On January 26, 2000, a Hiller UH-12E (registration N68024) was involved in an aviation accident near Five Points, CA. Investigators recorded the probable cause as: The pilot's failure to maintain clearance from a telephone line while maneuvering at low altitude, which resulted in the tail rotor striking the line and causing a loss of control. This summary draws on records from the U.S. National Transportation Safety Board (NTSB) historical archive.
A helicopter pilot lost control after the tail rotor struck a telephone line suspended 25 to 30 feet above the ground while maneuvering beneath it during an agricultural spraying flight.
What happened
The pilot was conducting an agricultural operation, specifically intending to spray a nearby field. For the second time, the helicopter was launched from a loading truck rather than a conventional runway or pad. During the flight phase en route to the target area, the aircraft passed over a road.
While navigating this low-altitude environment, the pilot maneuvered beneath a telephone line. The line was suspended at a height between 25 and 30 feet above the ground. The helicopter's tail rotor made contact with the wire. This impact caused an immediate loss of control. The aircraft began to spin around uncontrollably before impacting the ground.
The investigation
The examination focused on the mechanical interaction between the aircraft and the obstruction. Evidence confirmed that the tail rotor struck the telephone line. This physical contact was the direct cause of the loss of directional control.
Probable cause
The pilot's failure to maintain clearance from a telephone line while maneuvering at low altitude, which resulted in the tail rotor striking the line and causing a loss of control.