# NTSB ANC03LA126: Cessna 170A, N9006A, Skwentna, AK, September 25, 2003 - Type: NTSB accident investigation - Classification: Accident · No injuries · Limited investigation · Final report - Date: September 25, 2003, 14:00 local (22:00 UTC) - Place: Skwentna, AK - Coordinates: 61.926666, -153.179992 - Nearby events: https://openairdocs.org/map.md?lat=61.9267&lon=-153.1800&mi=10 - Phase of flight: [Landing](https://openairdocs.org/ntsb-phases/550) (OpenAirDocs' grouping) - Highest injury: No injuries - Injuries: 1 uninjured - Status: Completed, report April 28, 2004 - Report: Approved by Office Director - NTSB office: Alaska Regional Office - Parties: FAA-AL-ANC FSDO 03 - NTSB case key (mKey): 58054 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=ANC03LA126 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/58054/pdf - Page: https://openairdocs.org/ntsb/ANC03LA126 ## Probable cause An overload failure of the axle retaining nut/bolt assembly, which resulted in the separation of the axle/wheel assembly, and subsequent collapse of the right main landing gear strut during the landing roll. ## Sequence of events In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf). - Main gear collapsed, landing - roll - miscellaneous,bolt/nut/fastener/clamp/spring - overload (cause) - landing gear,axle - separation - landing gear,main gear strut - collapsed ## Analysis The commercial certificated pilot was landing on a remote gravel area that was about 1,000 feet long, and 30 feet wide. The pilot said that during the landing roll, the airplane's right main landing gear suddenly collapsed. As the airplane slid on the gravel, the right gear strut was torn out of the fuselage, and the airplane received additional damage to the fuselage and right wing. After the accident, the pilot said he examined the right gear strut and discovered the right axle and wheel assembly were missing from the outboard end of the gear strut. After a search, the pilot located the wheel assembly and discovered that the nuts utilized to secure the attaching axle bolts to the gear strut, were stripped from their respective bolts. The pilot said he decided to wait until the next day before activating his airplane's emergency locator transmitter. He further said he decided to destroy his airplane by setting it on fire, as it would have been economically unfeasible to pay for repairs and helicopter transportation charges to remove the airplane from its remote location. The airplane was observed by search personnel as having burned. ## Factual narrative On September 25, 2003, about 1400 Alaska daylight time, a tundra tire-equipped Cessna 170A airplane, N9006A, sustained substantial damage when the right main landing gear strut collapsed during the landing roll at a remote area, about 57 miles west-southwest of Skwentna, Alaska. The airplane was being operated as a visual flight rules (VFR) local area personal flight under Title 14, CFR Part 91, when the accident occurred. The airplane was operated by the pilot. The commercial certificated pilot, the sole occupant, was not injured. Visual meteorological conditions prevailed. No flight plan was filed, nor was one required. During a telephone conversation with the National Transportation Safety Board (NTSB) investigator-in-charge (IIC), on September 30, the pilot reported that he landed toward the east on a gravel site in an area known as Hellsgate. The landing area was oriented east/west, and was about 1,000 feet long, and 30 feet wide. The pilot said that during the landing roll, the airplane's right main landing gear suddenly collapsed. As the airplane slid on the gravel, the right gear strut was torn out of the fuselage, and the airplane received additional damage to the fuselage and right wing. After the accident, the pilot said he examined the right gear strut, and discovered the right axle and wheel assembly were missing from the outboard end of the gear strut. After a search, the pilot located the wheel assembly and discovered that the nuts utilized to secure the attaching axle bolts to the gear strut, were stripped from their respective bolts. The pilot said he decided to wait until the next day, September 26, before activating his airplane's emergency locator transmitter. He further said he decided to destroy his airplane by setting it on fire, as it would have been economically unfeasible to pay for repairs and helicopter transportation charges to remove the airplane from its remote location. Search personnel located the accident site on September 26, and alerted a friend of the pilot's, who picked up the pilot on September 27. According to search personnel, the accident site was located along the South Fork of the Kuskokwim River, at Ptarmigan Pass, in the Alaska Mountain Range. The airplane was observed by search personnel as having burned. ## Aircraft - Registration: [N9006A](https://openairdocs.org/deregistered/N9006A-2013-05-17), registration cancelled 2013-05-17, S/N 18761, built 1949 (OpenAirDocs) - Reported make and model: Cessna 170A - Registry model: [Cessna 170A](https://openairdocs.org/model/cessna-170a) (registry code 2072304) (OpenAirDocs) - Registry engine: [Continental C145 series](https://openairdocs.org/engine/continental-c145-series) (registry code 17012, reciprocating) (OpenAirDocs) - Category: Airplane - Serial number: 18761 - Airframe hours: 3400 - Engines: Continental C-145 145 horsepower reciprocating - Damage: Substantial damage - Flight: Personal, Part 91 - Registered owner: Steven D. Lewis - Airworthiness certificate: Standard, Normal - Last inspection: Annual, May 30, 2003, 100 hours before - Departed: SKWENTNA, AK ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 52; injuries: none; commercial; airplane ratings: single-engine land, single-engine sea, multi-engine land; instrument ratings: airplane; medical: class 2, valid medical--w/ waivers/lim; last flight review February 28, 2003; seat: left; flight hours: 5,000 total, 100 in this make and model, 5,000 as pilot in command, 150 in the last 90 days, 75 in the last 30 days, 5 in the last 24 hours ## Weather - Conditions: Visual (VMC), Day - Wind: calm - Visibility: 30 statute miles - Lowest ceiling: 8,000 ft overcast - Temperature: 39 °F ## 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 20030925026909A](https://openairdocs.org/incident/20030925026909A), Sep 25, 2003: Cessna 170A, Skwentna, AK, Substantial damage. (-23) Mr. Lewis was landing west on a remote "bush" gravel runway. He described the runway to be approximately 50 x 1000 feet, gravel, level in all directions… 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.