On February 2, 1983, a Cessna A188B (registration N4784Q) operated by Pacific Air Research, Inc. was involved in an aviation accident near Medford, OR. Investigators recorded the probable cause as: The pilot's inadequate visual scanning of the orchard boundaries, which resulted in the aircraft striking a taller boundary tree during aerial application operations. 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.
An aircraft involved in aerial application operations struck a boundary tree while spraying an orchard, resulting in significant damage to the oil cooler and forcing an off-airport landing.
What happened
The aircraft was engaged in aerial application operations when it collided with a tree. According to the pilot's account, the operational area was an orchard characterized by specific boundary features: a powerline at one end and a row of leafless trees at the opposite end. During the spraying process, the pilot overlooked one of the taller boundary trees located at the edge of the orchard. The aircraft struck this tree, which resulted in immediate mechanical damage.
The investigation
The collision with the tree punched a hole in the oil cooler. This structural failure necessitated an immediate change in flight operations. Due to the compromised mechanical integrity of the engine cooling system, the pilot was forced to execute an off-airport landing to ensure safety.
Findings
The primary factor contributing to the incident was the pilot's failure to account for all boundary obstacles during the low-level spraying operation. Specifically, the taller boundary tree was not identified or avoided in time. The resulting damage to critical engine components directly led to the emergency landing situation.
Probable cause
The pilot's inadequate visual scanning of the orchard boundaries, which resulted in the aircraft striking a taller boundary tree during aerial application operations.