Piper PA 18 N7071B accident near Beluga, Alaska

Probable cause

The pilot’s decision to perform a takeoff with an overweight float-equipped airplane, which resulted in diminished climb performance.

NTSB analysis

The private pilot performed a takeoff in his float-equipped airplane from a small lake with one passenger. The pilot estimated the lake to be 750 ft long, the weight of the airplane at 1,716 lbs, and the wind to be light and variable between 3 and 8 knots. He applied full power with one notch of extended flaps. At 40 mph, he extended the flaps another notch and the airplane lifted off the water, but it was unable to climb. The pilot and passenger stated that they did not observe or hear any abnormal engine indications. According to the pilot, the airplane descended to the ground beyond the lake, and the right float and wing impacted the ground. The airplane sustained substantial damage to the fuselage and right wing.

The night of the accident, the pilot stated that he overloaded the airplane with moose meat and was forced to land after takeoff; he later stated that he did not know what caused the lack of climb performance, but “maybe it was a lack of engine power.” Additionally, he reported that he estimated the meat’s weight without weighing it, but he was confident that, including the load, the airplane’s takeoff weight was within the maximum gross weight limit, which was 1,760 lbs. The investigation was unable to determine the actual takeoff weight of the airplane due to the remote location of the accident and inaccessibility of the evidence.

Postaccident engine examination and an engine test run revealed no anomalies that would have prevented normal operation.

Given the pilot’s initial statement that the airplane was overloaded, his failure to weigh the load, and no evidence of engine anomalies, it is likely that the moose meat weighed more than the pilot estimated and that the airplane was overweight during the takeoff from the small lake.

Text from the NTSB. Open the NTSB docket for ANC19LA054 for the full record.