# NTSB MIA06LA130: Cessna 550, N466SS, Marathon, FL, July 22, 2006 - Type: NTSB accident investigation - Classification: Accident · No injuries · Limited investigation · Final report - Date: July 22, 2006, 12:30 local (16:30 UTC) - Place: Marathon, FL - Coordinates: 24.72611, -81.051391 - Nearby events: https://openairdocs.org/map.md?lat=24.7261&lon=-81.0514&mi=10 - Phase of flight: [Taxi](https://openairdocs.org/ntsb-phases/250) (OpenAirDocs' grouping) - Highest injury: No injuries - Injuries: 4 uninjured - Status: Completed, report July 25, 2007 - Report: Approved by Office Director - Parties: FAA Flight Standards District Office - NTSB case key (mKey): 64373 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=MIA06LA130 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/64373/pdf - Page: https://openairdocs.org/ntsb/MIA06LA130 ## Probable cause The separation for undetermined reasons of the stud (P/N 6541204-5) which secures the main landing gear actuator assembly side brace to the main landing gear outer cylinder, allowing partial collapse of the right main landing gear while taxiing after landing. ## Sequence of events In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf). - Main gear collapsed, taxi - from landing - landing gear,normal retraction/extension assembly - separation - reason for occurrence undetermined (cause) ## Analysis After takeoff the landing gear retracted normally and the flight proceeded to the destination airport. While descending from 19,000 to 15,000 feet near the destination airport, a sound was heard that a passenger thought was a lightning strike. The flight leveled off at 15,000 feet, and the only discrepancy the pilot noted was the failure of the No. 1 communication transceiver to transmit. The flight continued to the destination airport and during normal extension of the landing gear, the pilot "noticed an extra clunk" sound. All landing gears were indicating down and locked and the airplane was landed uneventfully. While taxiing to the ramp, the right wing dropped. He secured the airplane, and noted the right main landing gear was displaced outboard. Marks from the right main landing gear tire were noted leading off the runway onto the taxiway, and a stud (P/N 6541204-5), which secures the main landing gear actuator assembly side brace to the main landing gear outer cylinder, was not in position and was not located for the right main landing gear. Examination of the actuator assembly attach stud tapered hole of the right main landing gear outer cylinder (P/N 5541320-6) revealed no unusual markings and the inside diameter was within limits. ## Factual narrative On July 22, 2006, about 1230 eastern daylight time, a Cessna 550, N466SS, registered to and operated by Capital Buyers of Delaware, Inc., experienced partial collapse of the right main landing gear while taxiing after landing at The Florida Keys Marathon Airport, Marathon, Florida. Visual meteorological conditions prevailed at the time and an instrument flight rules (IFR) flight plan was filed for the 14 CFR Part 91 corporate/executive flight from Dennis F. Cantrell Field Airport, Conway, Arkansas, to The Florida Keys Marathon Airport. The airplane was substantially damaged and the commercial-rated pilot and three passengers were not injured. The flight originated about 0930, from Dennis F. Cantrell Field Airport. The pilot stated that after takeoff the landing gear retracted normally and the flight proceeded to the destination airport. While en-route to the destination airport and descending from 19,000 feet to 15,000 feet, he heard a sound, and one of the passengers who is the owner advised seeing a lightning strike. The flight leveled off at 15,000 feet and the only discrepancy he noted was the failure of the No. 1 communication transceiver to transmit. The flight continued to the destination airport and he cancelled his IFR clearance. While turning onto the downwind leg flying between 165 and 170 knots, 15-18 degrees of left bank, with approach flaps extended, he lowered the landing gear using the normal method and he "noticed an extra clunk" sound. He noted 3 green lights indicating all landing gears were down and locked turned left base and final. He again confirmed 3 green lights prior to a smooth landing. During the landing roll he activated the thrust reversers and turned left onto a parallel taxiway. He then turned right onto a ramp where the airplane was to be parked and he felt the right wing drop and thought the right main landing gear tire was deflated/blown. He secured the airplane and noticed that the right main landing gear was displaced outboard. He then examined the taxiway and noticed that a mark associated with the right main landing gear tire was noted where the airplane was taxied off the runway onto the parallel taxiway. He further reported that there was no abnormal indication of the landing gear after extending the landing gear for landing or while taxiing prior to the partial collapse of the right main landing gear. The airplane was repaired before NTSB notification, which occurred on August 2, 2006. Maintenance personnel later reported to the NTSB that during recovery of the airplane, a stud (P/N 6541204-5), which secures the main landing gear actuator assembly side brace to the main landing gear outer cylinder, was not in position and was not located for the right main landing gear. Prior to NTSB notification, components of the right main landing gear were sent for inspection/repair to Cessna Aircraft Company, located in Wichita, Kansas. Following inspection/repair, the components were sent to a Cessna service center located in Orlando, Florida, for installation onto the airplane. Following NTSB notification, the right main landing gear outer cylinder (P/N 5541320-6) was resubmitted to Cessna Aircraft Company for further examination. Examination of the actuator assembly attach stud tapered hole revealed no unusual markings and the inside diameter was within limits. ## Aircraft - Registration: N466SS (not matched to a registry record) - Reported make and model: Cessna 550 - Category: Airplane - Serial number: 550-0626 - Airframe hours: 3676 - Engines: Pratt & Whitney JT15D-4 2500 lbs thrust turbo fan - Damage: Substantial damage - Flight: Executive/Corporate, Part 91 - Registered owner: Capital Buyers of Delaware, Inc. - Airworthiness certificate: Standard, Transport - Last inspection: Continuous airworthiness, May 1, 2006 - Departed: KCWS, Conway, AR - Destination: KMTH, Marathon, FL - Flight plan: IFR - Airport: KMTH, The Florida Keys Marathon Arpt, runway 25, 5,008 × 100 ft, asphalt ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 34; injuries: none; commercial; airplane ratings: multi-engine land, single-engine land; instrument ratings: airplane; medical: class 1, without waivers/limitations; last flight review July 1, 2006; seat: left; flight hours: 8,475 total, 75 in the last 90 days, 40 in the last 30 days, 2 in the last 24 hours ## Weather - Conditions: Visual (VMC), Day - Wind: 200° at 8 knots - Visibility: 10 statute miles - Lowest ceiling: none - Temperature: 90 °F, dew point 73 °F - Altimeter: 30.03 inHg - Observed at: KMTH ## 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 20060722022549A](https://openairdocs.org/incident/20060722022549A), Jul 22, 2006: Cessna 550, Marathon, FL, Minor damage. (-23) While taxiing at Marathon Airport (mth) enroute to Marathon jet center, the right main landing gear of a Cessna citation N466SS, s/n 550-0626 collapsed.… 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.