# NTSB LAX03LA106: Cessna 421C, N26533, Crescent City, CA, March 5, 2003 - Type: NTSB accident investigation - Classification: Accident · No injuries · Limited investigation · Final report - Date: March 4, 2003, 22:45 local (Mar 5, 2003, 06:45 UTC) - Place: Crescent City, CA - Coordinates: 41.780277, -124.236389 - Nearby events: https://openairdocs.org/map.md?lat=41.7803&lon=-124.2364&mi=10 - Phase of flight: [Landing](https://openairdocs.org/ntsb-phases/550) (OpenAirDocs' grouping) - Highest injury: No injuries - Injuries: 3 uninjured - Status: Completed, report December 28, 2004 - Report: Approved by Office Director - Parties: Federal Aviation Administration - NTSB case key (mKey): 56600 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=LAX03LA106 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/56600/pdf - Page: https://openairdocs.org/ntsb/LAX03LA106 ## Probable cause The separation of the upper and lower right main landing gear scissor links due to improper maintenance, which resulted in a ground loop, and the collapse of the right main landing gear during the landing roll. ## Sequence of events In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf). - Airframe/component/system failure/malfunction, landing - roll - maintenance - improper, company maintenance personnel (cause) - landing gear,main gear strut scissors - disconnected (cause) - Loss of control - on ground/water, landing - roll - ground loop/swerve - encountered - directional control - not possible - Main gear collapsed, landing - roll ## Analysis The right main landing gear scissors separated during the landing roll, resulting in a ground loop and the collapse of the right main landing gear. Post accident examination of the right landing gear scissors assembly revealed that a hinge bolt assembly had failed. Recent maintenance had reportedly been performed on both main landing gears. A Cessna Service Information Letter, ME83-37, dated November 23, 1983, recommended main landing gear scissor washer replacement for airplanes with serial numbers that included the accident airplane. The Service Letter recommended replacement of the two outer washers on the main landing gear scissor link for improved service life, and main gear wheel alignment retension. The Service Letter called for the installation of a new AN175-20 scissor bolt, and one 5045018-2 washer under the head of the bolt for each main landing gear scissors. Post accident examination of the scissor assembly revealed two damaged washers under the head of the scissors bolt, with diameters only slightly larger than the extreme hex points of the bolt head. The two washers were significantly smaller than the recommended washers, and were extruded, or bent towards, the scissor bolt head, which allowed the upper and lower scissor assembly to disconnect. ## Factual narrative On March 4, 2003, at 2245 Pacific standard time, a Cessna 421C, N26533, veered off the runway and ground looped while landing at the Crescent City, California, airport. The airplane was operated by Westlog, Inc., d.b.a., Cal-Ore Life Flight as a positioning flight under 14 CFR Part 91. The airline transport pilot and two passengers were not injured. The airplane was substantially damaged. Visual meteorological conditions prevailed, and no flight plan had been filed. The flight originated at Medford, Oregon, at an undetermined time. Post accident examination of the right landing gear retract scissors assembly revealed that a hinge bolt assembly had failed. The parts were recovered by Federal Aviation Administration inspectors for detailed examination of the hardware and the maintenance manual. Recent maintenance had reportedly been performed on both main landing gears. A Cessna Service Information Letter ME83-37, dated November 23, 1983, recommended main landing gear scissor washer replacement for Cessna models 401 thru 421, with serial numbers that included the accident airplane. The purpose was to recommend replacement of the two outer washers on the main landing gear scissor link for improved service life and main gear wheel alignment retension. A Cessna Service Kit SK421-118, provided the necessary parts to comply with ME83-37. Step 3.b calls for the installation of a new AN175-20 scissor bolt and one 5045018-2 washer under the head of the bolt for each main landing gear scissors. The 5045018-2, 0.75-inch diameter washer is 0.063-inch thick and made of SAE 4130 steel with an inside diameter of 0.313-inch, with a tolerance of +0.031-inch and minus zero. The AN 175-20 scissors bolt is 0.3125-inch outside diameter. Post accident examination of the scissor assembly revealed two damaged washers under the head of the scissors bolt with diameters only slightly more than the extreme hex points of the bolt head, measuring about 0.564-inch. One washer internal diameter was about 0.453-inch and 0.024-inch thick; the other internal diameter was about 0.325-inch and about 0.032-inch thick. The washer material appears to be stainless steel. The two washers were extruded, or bent towards the scissor bolt head, allowing for the upper and lower scissor assembly to disconnect. ## Aircraft - Registration: [N26533](https://openairdocs.org/aircraft/N26533), registered now, S/N 421C0686, built 1979 (OpenAirDocs) - Reported make and model: Cessna 421C - Registry model: [Cessna 421C](https://openairdocs.org/model/cessna-421c) (registry code 2076016) (OpenAirDocs) - Registry engine: [Continental GTSIO-520-C](https://openairdocs.org/engine/continental-gtsio-520-c) (registry code 17035, reciprocating) (OpenAirDocs) - Category: Airplane - Serial number: 421C0686 - Airframe hours: 5886.3 - Engines: Continental GTSIO-520-C 300 horsepower reciprocating - Damage: Substantial damage - Flight: Positioning, Part 91 - Registered owner: Westlog Inc. - Airworthiness certificate: Standard, Normal - Last inspection: Annual, February 20, 2003, 13 hours before - Departed: MFR, Medford, OR - Destination: CEC, Crescent City, CA - Airport: CEC, Crescent City, runway 35, 5,002 × 150 ft, asphalt ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 61; injuries: none; airline transport; airplane ratings: single-engine land, multi-engine land; instrument ratings: airplane; medical: class 2, valid medical--w/ waivers/lim; last flight review February 20, 2003; seat: left; flight hours: 10,518 total, 933 in this make and model ## Weather - Conditions: Visual (VMC), Night - Wind: 350° at 12 knots, gusting 19 - Visibility: 8 statute miles - Lowest ceiling: none - Temperature: 48 °F, dew point 46 °F - Altimeter: 30.02 inHg - Observed at: CEC ## 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 20030304027299A](https://openairdocs.org/incident/20030304027299A), Mar 4, 2003: Cessna 421C, Crescent City, CA, Substantial damage. (-23) Aircraft made a normal landing touchdown on runway centerline. After touchdown, the aircraft veered right and the pilot was unable to correct with… 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.