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Casualties unknown

1996-01-14: Ercoupe (eng & Research Corp.) 415-C (N87424) — Hurlock, MD

Hurlock, MD, US

On January 14, 1996, an Ercoupe (eng & Research Corp.) 415-C (registration N87424) was involved in an aviation accident near Hurlock, MD. Investigators recorded the probable cause as: inadequate inspection by maintenance personnel which failed to detect a fatigue crack, and resulted in an in-flight crankshaft fracture and propeller assembly separation. A related factor was the deep snow encountered during the subsequent forced landing. 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 pilot reported that the propeller separated from the airplane during cruise at 1,500 feet MSL. An emergency landing was made in a snow-covered field, where the nose wheel collapsed upon touchdown in 18-inch deep snow. Postaccident examination revealed a spiral crack in the crankshaft filled with an iron nitride white layer.

Incident Overview

The pilot stated that while the airplane was in cruise flight at an altitude of 1,500 feet MSL, the propeller separated from the airplane. An emergency landing was subsequently performed in a snow-covered field. Upon touchdown in 18-inch deep snow, the nose wheel collapsed.

Examination of Separated Components

The separated propeller assembly, along with the attached forward portion of the crankshaft flange, were recovered and examined at the NTSB laboratory. Postaccident inspection of the crankshaft revealed a spiral crack that intersected the fracture at the bottom corner of a keyway. Further examination showed that the cracks were filled with an iron nitride white layer.

Maintenance History

Maintenance records indicated that the main journals and pins of the crankshaft were ground, nitrided, inspected, and returned for service in October 1994.

Structural failure

More accident analyses

Investigation report by the U.S. National Transportation Safety Board (NTSB) historical archive. Original record: https://carol.ntsb.gov/event/20001208X05102. This page is a structured re-presentation; facts and quotes are in the National Transportation Safety Board (NTSB), United States.