# NTSB ANC08FA037: Cessna 170B, N8458D, Tyonek, AK, February 27, 2008 - Type: NTSB accident investigation - Classification: Accident · Fatal · Field investigation · Final report - Date: February 27, 2008, 14:00 local (22:00 UTC) - Place: Tyonek, AK - Coordinates: 61.029724, -151.398605 - Nearby events: https://openairdocs.org/map.md?lat=61.0297&lon=-151.3986&mi=10 - Phase of flight: [Maneuvering](https://openairdocs.org/ntsb-phases/450) (OpenAirDocs' grouping) - Defining event: [Maneuvering: Loss of control in flight](https://openairdocs.org/ntsb-events/240) - Highest injury: Fatal - Injuries: 1 fatal - Status: Completed, report December 11, 2008 - Report: Approved by Office Director - NTSB office: Alaska Regional Office - Parties: Cessna Aircraft Company, FAA-AL-ANC FSDO 03, Teledyne Continental Motors - NTSB case key (mKey): 67590 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=ANC08FA037 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/67590/pdf - Page: https://openairdocs.org/ntsb/ANC08FA037 ## Probable cause The pilot's failure to maintain adequate airspeed to prevent a stall while maneuvering, which resulted in an uncontrolled descent and collision with terrain. ## Findings NTSB's coded findings; those marked are part of the probable cause. - [Performance/control parameters: airspeed](https://openairdocs.org/ntsb-findings/01062010): Aircraft › Aircraft oper/perf/capability · Not attained/maintained (probable cause); cases with it: [Cessna 170B, 13 cases](https://openairdocs.org/ntsb-findings/01062010/cases.md?model=2072306), [All aircraft, 1,681 cases](https://openairdocs.org/ntsb-findings/01062010/cases.md) - [Use of equip/info: aircraft control](https://openairdocs.org/ntsb-findings/02063040): Personnel issues › Task performance · Pilot (probable cause); cases with it: [Cessna 170B, 91 cases](https://openairdocs.org/ntsb-findings/02063040/cases.md?model=2072306), [All aircraft, 9,295 cases](https://openairdocs.org/ntsb-findings/02063040/cases.md) ## Sequence of events The events NTSB coded, in order, by phase of flight. The defining event best describes what happened. - [Maneuvering: Aerodynamic stall/spin](https://openairdocs.org/ntsb-events/241); cases with it: [Cessna 170B, 9 cases](https://openairdocs.org/ntsb-events/241/sequence.md?model=2072306), [All aircraft, 1,529 cases](https://openairdocs.org/ntsb-events/241/sequence.md) - [Maneuvering: Loss of control in flight](https://openairdocs.org/ntsb-events/240) (defining event); cases with it: [Cessna 170B, 19 cases](https://openairdocs.org/ntsb-events/240/sequence.md?model=2072306), [All aircraft, 5,002 cases](https://openairdocs.org/ntsb-events/240/sequence.md) - [Uncontrolled descent: Collision with terr/obj (non-CFIT) ](https://openairdocs.org/ntsb-events/470); cases with it: [Cessna 170B, 52 cases](https://openairdocs.org/ntsb-events/470/sequence.md?model=2072306), [All aircraft, 10,189 cases](https://openairdocs.org/ntsb-events/470/sequence.md) ## Analysis The private pilot departed on a personal cross-country flight with a load of groceries. The flight was reported overdue by family friends, and an emergency locator transmitter signal was detected by search and rescue satellites. The airplane was located in a forested area, having collided with trees and snow-covered terrain in a near vertical, nose down attitude. Visual meteorological conditions prevailed. Postaccident examination of the airframe and engine revealed that the engine was developing power at the time of impact. No preimpact malfunctions of the airframe or engine were discovered. The position of the airplane was indicative of a stall while maneuvering at low altitude. ## Factual narrative HISTORY OF FLIGHT On February 27, 2008, about 1400 Alaska Standard time, a tundra tire-equipped Cessna 170B airplane, N8458D, sustained substantial damage when it collided with trees and snow-covered terrain, about 8 miles southwest of Tyonek, Alaska. The airplane was being operated as a visual flight rules (VFR) cross-country personal flight under Title 14, CFR Part 91, when the accident occurred. The airplane was operated by the pilot. The private certificated pilot, the sole occupant, was killed. Visual meteorological conditions prevailed. The flight originated at Merrill Field, Anchorage, Alaska, about 1328, and was en route to Igiugig, Alaska. 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 accident airplane 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 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 contained the limitation that he must wear glasses for distant vision, and possess glasses for near vision. No personal flight records were received for the pilot, and the aeronautical experience listed on page 3 of this report was obtained from Federal Aviation Administration (FAA) airmen records on file in the Airman and Medical Records Center in Oklahoma City. On the pilot's application for medical certificate, dated February 14, 2007, he indicated that his total aeronautical experience was about 2,400 hours, of which 275 were in the previous 6 months. AIRCRAFT INFORMATION The airplane and the engine had a total time in service of about 2,627 hours. Review of the maintenance records revealed that the most recent annual inspection of the airframe and engine was on October 30, 2007, about 40 hours before the accident. The engine had a major overhaul on April 18, 2002, about 1,535 hours before the accident. METEOROLOGICAL INFORMATION The pilot received a weather briefing via telephone from the Kenai Automated Flight Service Station (AFSS), Kenai, Alaska, at 1233, for a planned flight from Anchorage to Igiugig, via Lake Clark Pass, departing at 1330. The flight service station specialist advised the pilot to expect mostly VFR conditions along the route of flight, with scattered snow showers, especially near higher terrain. A transcript of the weather briefing is included in the public docket of this report. At 1353, an aviation routine weather report (METAR) at Kenai, about 27 miles south-southeast from the accident, was reporting, in part: Wind, 030 degrees (true) at 13 knots; visibility, 10 statute miles; clouds and sky condition, few at 6,500 feet; temperature, 30 degrees F; dew point, 16 degrees F; altimeter, 29.71 inHg. At 1350, Big River Lakes, Alaska, about 21 miles west-southwest of the accident, was reporting calm winds, overcast skies at 6,000 feet, with a visibility of 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 communication was received from the pilot. WRECKAGE AND IMPACT INFORMATION The NTSB IIC, and an FAA inspector from the Anchorage Flight Standards District Office (FSDO), examined the airplane at the accident site on February 28. The airplane was in a forested area, having collided with the snow-covered ground on about a 50 degree, nose-down attitude. At its point of rest, the nose and engine of the airplane were against the base of a large birch tree. The bark of the tree facing the airplane, had been stripped in patches from about 10 feet above the ground to the base, and branches of the tree were broken about 20 feet above the ground. Trees immediately next to the point of rest had broken branches about 40 feet above the ground, but no other trees in the area had evidence of impact. The engine was partially buried in the ground, resting against the base of the birch tree. The tree trunk was between the engine case and the propeller, with one propeller blade resting against the backside of the tree trunk. The backside of the tree trunk had a 45 degree cut into the bark, about 5 feet above the ground, which almost severed the tree. A second cut partially through the tree was about 3 feet above the ground, which split a section of wood from the backside of the tree trunk to the ground. The other propeller blade was buried in the ground. All of the airplane's major components were found at the main wreckage area. The wings were displaced forward of their normal position, and each had extensive spanwise leading edge aft crushing. The leading edge of the left wing had a semicircular aft crush area, about 2 feet inboard from the wingtip. The leading edge of the right wing had two pronounced areas of semicircular aft crushing, with evidence of tree bark at the impact areas. The aft portion of the right wing at the fuselage carry through was torn open at the top of the fuselage. The upper surface of the airplane at its point of rest was on about a 020 degree heading. (All heading/bearings noted in this report are oriented using magnetic north.) The main landing gear struts were broken in an aft direction, and were resting on the surface of the snow. The fuselage, aft of the cockpit, was crushed forward, and the empennage was bent to the left. The horizontal stabilizer, elevator, vertical stabilizer, and the rudder received minor denting. About 5 inches of fuel was found in the left wing fuel tank, and about 1 inch of fuel was found in the right wing fuel tank. The right fuel tank lines were breached. The flight control surfaces remained connected to their respective attach points. The cockpit area was extensively damaged. The engine and firewall were displaced aft and upward, and the instrument panel was crushed forward and upward, almost to the top of the windshield. The engine tachometer was about 2,000 rpm, and the hour meter was 1573.5. Following recovery of the airplane, it was examined in Wasilla, Alaska, on April 8, 2008. The engine was examined at a maintenance facility in Anchorage, on April 9. The parties noted in this report participated in the examination. The fuel selector was on the left tank, and fuel was found within the selector housing. Due to impact damage, the flight controls could not be moved by their respective control mechanisms, but continuity of the flight control cables was established to the cockpit area. The propeller assembly remained connected to the engine crankshaft. One propeller blade had chordwise scratching and aft bending. The second blade had "S" bending, torsional twisting, and aft bending. The engine had impact damage to the nose of the case, the underside, and the left aft portion of the engine. The accessory case at the aft end of the engine was punched through the firewall. The exhaust tubes had malleable bending and folding, producing sharp creases that were not cracked or broken along the creases. Gear and valve train continuity was established, and lubricating oil was found throughout the engine. The oil screen was free of contaminants. The crankshaft accessory gear starter ring had 2 broken gear teeth. The propeller flange was bent and cracked near the radius of the flange base. The magnetos and spark plug leads sustained impact damage, but produced spark at all terminals when functionally tested on a test stand. The massive center electrode sparks plugs had no unusual combustion signatures. The carburetor bowl was fractured, and the butterfly assembly was broken away from the carburetor housing. No e ## Aircraft - Registration: [N8458D](https://openairdocs.org/deregistered/N8458D-2017-07-14), registration cancelled 2017-07-14, S/N 25632, built 1953 (OpenAirDocs) - Reported make and model: CESSNA 170B - Registry model: [Cessna 170B](https://openairdocs.org/model/cessna-170b) (registry code 2072306) (OpenAirDocs) - Registry engine: [Continental 0-300 series](https://openairdocs.org/engine/continental-0-300-series) (registry code 17022, reciprocating) (OpenAirDocs) - Category: Airplane - Serial number: 25632 - Airframe hours: 2627 - Engines: Continental C-145 145 horsepower reciprocating - Damage: Substantial damage - Flight: Personal, Part 91 - Registered owner: Daniel R. Salmon - Airworthiness certificate: Standard, Normal - Last inspection: Annual, October 1, 2007, 40 hours before - Departed: PAMR, Anchorage, AK - Destination: PAIG, Iguigig, AK ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 49; injuries: fatal; private; airplane ratings: single-engine land, single-engine sea; medical: class 3, with waivers/limitations; seat: left; toxicology performed; flight hours: 2,400 total ## Weather - Conditions: Visual (VMC), Day - Wind: 30° at 13 knots - Visibility: 10 statute miles - Lowest ceiling: none - Temperature: 30 °F, dew point 16 °F - Altimeter: 29.70 inHg - Observed at: PAEN, 27 nm away ## FAA reports on this event (1) The FAA's own accident and incident reports, matched to the aircraft by N-number and date (OpenAirDocs). - [Accident 20080227012629A](https://openairdocs.org/incident/20080227012629A), Feb 27, 2008: Cessna 170B, Tyonek, AK, Substantial damage, 1 fatal. (-23) Aircraft struck trees at steep angle, came to rest nose down at base of large cottonwood tree after sliding down the tree. Pilot received weather… From the NTSB's public API. Aircraft are matched to registry aircraft by N-number and event date, checked against the reported serial number, make and model; the registry's history has gaps, so older matches can be wrong. Compare the reported make and model. --- OpenAirDocs.org is an independent research project of [Contrail Labs](https://contraillabs.com/). It is not affiliated with the FAA or the NTSB. Source documents are U.S. government works in the public domain.