Casualties unknown

1991-09-26: Bell 47G-5A (N59424) — Tiller Helicopter Service, Inc — Pearsall, TX

Pearsall, TX, US

On September 26, 1991, a Bell 47G-5A (registration N59424) operated by Tiller Helicopter Service, Inc was involved in an aviation accident near Pearsall, TX. Investigators recorded the probable cause as: The pilot's failure to see and avoid power lines during the initial climb after takeoff. This summary draws on records from the U.S. National Transportation Safety Board (NTSB) historical archive.

Sourcesthe U.S. National Transportation Safety Board (NTSB) historical archivePrimary reportUpdated 1781061362Data APIEditorial standards

A helicopter conducting a power line patrol flight struck overhead wires during initial climb after refueling from a truck, resulting in a destructive post-crash fire.

What happened

The pilot was operating a helicopter on a routine power line patrol mission. Prior to the final leg of the day's operations, the pilot landed in an area adjacent to a road to refuel the aircraft using fuel transferred from an operator's truck. Following this ground stop, the pilot initiated takeoff for the next segment of the flight.

During the initial climb phase after departure, the helicopter's skids made contact with power lines that were not visible during the preceding approach or takeoff planning. The collision with the wires caused the aircraft to lose control and nose over. The helicopter subsequently impacted the ground at a low altitude. A post-crash fire ensued, which completely destroyed the aircraft.

The investigation

The examination of the wreckage confirmed that the initial point of impact involved the skids striking overhead power lines. The force of the wire strike induced a nosing-over attitude, leading to ground impact and subsequent fire damage that rendered the airframe unrecoverable.

Findings

  • failure to see obstacles during approach and takeoff phases
  • power line contact resulting in loss of control
  • post-crash fire causing total destruction

The pilot's inability to observe the power lines during both the landing approach and the subsequent takeoff climb was a critical factor in the sequence of events. The refueling operation from a truck on the ground did not directly contribute to the mechanical failure but set the context for the final flight segment where visibility limitations played a role.

Safety message

Pilots conducting low-level operations near utility infrastructure must maintain heightened situational awareness. Power lines can be difficult to see, especially during climb or descent phases in varying light conditions. Thorough pre-flight and in-flight visual scanning is essential to avoid wire strikes.

Probable cause

The pilot's failure to see and avoid power lines during the initial climb after takeoff.

Investigation report by the U.S. National Transportation Safety Board (NTSB) historical archive. Original record: https://carol.ntsb.gov/event/20001212X18102. This page is a structured re-presentation; facts and quotes are in the National Transportation Safety Board (NTSB), United States.