WPR25LA038

The crew of the Part 135 sightseeing flight was returning from a tour when they encountered strong, gusting crosswinds during the landing approach at velocities approaching the airplane’s maximum demonstrated crosswind component (a value which the airplane’s flight manual stated is not considered limiting). The crew elected to continue the approach and land on the airport’s longest and widest runway. The captain, who was the pilot flying, configured the airplane with reduced flaps in accordance with the manufacturer’s crosswind landing recommendations. Both pilots stated that the approach and touchdown were stable and on the centerline; however, shortly after touchdown, a gust or shift in wind direction caused the airplane to veer left. Despite the captain’s corrective control inputs, the airplane departed the runway and struck a runway distance marker, resulting in substantial structural damage. Examination revealed no mechanical anomalies with the flight controls or brakes; neither the crew nor passengers were injured. Review of recorded weather information indicated that the wind conditions encountered during landing were slightly higher than forecast and higher than that reported during departure. Weather at nearby airports showed even higher wind velocities, which would have resulted in comparable or greater crosswind components for their runways. Given that all nearby airports were affected by similar conditions, a diversion was unlikely to provide improved landing conditions.

On November 15, 2024, about 0903 Pacific standard time, a De Havilland DHC-6-300 airplane, N241SA, was substantially damaged when it was involved in an accident near Boulder City, Nevada. The two pilots and 14 passengers were uninjured. The airplane was operated as a Title 14 Code of Federal Regulations Part 135 revenue sightseeing flight. The flight was returning from a tour of the Grand Canyon, after departing from its base of Boulder City Municipal Airport (BVU), about 0800. The crew checked the weather conditions during the initial stages of the landing approach into BVU and noted that the wind had increased since takeoff, and was now out of the southwest gusting to about 27 kts. As they got closer to the airport, they rechecked wind and communicated with the operator, who repeated the weather and stated that all runways were exhibiting crosswinds. The crew then decided to land on runway 27 because it was the longest and widest. The captain was the pilot flying during the landing. The crew decided to perform the landing with 10° flaps due to the strong wind, and they both reported that the approach was stable and the airplane touched down smoothly and on the runway centerline. The captain stated that, shortly after touchdown, the wind changed and the airplane started veering to the left. He countered with right rudder and left aileron, but after the airplane straightened out he felt the left wing lift. He then applied more left aileron control and the airplane departed the runway to the left. The airplane impacted the 3,000 ft runway remaining sign about 1,750 ft from the landing threshold. The captain moved the power levers to reverse, applied brakes, and the airplane came to rest short of a series of drainage ditches. The captain was able to taxi the airplane back to the ramp uneventfully. The airplane sustained substantial damage to the floor beams beneath the cockpit and the station 44 bulkhead. Postaccident examination did not reveal any anomalies with either the flight controls or wheel brake system that would have precluded normal operation. Crosswind Landings The Normal Procedures section of the airplane’s flight manual stated that the maximum demonstrated crosswind component with flaps set to 37.5° was 20 kts measured at 6 feet, equivalent to 27 kts at 50 feet. The manual stated that this was the maximum wind velocity encountered during crosswind landing flight testing and is not considered limiting. The manual stated that, in strong crosswinds, landing with reduced flaps is recommended to reduce the crosswind component (as a percentage of airspeed) at touchdown. The flight manual provided guidance for crosswind landing techniques, stating that the preferred method was for the upwind wing to be lowered during the approach with sufficient opposite rudder applied to align the aircraft with the runway. During the flare and rollout, both of the control inputs must be increased as the airplane slows. The nose wheel should be held on theground during the ground roll, along with “into wind” aileron. Directional control should be maintained with rudder only unless it becomes absolutely necessary to use nose wheel steering. There were no brake application speed limitations, with the manual recommending that brakes should be applied as required after nose wheel contact. Meteorological Information At 0855, the BVU weather reporting station indicated wind from 220° at 23 kts gusting to 28 kts. About that time, the two closest airports, Henderson (HND) and Las Vegas (LAS) both reported similar wind directions, with velocities gusting to 30 kts and 38 kts, respectively. The runways at HND were oriented 17/35 and the runways at LAS were oriented 8/26 and 1/19. Wind at BVU about the time of takeoff was from 210° at 19 kts. A terminal aerodrome forecast for HND current at the time of departure indicated wind velocities through 1100 from 220° at 12 kts gusting to 22 kts, and later increasing to 17 kts, gusting to 27 kts. Runway 27 at BVU was 5,103 ft long and 75 ft wide. The other runway, which was oriented 15/33, was 3,852 ft long and the same width.