# NTSB CHI07CA028: Cessna 421C, N471BW, Moline, IL, November 26, 2006 - Type: NTSB accident investigation - Classification: Accident · No injuries · Data collection · Final report - Date: November 26, 2006, 17:06 local (23:06 UTC) - Place: Moline, IL - Coordinates: 41.448612, -90.507499 - Nearby events: https://openairdocs.org/map.md?lat=41.4486&lon=-90.5075&mi=10 - Phase of flight: [Landing](https://openairdocs.org/ntsb-phases/550) (OpenAirDocs' grouping) - Highest injury: No injuries - Injuries: 5 uninjured - Status: Completed, report March 26, 2007 - Report: Approved by Office Director - Parties: Federal Aviation Administration - DuPage FSDO - NTSB case key (mKey): 65104 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=CHI07CA028 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/65104/pdf - Page: https://openairdocs.org/ntsb/CHI07CA028 ## Probable cause The incorrect installation of the torque link scissor assembly by maintenance personnel, which resulted in the collapse of the right main landing gear during landing. ## Sequence of events In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf). - Main gear collapsed, landing - flare/touchdown - landing gear,main gear strut scissors - separation (cause) - maintenance,installation - improper, other maintenance personnel (cause) ## Analysis The right main landing gear collapsed during landing flare/touchdown. The pilot reported that the airplane initially touched down on the left main landing gear, followed by the nose and right main landing gears. The pilot stated that when the right main landing gear touched it "didn't feel right or usual." The pilot reported that he advanced engine power, and the airplane became airborne for about 50 feet. The pilot stated that the airplane "bounced onto runway" and the right propeller impacted the runway. The airplane became airborne again, and then "landed hard" for the final time. Inspection of the right main landing gear showed that the upper and lower torque links had separated at the common pivot-point, which allowed the lower strut to rotate within the upper strut. The two torque links are connected by a bolt, nut, bushing, and several washers. The washer that prevents the bolt head and pressed bushing from pulling through the common pivot-point was not installed. The as-installed stack-up remained together, and was attached to the upper torque link. The pressed bushing from the lower torque link was found with the as-installed stack-up. The torque links for the left main landing gear were found correctly assembled. ## Factual narrative The right main landing gear collapsed during landing flare/touchdown. The pilot reported that the airplane initially touched down on the left main landing gear first, followed by the nose and right main landing gears. The pilot stated that when the right main landing gear touched it "didn't feel right or usual." The pilot reported that he advanced engine power and the airplane became airborne for about 50 feet. The pilot stated that the aircraft "bounced onto runway" and the right propeller impacted the runway. The pilot reported that the airplane became airborne again and then "landed hard" for the final time. Inspection of the right main landing gear showed that the upper and lower torque links had separated at the common pivot-point, which allowed the lower strut to rotate within the upper strut. The two torque links are connected by a bolt, nut, bushing, and several washers. The washer that prevents the bolt head and pressed bushing from pulling through the common pivot-point was not installed. The as installed stack-up remained together and was attached to the upper torque link. The pressed bushing from the lower torque link was found with the as installed stack-up. The torque links for the left main landing gear were found correctly assembled. ## Aircraft - Registration: [N471BW](https://openairdocs.org/aircraft/N471BW), registered now, S/N 421C0640 (OpenAirDocs) - Reported make and model: Cessna 421C - Registry model: [Cessna 421C](https://openairdocs.org/model/cessna-421c) (registry code 2076016) (OpenAirDocs) - Category: Airplane - Serial number: 421C0640 - Airframe hours: 4485.1 - Engines: Teledyne Continental GTSIO-520-L 375 horsepower reciprocating - Damage: Substantial damage - Flight: Personal, Part 91 - Registered owner: J & J Air, LLC. - Airworthiness certificate: Standard, Normal - Last inspection: Annual, January 1, 2006 - Departed: BJC, Denver, CO - Destination: MLI, Moline, IL - Flight plan: IFR - Airport: MLI, Quad City International, runway 27, 10,002 × 150 ft, concrete ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 48; injuries: none; private; airplane ratings: single-engine land, multi-engine land; instrument ratings: airplane; medical: class 2, with waivers/limitations; last flight review August 1, 2005; seat: left; flight hours: 874 total, 217 in this make and model, 682 as pilot in command, 20 in the last 90 days, 9 in the last 30 days, 3 in the last 24 hours ## Weather - Conditions: Visual (VMC), Night - Wind: 150° at 4 knots - Visibility: 10 statute miles - Lowest ceiling: none - Temperature: 57 °F, dew point 48 °F - Altimeter: 30.05 inHg - Observed at: MLI ## 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 20061126026799A](https://openairdocs.org/incident/20061126026799A), Nov 26, 2006: Cessna 421C, Moline, IL, Substantial damage. (-23) On November 26, 2006, Cessna model 421C, N471BW, operated by a private pilot, landed on runway 27 at the Quad cites airport (mli), Moline IL. Upon… 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.