History of Flight
On February 27, 2008, at about 1400 Alaska Standard time, a tundra tire-equipped Cessna 170B airplane, registration N8458D, collided with trees and snow-covered terrain approximately 8 miles southwest of Tyonek, Alaska. The flight was a visual flight rules (VFR) cross-country personal flight operated by the pilot under Title 14, CFR Part 91. The private certificated pilot, the sole occupant, was killed. Visual meteorological conditions prevailed at the time of the accident. The flight originated from Merrill Field, Anchorage, Alaska, at about 1328, en route to Igiugig, Alaska, and no flight plan was filed.
Federal Aviation Administration (FAA) personnel notified the National Transportation Safety Board (NTSB) investigator-in-charge (IIC) at 1922 that the aircraft had been reported overdue by friends of the pilot. The pilot was returning to his home in Igiugig with a load of groceries. Search and rescue personnel located the accident site at about 1953, and the pilot was transported to a hospital in Anchorage.
Personnel Information
The pilot held a private pilot certificate with airplane single-engine land and single-engine sea ratings. His most recent third-class medical certificate was issued on February 14, 2007, and required that he wear corrective lenses for distant vision and possess glasses for near vision. No personal flight records were received; aeronautical experience obtained from FAA records indicated approximately 2,400 total hours, with 275 hours in the previous 6 months, as noted on his February 14, 2007 medical certificate application.
Aircraft Information
The airplane and engine had accumulated approximately 2,627 total service hours. Maintenance records showed the most recent annual inspection of airframe and engine was on October 30, 2007, about 40 hours before the accident. The engine had undergone a major overhaul on April 18, 2002, about 1,535 hours prior.
Meteorological Information
The pilot received a weather briefing via telephone from the Kenai Automated Flight Service Station (AFSS) at 1233 for a planned flight from Anchorage to Igiugig via Lake Clark Pass, departing at 1330. The specialist advised mostly VFR conditions along the route with scattered snow showers, especially near higher terrain. At 1353, an aviation routine weather report (METAR) from Kenai, about 27 miles south-southeast of the accident, reported wind from 030 degrees true at 13 knots, visibility 10 statute miles, few clouds at 6,500 feet, temperature 30°F, dew point 16°F, and altimeter 29.71 inHg. At 1350, Big River Lakes, about 21 miles west-southwest of the accident, reported calm winds, overcast skies at 6,000 feet, and visibility 20 miles.
Communications
The pilot contacted the Merrill Field Air Traffic Control Tower (ATCT) at 1325 and was cleared for takeoff at 1328. No further communications were received from the pilot after departure.
Wreckage and Impact Information
The NTSB IIC and an FAA inspector from the Anchorage Flight Standards District Office examined the accident site on February 28. The aircraft came to rest in a forested area after colliding with the ground at approximately a 50-degree nose-down attitude. The nose and engine were against the base of a large birch tree, with bark stripped from the tree from about 10 feet above the ground to the base, and branches broken about 20 feet up. Adjacent trees had broken branches about 40 feet high, but no other impact evidence was found elsewhere. The engine was partially buried, resting against the tree trunk, which was between the engine case and propeller. One propeller blade was against the backside of the trunk, which had a 45-degree cut into the bark about 5 feet above ground almost severing the tree; a second cut partially through the tree about 3 feet above ground split wood from the backside to the ground. The other propeller blade was buried in the ground.
All major components were present at the main wreckage area. Wings were displaced forward with extensive spanwise leading edge aft crushing. The left wing had a semicircular aft crush area about 2 feet inboard from the wingtip; the right wing had two pronounced semicircular aft crush areas with tree bark evidence. The aft portion of the right wing at the fuselage carry-through was torn open at the top. The aircraft’s upper surface at rest was oriented on about a 020-degree magnetic heading. Main landing gear struts were broken aft and resting on snow. The fuselage aft of the cockpit was crushed forward; the empennage was bent left. Horizontal stabilizer, elevator, vertical stabilizer, and rudder had minor denting.
Approximately 5 inches of fuel were found in the left wing tank and about 1 inch in the right wing tank; the right fuel tank lines were breached. Flight control surfaces remained attached to their respective attach points. The cockpit was extensively damaged; the engine and firewall displaced aft and upward; the instrument panel crushed forward and upward almost to the windshield top. The engine tachometer indicated about 2,000 rpm, and the hour meter read 1573.5.
Following recovery, the aircraft was examined in Wasilla, Alaska, on April 8, 2008, and the engine at a maintenance facility in Anchorage on April 9. The fuel selector was on the left tank, and fuel was present in the selector housing. Due to impact damage, flight controls could not be moved by their mechanisms, but cable continuity to the cockpit was established. The propeller assembly remained attached to the crankshaft; one blade had chordwise scratching and aft bending; the second blade had S-bending, torsional twisting, and aft bending. The engine case sustained impact damage to the nose, underside, and left aft portion; the accessory case was punched through the firewall. Exhaust tubes had malleable bending and folding with sharp creases but no cracks. Gear and valve train continuity was established; lubricating oil was found throughout; the oil screen was free of contaminants. The crankshaft accessory gear starter ring had two broken gear teeth; the propeller flange was bent and cracked near its base radius. Magnetos and spark plug leads had impact damage but produced spark at all terminals when tested. Spark plugs showed no unusual combustion signatures. The carburetor bowl was fractured, and the butterfly assembly was broken from the housing. No evidence of preimpact engine anomalies was discovered.
Medical and Pathological Information
A postmortem examination performed under the authority of the Alaska State Medical Examiner on February 29, 2008, attributed the cause of death to multiple blunt force injuries. A toxicological examination by the FAA's Civil Aeromedical Institute (CAMI) on April 10, 2008, was negative for alcohol and drugs.
Search and Rescue
The Alaska Rescue Coordination Center (RCC) received a composite emergency transmitter locator (ELT) signal in the accident area at about 1555, and an overflying airplane also reported hearing the ELT. No ELT signal was heard during a satellite pass at 1602. The Alaska State Trooper post in Soldotna was notified at about 1618. The RCC requested Civil Air Patrol (CAP) search aircraft from Kenai at about 1702, which were airborne by about 1751 but could not cross Cook Inlet due to insufficient cloud ceiling (needed 3,500 feet msl). At about 1806, the RCC requested search personnel from the 212th Rescue Squadron. At about 1902, the aircraft was reported overdue by a family friend. At about 1930, the 212th helicopter began searching the area and located the accident site at about 1953.
Additional Information
The Safety Board released the wreckage to the owner’s representatives on May 19, 2008. No parts or components were retained.