Concrete, WA, USA
C-FISS
Cessna 172
The pilot was following the Skagit River eastbound approximately 1500-1800 feet above sea level when he observed rain showers ahead and he decided to execute a course reversal. He initiated a left turn at 75 miles per hour utilizing two "notches" (20 degrees) of flaps and noted a sink rate. He then applied full power and raised the flaps to one "notch" (10 degrees) during which the sink rate continued. The pilot reported that it "felt like the aircraft was getting sucked down." As the aircraft continued in its left turn towards the rising, tree covered hillside, the pilot executed a controlled crash into the trees and terrain. A topographic chart of the vicinity of the accident showed that the terrain gradient was considerably shallower to the south, and that the left turn initiated by the pilot placed the aircraft flying towards higher gradient terrain. The pilot reported that he had been using carburetor heat throughout the flight and that the aircraft's engine had been performing as expected.
On February 20, 2002, approximately 0800 Pacific standard time, a Cessna 172, C-FISS, registered to and operated by a private individual, and borrowed/being flown by a Canadian certificated commercial pilot, was substantially damaged during an in-flight collision with trees and subsequent collision with terrain while maneuvering. The pilot, who was the only occupant aboard the aircraft, was uninjured. The accident site was located three nautical miles east of Concrete, Washington, at an elevation of 850 feet above mean sea level. The pilot reported scattered clouds and rain showers at the time of the accident, and no flight plan had been filed. The flight, which was personal, was operating in US airspace under 14CFR91 at the time of the accident. The flight departed Langley, British Columbia, approximately 0700, destined for Chilliwack, British Columbia, approximately 27 nautical miles to the east-northeast of Langley. The pilot hiked out from the accident site and reported the accident to law enforcement officials with Skagit County. The pilot was subsequently interviewed on February 22 and submitted a written statement as part of his NTSB Form 6120.1/2 (both attached). He reported that he departed Langley, British Columbia (BC), en route to Chilliwack, BC, and decided to detour into US airspace in the vicinity of the Skagit River following it until reaching Lake Shannon and then returning to Canada. He continued, reporting that he was flying about 1500 feet in elevation roughly eastbound along the river (the River's approximate elevation between 200 and 300 feet above sea level near Concrete). Passing Concrete he noted rain showers ahead and decided to make a 180-degree turn for the return leg. He indicated that he had been using carburetor heat without problems and noted no engine performance problems during the flight. He executed a left turn at 75 miles per hour utilizing two "notches" (20 degrees) of flaps. During the turn he noted a loss of altitude and compensated with power. As the sink rate continued he raised the flaps to one "notch" (10 degrees) and applied full power. He indicated that the sink rate continued and reported in his interview that it "felt like the aircraft was getting sucked down." He reported that as the turn progressed he could see trees and rising terrain ahead, which he tried to avoid. And, that when he determined impact was unavoidable he pulled back on the control column to execute a controlled stall into the trees (refer to NTSB Form 6120.1/2 and ATTACHMENT PI-I). The pilot provided a diagram showing his track over the ground superimposed on a topographic map of the vicinity of the accident site (refer to NTSB Form 6120.1/2). This diagram, along with CHART I (attached) showed the aircraft commencing its left turn about two nautical miles east of Concrete and turning towards rising terrain. The gradient of the terrain rise to the north (direction of the turn) was considerably steeper than the gradient to the south. The pilot also reported that he believed he had encountered a severe downdraft in the vicinity of the accident site.
The pilot's failure to maintain adequate clearance/altitude while reversing course and turning towards rising, tree covered terrain in downdraft conditions. Contributing factors were trees, rising terrain, downdrafts and the pilot's in-flight decision to turn towards rather than away from steeper terrain during his course reversal.
Source: NTSB Aviation Accident Database
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