Dehavilland DHC-2 N930TG accident near Ketchikan, Alaska

Probable cause

The pilot's misjudgment of the takeoff distance needed to depart the lake, and his subsequent failure to maintain clearance from the water during a turn to avoid terrain, which resulted in impact with water.

NTSB analysis

The pilot landed the float-equipped airplane at a remote mountain lake as part of a sightseeing tour flight. During the subsequent takeoff, the pilot realized that the airplane was not going to clear trees in the intended direction of departure. The pilot decided to lower the nose and turn 180° to remain over the lake while continuing to climb; however, during the turn, the airplane impacted the water and began to sink. All of the occupants egressed and swam to shore. The operator reported no preimpact mechanical failures or malfunctions with the airframe and engine that would have precluded normal operation of the airplane.

Another airplane of the same make and model as the accident airplane successfully departed the lake shortly after the accident.

Given the lack of mechanical malfunctions with the accident airplane and the fact that the other airplane performed a successful takeoff, it is likely that the accident pilot misjudged the required departure distance and altitude needed to safely depart the lake, then failed to maintain sufficient clearance from the water during the turn to avoid terrain.

Text from the NTSB. Open the NTSB docket for ANC17LA032 for the full record.