Casualties unknown

1982-04-09: Aeronca 11AC (N85940) — J Mohrmann — Beach Lake, PA

Beach Lake, PA, US

On April 9, 1982, an Aeronca 11AC (registration N85940) operated by J Mohrmann was involved in an aviation accident near Beach Lake, PA. Investigators recorded the probable cause as: The pilot's failure to maintain adequate airspeed during takeoff due to deep snow conditions, which resulted in a tailstrike and separation of the empennage. 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

A ski-equipped aircraft failed to accelerate in deep snow during takeoff, resulting in a tailstrike against a stone wall and separation of the empennage just before becoming airborne.

What happened

The pilot initiated a takeoff roll on a short runway measuring approximately 900 feet. The surface conditions were mixed, with snow covering most of the strip but patches of grass visible in several areas. As the aircraft accelerated, it crossed over a section where the grass was exposed; the pilot noted that the deceleration effect from this area was minimal. However, immediately following this patch, the aircraft entered a zone of deeper, undisturbed snow.

In this deeper snow, the aircraft lost its ability to accelerate effectively. The runway ended with a downward slope leading toward the remnants of a partially removed stone wall. Just before reaching the edge of the slope, the pilot attempted to rotate the aircraft. During this maneuver, the tailwheel dragged through the deep snow, causing the tail section to strike the stone wall. Although the aircraft briefly became airborne, it settled rapidly. The impact caused the empennage to separate from the fuselage. The airframe then continued forward through nearby bushes and a swampy area before coming to a final rest.

Findings

The primary factor in this accident was the aircraft's inability to achieve sufficient speed due to high drag from deep, untracked snow. This lack of acceleration prevented the pilot from maintaining control authority and safe climb performance after rotation. The subsequent tailstrike against the stone wall resulted in structural failure of the empennage.

Probable cause

The pilot's failure to maintain adequate airspeed during takeoff due to deep snow conditions, which resulted in a tailstrike and separation of the empennage.

Investigation report by the U.S. National Transportation Safety Board (NTSB) historical archive. Original record: https://carol.ntsb.gov/event/20020917X02536. This page is a structured re-presentation; facts and quotes are in the National Transportation Safety Board (NTSB), United States.