On May 24, 1987, a Hiller UH-12D (H23) (registration N6408) was involved in an aviation accident near Spartanburg, SC. This summary draws on records from the U.S. National Transportation Safety Board (NTSB) historical archive.
During a local pleasure flight, a passenger reported hearing a loud pop; the pilot stated they were going down, and the main rotor blades slowed before colliding with trees and ground. A post-impact fire consumed the wreckage. Examination found no mechanical malfunction, though the fuel and ignition system was destroyed.
Accident Overview
During a local pleasure flight above the treetops, a passenger reported hearing a loud 'pop' over the sound of the engine. The pilot informed the passenger that they were going down. The passenger then noticed the main rotor blades began to turn slower than usual before the helicopter collided with trees and then the ground. A prolonged post-impact ground fire consumed the wreckage.
Examination
A thorough examination of the flight controls, engine, and transmission assembly did not reveal any evidence of mechanical malfunction. However, the fuel and ignition system was completely destroyed by fire and could not be evaluated.
Pilot Background
Associates of the pilot stated that he usually operated at approximately 200 ft AGL.