On June 1, 2006, a Grumman G-164B (registration N14RY) was involved in an aviation accident near Dighton, KS. Investigators recorded the probable cause as: A fractured rocker arm boss on the number 1 cylinder that left the exhaust valve closed, resulting in a loss of engine power. This summary draws on records from the U.S. National Transportation Safety Board (NTSB) historical archive.
During an aerial application takeoff, the engine lost power shortly after lift-off. The pilot landed toward the departure end, but the aircraft exited the runway into a wheat field, nosed over, and sustained damage. The pilot suffered minor injuries. Examination found a fractured rocker arm boss on the number 1 cylinder.
Accident Overview
An aerial application flight experienced an engine failure shortly after takeoff. The commercial pilot executed a landing on the remaining runway, aiming toward the departure end. However, the aircraft overran the runway and entered a wheat field. The main landing gear tires became embedded in soft, wet soil, causing the aircraft to nose over. This resulted in the engine fracturing and separating from the fuselage, and the vertical stabilizer and rudder were crushed downward. The pilot sustained minor injuries. Visual meteorological conditions prevailed at the time of the accident.
Engine Examination
Post-accident examination of the engine revealed a fracture in the rocker arm boss on the number 1 cylinder. This fracture prevented the exhaust valve from opening, leading to the loss of engine power. The failure of the rocker arm boss was the direct cause of the engine failure during the takeoff phase.
Probable cause
A fractured rocker arm boss on the number 1 cylinder that left the exhaust valve closed, resulting in a loss of engine power.