Piper PA-18A N1927A accident near Charlestown, New Hampshire

Probable cause

The pilot’s failure to see and avoid power lines while maneuvering at low altitude.

NTSB analysis

The pilot of the tailwheel equipped, high-wing airplane stated that he descended over the river and flew a low reconnaissance flight over the water to find a suitable floatplane landing site for the future. A witness, who was located on a boat ramp, recorded the airplane as it flew over the water at an altitude of about 10 to 20 ft. The airplane banked and turned as it followed the contours of the river while on a southern heading before disappearing out of view about a mile away as it made another turn around a bend in the river.

The airplane continued to fly south over the water. According to the pilot, he initiated a climb back toward cruising altitude well before reaching a set of power lines spanning the river. The pilot reported then hearing an “extreme bang” followed by a loss of engine power. His attempts to troubleshoot were unsuccessful, and he reported that he attempted to land on a field adjacent to the river but impacted the power lines as he was turning onto final approach. The power lines were about 30 to 40 feet over the water and spanned the width of the river. They were neither physically marked nor required to be marked, but they were depicted on the sectional area chart for that area.

Postaccident examination of the engine did not reveal any discrepancies that would preclude normal engine operation. While the magnetos were worn down at the block electrodes, they produced spark when tested. A carburetor icing chart was used to determine icing probability, yielding a potential for serious icing at glide power based on the weather conditions at the time. However, the nearest available weather used for this analysis was from an airport 7.5 nautical miles (nm) away, and it is likely that the pilot maintained sufficient power during maneuvering and his climb. Based on this information, no evidence supporting the reported loss of engine power was found during the course of the investigation. Therefore, it is likely that the pilot did not climb sufficiently before reaching of the power lines, which resulted in an in-flight collision with the power lines and impact with the river.

Text from the NTSB. Open the NTSB docket for ERA22LA283 for the full record.