On September 14, 1992, a Piper PA-25-235 (registration N6953Z) operated by Zach, Herbert was involved in an aviation accident near Powellsville, NC. Investigators recorded the probable cause as: The failure of the number one exhaust valve during the spraying run. This summary draws on records from the U.S. National Transportation Safety Board (NTSB) historical archive.
An agricultural aircraft lost engine power during a spraying maneuver. The pilot attempted a forced landing on a short field but ground looped to avoid traffic on an adjacent road.
What happened
The incident occurred while the pilot was conducting an agricultural spraying operation. During one of the spraying runs, the engine suddenly lost power. Facing an immediate loss of altitude and thrust, the pilot initiated emergency procedures for a forced landing. The available terrain consisted of a short field situated near a public road with active automotive traffic. To prevent a collision with vehicles on the roadway, the pilot steered the aircraft sharply to avoid impact. This evasive maneuver resulted in the airplane ground looping upon touchdown.
The investigation
Following the accident, investigators examined the engine to determine the cause of the power loss. The inspection revealed that the number one exhaust valve had failed. However, the examination did not provide sufficient evidence to determine the specific mode or root cause of this valve failure.
Probable cause
The failure of the number one exhaust valve during the spraying run.