Sikorsky Aircraft Corp S-76 N36RP accident near Round Mountain, Texas

Probable cause

The flight crew’s failure to properly identify the heliport in dark night conditions, which resulted in the flight crew attempting to land and a subsequent impact with trees and terrain.

NTSB analysis

The purpose of the on-demand night flight in the helicopter was to transport the passenger from a commercial airport to a private heliport on a ranch in a rural area. Due to previous issues with the helicopter’s autopilot system and the possible concern of losing control in instrument meteorological conditions, the captain decided not to perform an instrument flight rules flight to the heliport.

During the flight, an instrument approach was loaded into the helicopter’s flight management system, but it was not activated. Additionally, each pilot had an Apple iPad mounted in the cockpit, that was utilizing ForeFlight with the heliport coordinates loaded into ForeFlight. During the approach to the heliport, the captain contacted the ranch manager via text message on a cellular phone, to ensure the heliport floodlight system was activated. The first officer activated the heliport ground lights, which were a green color, via a radio frequency. Both pilots acknowledged observing green lights in their sight. The captain reported that he “cross-checked” the map display with the outside visual references to confirm alignment with the heliport, which he thought had matched. The first officer extended the landing gear, he completed the before landing checklist, and he then transitioned to viewing outside of the helicopter to try and visually acquire the heliport.

The captain delayed turning on the landing lights until closer to the heliport to avoid glare from moisture and haze reflecting in the light beams. The captain began maneuvering the helicopter for landing. Within seconds, the captain lost outside visual references, and he transitioned to instruments. The first officer looked inside the cockpit and observed the radar altimeter indicated 20 ft. Before the first officer could verbally call out to execute a go around, the helicopter terrain awareness and warning system activated an alert, and the helicopter impacted trees and terrain.

The helicopter sustained substantial damage to the fuselage, the main rotor system, the tail boom, the empennage, and the tail rotor system. The captain reported there were no preimpact mechanical malfunctions or failures with the airframe or the two turboshaft engines that would have precluded normal operation.

A review of meteorological data at the time of the accident showed dark night conditions were present for the accident site.

It is likely the flight crew failed to properly identify the heliport in dark night conditions, which resulted in the flight crew attempting to land at the incorrect location. It is also likely the flight crew failed to properly utilize navigation information and visual cues to verify the location of the heliport.

Text from the NTSB. Open the NTSB docket for CEN25LA356 for the full record.