On December 7, 2011 at 1630 Pacific Standard Time, a Eurocopter AS350-B2, registration N37SH, operated by Sundance Helicopters as flight Landmark 57, crashed in mountainous terrain approximately 14 miles east of Las Vegas, Nevada. The 14 CFR Part 135 flight was a tourist sightseeing flight, which departed from Las Vegas McCarren International Airport (LAS), Las Vegas, NV, intending to fly to the Hoover Dam area and return to LAS, operating under visual flight rules. The helicopter impacted in a narrow ravine in mountainous terrain between the city of Henderson and Lake Mead. The pilot and four passengers were fatally injured, and the helicopter was substantially damaged by impact forces and post-crash fire. Weather was reported as clear with good visibility and dusk light conditions.

Radar data obtained from the FAA show that the helicopter departed LAS and followed a normal route of flight easterly out of the LAS airport traffic area, then turned to the southeast toward Hoover Dam. Tour routings are standardized for all the area tour operators. The helicopter was level at 3,500 feet mean sea level (MSL) at approximately 120 knots. About one minute prior to the accident, the radar indicated the helicopter climbed to 4,100 feet MSL and turned about 90 degrees to the left. The left turn and climb are not part of the normal route. Radar then indicated the helicopter descended to 3,300 feet MSL and tracked a northeasterly course for about 20 seconds, until entering a left turn then a descent. The last radar target received was about 1/8 miles from the accident site.