On February 4, 1991, a Piper J-3-C (registration N6337H) operated by Pro Aero was involved in an aviation accident near Hamilton, OH. Investigators recorded the probable cause as: Improperly set carburetor float resulting in an overly rich mixture at various power settings. This summary draws on records from the U.S. National Transportation Safety Board (NTSB) historical archive; 1 related events involving the same aircraft type or operator are linked below.
During a checkout flight, a CFI and private pilot performed stalls when the propeller stopped. The aircraft, lacking a starter, could not restart. The pilot landed 30 feet short of a 4000-foot field, collapsing the landing gear. An FAA report noted an improperly set carburetor float causing an overly rich mixture.
Incident Overview
A certified flight instructor (CFI) was conducting a checkout flight with a private pilot when the engine's propeller stopped during stall maneuvers. The aircraft was not equipped with a starter, and attempts to windmill the propeller were unsuccessful.
Landing and Damage
The pilot subsequently attempted to land in a 4000-foot field but touched down approximately 30 feet short of the field's boundary. The impact collapsed the landing gear, according to the Federal Aviation Administration (FAA).
Carburetor Issue
In its report, the FAA noted that the carburetor float was improperly set. This caused an overly rich fuel-air mixture at various power settings. Additionally, black smoke was observed emanating from the exhaust pipes when the engine was between idle and 1400 revolutions per minute (RPM).
Probable cause
Improperly set carburetor float resulting in an overly rich mixture at various power settings.