On June 22, 1996, a Beech 23 (registration N2397J) was involved in an aviation accident near Fulton, MO. Investigators recorded the probable cause as: the inadequate intake valve springs on the #1 cylinder. This summary draws on records from the U.S. National Transportation Safety Board (NTSB) historical archive.
Witnesses observed abnormal black smoke after takeoff. The aircraft descended through trees and power lines. Postaccident inspection found compression loss in the #1 cylinder, darker manifold areas, and out-of-tolerance valve springs.
Accident Overview
Following takeoff, witnesses reported an abnormal amount of black smoke trailing from the aircraft. The airplane subsequently descended, impacting trees and power lines along its path.
Postaccident Investigation
During the postaccident examination, the engine's #1 cylinder was found to have no compression when checked. After manually prying back the intake valve of the #1 cylinder, compression was restored when the propeller was rotated. The intake and exhaust manifold areas of the #1 cylinder appeared darker in color compared to the other cylinders. Additionally, the valve springs in the #1 cylinder were found to be outside the tolerances specified by the manufacturer.