Accident Overview
On August 6, 2023, at about 0107 central daylight time, a Bell 206 L-3 helicopter, registration N288AE, sustained substantial damage when it struck a wire fence during landing near Carthage, Illinois. The helicopter was operated as a Title 14 Code of Federal Regulations Part 135 air ambulance flight. The pilot, flight nurse, and flight medic were not injured.
Flight Details
The crew—pilot in the front right seat, flight nurse in the rear left, and flight medic in the rear right—were dispatched to pick up a patient from a remote area. The pilot completed a flight risk assessment just before the flight, scoring low risk, and accepted the flight. The operator’s operations control specialist reviewed and acknowledged the assessment.
The helicopter departed from Southeast Iowa Regional Medical Center, Fort Madison, Iowa, at 0051. En route, the aircrew received a landing zone (LZ) brief from the fire department indicating the LZ was an east-west dirt and gravel road with no wires; a wire fence was on the south side, corn fields on both sides. Night visual meteorological conditions prevailed, and marking lights were placed on the LZ. All external lights were on during approach and landing.
Approach and Landing
Upon approach, the pilot and flight nurse transitioned to night vision goggles (NVGs); the flight medic remained unaided. The pilot used an NVG-compatible searchlight to scan the area. The helicopter approached from the northwest at about 700 ft above ground level, performing a high reconnaissance in a left orbit. It then approached from north to south, perpendicular to the road, conducting a low reconnaissance. The flight nurse observed the fence on the south side but thought it was farther away than it was.
The pilot maneuvered to a hover about 10 ft over the road; the crew identified the fence and ditches on both sides. The pilot initiated a right-pedal turn, planning to land with the cabin door facing the accident scene for patient loading. The helicopter's heading was 310° when the pilot began descent toward the road. As the helicopter touched down, the pilot heard a “pop” and felt feedback in the tail rotor pedals. The tail rotor system had struck the wire fence. The pilot lowered the collective and performed an emergency shutdown. The helicopter came to rest upright on a heading of about 360°, perpendicular to the road. The crew egressed without incident. Substantial damage occurred to the vertical stabilizer, tail boom, tail rotor driveshaft, and two tail rotor blades.
Environmental and Operational Factors
At the accident time, the moon was at a relative angle of 25° above the horizon, azimuth 106°, with 73% illumination. The operator’s risk assessment program did not include moon altitude and brightness, but that data was captured on the crew briefing form. The operator reported no preimpact mechanical malfunctions.
The operator’s Part 135 NVG training program included moon angle, distance estimation, and depth perception, but not shadows, construction, terrain density, or vegetation. After the accident, at the suggestion of the NTSB investigator-in-charge, the operator updated the program to include these topics.
The FAA does not provide public reference material for NVG operations on topics like operating characteristics, terrain interpretation, or operational considerations.