Dehavilland DHC 2 N115CX accident near Iliamna, Alaska

Probable cause

The pilot’s improper decision to operate the airplane at low altitude and deliberately in close proximity to the boat operators, which resulted in a collision with a boat operator.

NTSB analysis

The commercial pilot was participating in a mission that included another airplane and two boat operators who were moving two open, 18-ft skiffs downriver. The pilot reported that, after the two boat operators departed, he started the float-equipped airplane and departed in the same direction that the boat operators had traveled. He added that he maintained a low altitude and that, after he passed the first boat, he "felt the airplane start to sink" and that, when he pulled back on the yoke to arrest the sink, he felt the back of the float hit something. The airplane had struck one of the boat operators.

GPS data for the flight showed that the airplane did not climb after takeoff but instead remained at very low altitude and followed the river channel for more than 1 mile in the same direction that the boat operators had traveled. The first boat operator reported seeing the airplane pass directly over him about 15 or 20 ft above the water before proceeding toward the other boat operator, dropping down, and then hitting the other boat operator. He described the event as a "buzz job" and said that the pilot had buzzed them before.

Although the pilot reported that the airplane sank unexpectedly after he passed the first boat operator, his chosen low altitude and flightpath placed the airplane in dangerous proximity to the boat operators (which was inconsistent with federal regulations) and allowed no margin to arrest a sink rate and avoid the collision. The other company pilot reported that there was no mission- or airplane performance-related reason for the airplane to be operating at such a low altitude over the river in the area where the collision occurred.

Text from the NTSB. Open the NTSB docket for ANC14LA046 for the full record.