ANC10FA004

The pilot's decision to maneuver at a low altitude over rising terrain in conditions conducive to turbulence/downdrafts, resulting in a loss of control and impact with terrain.

The pilot reported that he was flying a private wildlife biologist over an area of a national park to observe and track wolves using radio telemetry. The pilot stated that during the initial 2 hours of the flight there was no significant turbulence, only what he characterized as light chop. The pilot indicated that just prior to the accident he flew over a ridge that rose to about 500 to 800 feet above the ground. When the pilot maneuvered the airplane to reverse direction toward the ridge, it encountered turbulence and downdrafts that increased the airplane’s bank angle and pushed it towards the ground, ultimately causing it to strike trees and the ground. A postaccident examination of the airplane revealed no mechanical malfunctions or failures that would have precluded normal operation. Additionally, a warning had been issued to airmen for the possibility of severe or greater turbulence, severe icing, low-level wind shear, and instrument flight conditions in the general area at the time of the accident.

HISTORY OF FLIGHT On October 14, 2009, about 1430 Alaska daylight time, a Cessna A185E airplane, N2764J, received substantial damage when it impacted trees and terrain, about 28 miles west of Healy, Alaska. The airplane was registered to and operated by the pilot under the provisions of Title 14 Code of Federal Regulations (CFR) Part 91. The commercial pilot was seriously injured, and his passenger was killed. Visual meteorological conditions prevailed, and no flight plan was filed for the local aerial photography/animal survey flight, which originated from the Denali Airport, McKinley Park, Alaska, about 1215. A friend of the pilot called the Federal Aviation Administration (FAA) the evening of October 14 after becoming concerned that the flight had not returned to the airport at the expected time. The flight was officially reported overdue to the FAA on October 15, at 0045. On the morning of October 15, search personnel from the Civil Air Patrol, Alaska State Troopers, and Alaska Air National Guard were dispatched to search along the pilot’s reported route of flight. There was no emergency locator transmitter (ELT) signal from the airplane. The incinerated wreckage was located on October 15, about 1500, in an area of mountainous, tree-covered terrain by airborne searchers. In a written statement and during subsequent interviews with the Safety Board investigator-in-charge (IIC), the pilot reported that after departure, he proceeded in a west-southwest circuit from the airport to conduct a local aerial observation flight in order to track wolves throughout the Denali National Park, using radio telemetry. The passenger, a private biologist who had frequently monitored wolves in the park, was tracking and monitoring movement of the wolves as well as conducting aerial photography of the wolf packs. The pilot further reported that during aerial observations at four locations about 10 to 15 miles north-northeast of the accident site, he noted the wind was generally from the north at 5 to 10 knots, with occasional "light chop." The pilot altered his course to the west, and eventually to the south-southeast, to the east fork of the Toklat River. As the airplane reached the area of the upper east fork of the river, the pilot said he began arcing north-northwest along the river’s west side on his initial approach over the intended observation area. He stated that they initially flew over the observation area, and crossed a low ridge line that rose to the west, about 500 to 800 feet above ground level (agl). He said he then started a left 180-degree turn back towards the observation area "in an attempt to begin observations." The pilot indicated that about half to three quarters of the way through the turn, the airplane "encountered unexpected turbulence and drafts that rolled the wings steeper into the left bank and induced a continuing loss of altitude." He said when he rolled the wings level and applied full power, the airplane was heading south-southwest, towards the rising ridge. He rolled the airplane into a shallow left bank in a climb-pitch attitude "in an attempt to reach lowering terrain and avoid the ridge without inducing a stall." He said that downdrafts continued to force the airplane down towards the ridge line where it impacted. After impact, the pilot said he blacked out momentarily. As he awoke, he saw smoke and flames within the cabin area, and he left the airplane while yelling to his passenger to get out. He stated that at no time did he receive any reply from his passenger. The pilot attempted to re-enter the airplane through the baggage door, but was unsuccessful due to the flames. The pilot remained near the wreckage over night. In the morning hours of October 15, he walked along the east fork of the Toklat River, about 7 miles upstream to a nearby road. He continued to walk about 9 miles on the road until he saw a group of people camping. The group walked 5 miles to their car, and the pilot was taken to town for medical attention. PERSONNEL INFORMATION The pilot, age 35, held a commercial pilot certificate with airplane single-engine land, airplane multi-engine land, and instrument ratings. A second-class airman medical certificate issued April 10, 2009, with no limitations stated. The pilot reported that as of December 26, 2009, he had a total flight time of 4,400 hours, of which 55 hours were in the accident make/model airplane. AIRCRAFT INFORMATION The four-seat, high-wing, fixed-gear tailwheel equipped airplane, serial number (S/N) 185-1514, was manufactured in 1969. It was powered by a Continental IO-520-D (9) engine, serial number 282982, and equipped with a two-blade McCauley constant speed propeller, model number D2A34C58-0, serial number 842378. The pilot registered the airplane with the FAA on April 13, 2009. Review of copies of maintenance logbook records revealed that a 100-hour/annual inspection was conducted April 16, 2009, at a recorded tachometer reading of 2,350 hours, airframe total time of 3,474.80 hours, and engine time of 574 hours since factory remanufacture, and 6.24 hours since top overhaul. The tachometer and the Hobbs hour-meter were not observed at the accident site. METEOROLOGICAL INFORMATION A review of recorded data from the automated weather observation station, about 31 miles west-northwest of the accident site, at an elevation of 1,720 feet, revealed at 1456 Alaska daylight time, conditions were: wind from 010 degrees at 10 knots, visibility 10 statute miles, overcast cloud layer at 300 feet, temperature 1 degree Celsius, dew point minus 1 degree Celsius, and an altimeter setting of 29.49 inches of Mercury. An AIRMET issued for the northern half of Alaska at 1045 was valid until 1700. The AIRMET stated that possible severe or greater turbulence, severe icing, low level wind shear, and IFR conditions could exist in the area during the specified time frame. WRECKAGE AND IMPACT INFORMATION The accident site was adjacent to the east fork of the Toklat River within the Denali National Park. Examination of the accident site revealed several topped trees, about 30 to 40 feet in height. The outboard portion of the right elevator was observed below the first tree, which was the first identified point of contact (IPC). The fiberglass right wingtip was located about 20 feet from the IPC, near a second grouping of topped trees. The left outboard horizontal stabilizer and section of elevator were located within a topped tree, about 20 feet in height, and about 80 feet from the IPC. The main wreckage was located about 110 feet from the IPC. Portions of Plexi- glass were observed about 50 feet beyond the main wreckage. The wreckage debris energy path was oriented along an approximate heading of about 230 degrees magnetic. The main wreckage came to rest upright, oriented on an approximate heading of 180 degrees magnetic at an elevation of about 3,040 feet mean sea level. From the southern side of the wreckage debris path, looking north, the damaged trees along the northwest edge of the debris path were topped and or damaged higher than the trees on the northeast side of the debris path. Examination of the airplane reveled that a majority of the fuselage and right wing were consumed by fire. The left wing was partially consumed by fire. All major structural components of the airframe were located within the wreckage debris path. Examination of the airframe and flight control system revealed no evidence of preimpact mechanical malfunction. The engine was partially attached to the engine mounts. The propeller remained attached to the engine crankshaft propeller flange. One blade was bent and twisted aft into the engine cowling. The blade had chord-wise scratching on the propeller blade face. The opposing propeller blade was twisted and buried into the soft ground. Chord-wise scratching was observed on the rear of t