On June 17, 1999, a Bell 206B-III (registration N94WF) was involved in an aviation accident near Tinicum, PA. Investigators recorded the probable cause as: The pilot's failure to maintain visual reference with the outside environment while conducting aerial application, which resulted in the helicopter striking the water. This summary draws on records from the U.S. National Transportation Safety Board (NTSB) historical archive.
A pilot conducting aerial application work over the Delaware River lost altitude after looking at a cockpit gauge, causing the helicopter's skids and main rotor to strike the water.
What happened
The incident occurred while the pilot was engaged in aerial application operations over the Delaware River. During the flight, the pilot’s attention was momentarily diverted from the external environment as he looked at a flow gauge located inside the cockpit. This distraction resulted in the helicopter descending to an altitude that was too low for the operation. Consequently, the aircraft's skids made contact with the water surface. Following this initial impact, the main rotor blades also struck the water. The helicopter then came to rest submerged in the river.
The investigation
The pilot provided a statement regarding the sequence of events leading to the accident. He confirmed that his focus was shifted to the internal flow gauge at the time of the incident. This admission indicates that the loss of situational awareness was self-reported by the operator during the post-accident review.
Findings
The primary factor contributing to the accident was the pilot's temporary diversion of attention away from flying the aircraft. By focusing on the flow gauge, the pilot failed to maintain adequate altitude over the water. This lapse in visual scanning led directly to the controlled flight into terrain (water) and subsequent structural damage to the skids and rotor system.
Probable cause
The pilot's failure to maintain visual reference with the outside environment while conducting aerial application, which resulted in the helicopter striking the water.