Cessna 172XP N758HP accident near St. Cloud, Minnesota

Probable cause

The pilot's failure to maintain the proper airspeed and angle-of-attack after a partial loss of engine power on takeoff, which resulted in a stall and the subsequent impact with water. Contributing to the accident was the partial loss of engine power due to the No. 3 cylinder not producing compression for reasons that could not be determined based on the available evidence.

NTSB analysis

The pilot reported that everything was normal when he conducted a preflight inspection and engine run-up of the single-engine, float-equipped airplane before takeoff from a lake. The airplane departed, and, as it began to climb, the engine started to lose power. The airplane then stalled, the left wing dropped and struck the water, and the airplane flipped inverted and eventually sank.

Postaccident examination of the engine revealed that, when the propeller was rotated manually, all of the engine cylinders, except for the No. 3 cylinder, produced compression. The intake valve, exhaust valve, and rocker arm moved when the propeller was rotated. No further examination of the engine was conducted, and the reason for the No. 3 cylinder's failure to produce compression could not be determined. It is likely that, as the engine began to lose power, the pilot did not maintain the proper airspeed or angle-of-attack, which led to a stall and the subsequent impact with water.

Text from the NTSB. Open the NTSB docket for CEN14LA320 for the full record.