occurred because the aircraft could not gain altitude during the takeoff run, leading to an impact with terrain obstacles (trees). The pilot's choice to perform a downwind departure in response to weather may have exacerbated performance limitations.