Casualties unknown

1987-02-07: Aeronca 7EC (N4715E) — Big Fork, MN

Big Fork, MN, US

On February 7, 1987, an Aeronca 7EC (registration N4715E) was involved in an aviation accident near Big Fork, MN. Investigators recorded the probable cause as: The pilot's failure to maintain adequate clearance during takeoff from a snow-covered lake, resulting in the left aileron striking a fish house. This summary draws on records from the U.S. National Transportation Safety Board (NTSB) historical archive.

Sourcesthe U.S. National Transportation Safety Board (NTSB) historical archivePrimary reportUpdated 1781061362Data APIEditorial standards

After multiple failed takeoffs from a snow-covered lake, the pilot located a plowed area near a fish house. During the subsequent attempt to depart eastward, the left aileron struck the structure before landing safely nearby.

What happened

The pilot had previously made several unsuccessful attempts to initiate takeoff from a snow-covered lake surface. Seeking better traction or clearance, the pilot identified a plowed area that provided access to a fish house located on the ice. The aircraft was taxied into this prepared zone, and the pilot began a takeoff roll directed toward the east.

During the initial rotation phase of the flight, as the aircraft lifted off the ground, the left wing's control surface made contact with the upper portion of the fish house structure. Despite this impact, the pilot maintained control of the aircraft and continued the maneuver. The aircraft landed safely approximately 50 yards beyond the obstacle without sustaining further damage or incident.

The investigation

The physical examination of the aircraft confirmed that the left aileron was damaged due to contact with the fish house during the lift-off phase. No other mechanical anomalies were reported prior to the event. The snow conditions on the lake likely contributed to the initial difficulty in achieving sufficient airspeed for takeoff, prompting the search for an alternative departure point.

Findings

The primary factor leading to the incident was the choice of a departure location that lacked adequate vertical clearance above nearby structures. The pilot's decision to utilize a plowed area near a fish house resulted in insufficient height during rotation. The lack of successful takeoffs from the open lake surface suggests potential issues with snow density or aircraft performance relative to the available runway length on ice.

Safety message

Pilots operating from unprepared surfaces, particularly frozen bodies of water, must ensure that all obstacles along the intended flight path are accounted for. Adequate clearance above structures such as fish houses is critical during the initial climb phase where altitude gain is minimal.

Probable cause

The pilot's failure to maintain adequate clearance during takeoff from a snow-covered lake, resulting in the left aileron striking a fish house.

Investigation report by the U.S. National Transportation Safety Board (NTSB) historical archive. Original record: https://carol.ntsb.gov/event/20001213X30208. This page is a structured re-presentation; facts and quotes are in the National Transportation Safety Board (NTSB), United States.