Accident Details
On May 29, 2021, at approximately 1312 Alaska Daylight Time, a Cessna 182K (registration N2761Q) sustained substantial damage following an impact with snow- and ice-covered terrain on the north side of Mount Hawkins in Wrangell St Elias National Park, about 77 miles east of Cordova, Alaska. The airplane was operating under 14 CFR Part 91 as a personal flight. The commercial pilot and a passenger, both on board, suffered minor injuries.
Flight Information
The pilot reported completing a preflight inspection and reviewing weather conditions, including winds aloft and METARs, before departing on the cross-country flight. Approximately 2 hours and 15 minutes into the flight, while at an altitude of about 12,500 feet mean sea level (msl), the airplane encountered severe turbulence and windshear, followed shortly by a downdraft. Unable to escape the downdraft, the pilot attempted to level the wings and pitched up as the airplane struck the terrain. The pilot stated there were no preaccident mechanical failures or malfunctions that would have prevented normal operation.
Flight track data showed that after departure, the airplane climbed to about 11,000 ft msl, then turned left to an easterly heading. It maintained an altitude between about 11,000 and 12,900 ft msl. The last recorded data point at 1311:19 indicated an altitude of 11,800 ft msl, groundspeed of 108 knots, and a track of 117°.
Weather Conditions
The accident site and surrounding area were influenced by a relatively strong pressure gradient along the northern Gulf of Alaska, though no frontal boundaries were present. Upper air soundings from Anchorage, Alaska, taken at 0400 and 1600, indicated favorable conditions for severe mountain wave activity between 9,000 and 14,000 ft msl, with updraft and downdraft speeds between 2,000 and 3,000 feet per minute. Such conditions were expected near mountains with peaks between 5,000 and 13,000 ft msl; the mountains south of the accident site fell within this range. Satellite imagery from 1337 showed transverse wave banding at the accident site, indicative of mountain waves.
FAA Advisory Circular AC 00-6B describes mountain waves as atmospheric wave disturbances formed when stable air flows over mountains, producing mechanical turbulence that can extend hundreds of miles downwind. These waves often generate severe to extreme turbulence, with violent downdrafts on the leeward side that can exceed an aircraft's climb capability.
The impact resulted in substantial damage to the fuselage, wings, and left horizontal stabilizer and elevator.