On November 4, 1984, a Bell 47D1 (registration N93067) operated by Patrick Q Perez was involved in an aviation accident near Terlingua, TX. Investigators recorded the probable cause as: Engine power loss due to water in the fuel, which necessitated an autorotative landing that resulted in main rotor blades striking the tail boom. This summary draws on records from the U.S. National Transportation Safety Board (NTSB) historical archive.
A helicopter experienced engine power loss shortly after takeoff during a sightseeing flight. The pilot executed an autorotative landing, resulting in main rotor blades striking the tail boom due to water contamination in the fuel system.
What happened
Shortly after takeoff on a sightseeing flight, the helicopter's engine lost power while the aircraft was positioned over rough terrain at approximately 200 feet above ground level. The pilot initiated an autorotative landing procedure to manage the sudden loss of propulsion. During the descent and subsequent touchdown, the helicopter rocked forward significantly. This forward motion caused the main rotor blades to strike the tail boom structure.
The investigation
The pilot reported that the power loss was attributable to a small amount of water present in the fuel supply. No further mechanical examination details were provided in the source text.
Findings
The sequence of events indicates that fuel contamination led to immediate engine failure at low altitude. The resulting autorotation maneuver, while necessary for survival, resulted in structural damage due to the forward rocking motion of the airframe upon landing.
Probable cause
Engine power loss due to water in the fuel, which necessitated an autorotative landing that resulted in main rotor blades striking the tail boom.