# NTSB ANC97LA120: Cessna 185, N5246E, Chickaloon, AK, August 9, 1997 - Type: NTSB accident investigation - Classification: Accident · No injuries · Limited investigation · Final report - Date: August 9, 1997, 11:00 local (19:00 UTC) - Place: Chickaloon, AK - Coordinates: 61.739234, -148.220458 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=61.7392&lon=-148.2205&mi=10 - Phase of flight: [Landing](https://openairdocs.org/ntsb-phases/550) (OpenAirDocs' grouping) - Highest injury: No injuries - Injuries: 3 uninjured - Status: Completed, report November 10, 1998 - Report: Approved by Office Director - NTSB office: Alaska Regional Office - NTSB case key (mKey): 3043 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=ANC97LA120 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/3043/pdf - Page: https://openairdocs.org/ntsb/ANC97LA120 ## Probable cause inadequate maintenance inspection and failure of the left main landing gear attachment due to fatigue. A factor was continuous use of the airplane for rough area, off-airport landings. ## Sequence of events In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf). - Main gear collapsed, landing - roll - landing gear,main gear attachment - fatigue (cause) - maintenance,inspection - inadequate, other maintenance personnel (cause) - landing gear,main gear attachment - separation ## Analysis As the tundra tire equipped airplane slowed to 25 knots during the landing roll on a gravel strip, the left main landing gear leg separated at the wheel attachment bolt holes. The airplane ground looped, and both wingtips were damaged. Metallurgical examination revealed multiple fatigue cracks originating from the bolt holes. The airplane had been used extensively for off-airport landings, both on wheels and skis. The failed gear leg had been inspected for cracks 806 flight hours and 16 months prior to the accident. ## Factual narrative On August 9, 1997, at 1100 Alaska daylight time, a Cessna 185 tundra tire equipped airplane, N5246E, sustained substantial damage when it contacted terrain during landing roll on a Chickaloon River off airport landing site, 30 miles north of Chickaloon, Alaska. The commercial certificated pilot and two passengers were uninjured. The airplane was operated by Talkeetna Air Taxi, Inc., of Talkeetna, Alaska. The flight was conducted under 14 CFR Part 135 as an on demand air taxi from Palmer to the Chickaloon River. Visual meteorological conditions prevailed at the time of the accident, and a company VFR flight plan was filed. The pilot stated that during landing roll, while decelerating through 25 knots, the left main wheel separated at the axle mounting bolts. The airplane ground looped, and the propeller and wing contacted the ground. Metallurgical inspection conducted at the NTSB laboratory revealed multiple fatigue crack origin sites on the attaching bolt hole walls of the left hand main landing gear leg. Scanning electron microscope inspection revealed a fatigue crack originating from corrosion pits. Metallurgical composition was consistent with 6150 steel specified by Cessna. Hardness was tested to be 50.8 to 52.7 HRC. The specified HRC range is 48.3 to 50.0 HRC. The operator reported that this landing gear leg had been damaged during a lake landing in February 1996. It was removed, arched, heat treated, and reinstalled on April 12, 1996. At this time, landing gear leg serial number 814048 underwent a magnaflux inspection for cracks at 5437 airframe hours. This was 806 hours prior to the accident. Previous magnaflux inspections had been performed at 5086 airframe hours, and 5415 airframe hours. Cessna maintenance procedures do not have required inspections, or life limits, on landing gear legs. The FAA does not mandate any inspection interval for landing gear in off airport use. Landing gear legs are replaced "on condition." The air taxi company maintains the airplane on an FAA approved continuing airworthiness inspection schedule, and voluntarily performs non-destructive magnaflux inspections of landing gear legs for cracks. These inspections are performed due to the use of the airplane for off-airport wheel and ski landings. ## Aircraft - Registration: [N5246E](https://openairdocs.org/deregistered/N5246E-2007-09-18), registration cancelled 2007-09-18, S/N 18503943, built 1979 (OpenAirDocs) - Reported make and model: Cessna 185 - Registry model: [Cessna A185F](https://openairdocs.org/model/cessna-a185f) (registry code 2072821) (OpenAirDocs) - Registry engine: [Continental IO-520 series](https://openairdocs.org/engine/continental-io-520-series) (registry code 17032, reciprocating) (OpenAirDocs) - Category: Airplane - Serial number: 185-03943 - Airframe hours: 6243 - Engines: Continental IO-520-D 300 horsepower reciprocating - Damage: Substantial damage - Flight: Part 135 - Registered owner: Talkeetna Air Taxi, Inc - Airworthiness certificate: Standard, Normal - Last inspection: AAIP, August 4, 1997, 25 hours before - Departed: TKA, TALKEETNA, AK - Destination: CHICKALOON RIVR, AK - Flight plan: Company VFR ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 30; commercial; airplane ratings: single-engine land, multi-engine land, single-engine sea; instrument ratings: airplane; medical: class 2, valid medical--no waivers/lim.; seat: left; flight hours: 4,500 total, 3,000 in this make and model, 4,500 as pilot in command, 275 in the last 90 days, 80 in the last 30 days, 3 in the last 24 hours ## Weather - Conditions: Visual (VMC), Day - Wind: calm - Visibility: 40 statute miles - Lowest ceiling: 10,000 ft overcast - Temperature: 55 °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 19970809025969A](https://openairdocs.org/incident/19970809025969A), Aug 9, 1997: Cessna A185F, Chickaloon, AK, Substantial damage. On aug. 9, 1997 N5246E, CE-185 piloted by paule roderick, owner of talketna air taxi inc, experienced aleft gear leg failure while on roll-out after landing on… ## Other investigations on N5246E (4) 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. - [NTSB ANC03LA057](https://openairdocs.org/ntsb/ANC03LA057), Jun 9, 2003: Cessna 185 (N5246E), Talkeetna, AK, substantial damage. Probable cause: The pilot's excessive taxi speed while attempting to turn the airplane in soft snow, which resulted in a nose over. A factor in the accident was soft snow. - [NTSB ANC96LA111](https://openairdocs.org/ntsb/ANC96LA111), Aug 4, 1996: Cessna 185 (N5246E), Healy, AK, substantial damage. Probable cause: The inadequate visual outlook by the pilots of both aircraft, and their failure to see and avoid the other aircraft. A factor associated with the accident was sunglare affecting the helicopter… - [NTSB ANC96LA030](https://openairdocs.org/ntsb/ANC96LA030), Mar 4, 1996: Cessna 185F (N5246E), Skwentna, AK, substantial damage. Probable cause: the pilot's selection of an unsuitable area for landing. A factor associated with the accident was the rough and uneven terrain. - [NTSB ANC90LA136](https://openairdocs.org/ntsb/ANC90LA136), Aug 8, 1990: Cessna 185 (N5246E), Talkeetna, AK, substantial damage. Probable cause: FAILURE OF THE RIGHT MAIN LANDING GEAR SPRING UPON LANDING. 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.