# NTSB WPR17IA189: Cessna 560XL, N503UP, San Jose, CA, August 29, 2017 - Type: NTSB incident investigation - Classification: Incident · No injuries · Class 3 · Incident · Final report - Date: August 28, 2017, 19:00 local (Aug 29, 2017, 02:00 UTC) - Place: San Jose, CA - Coordinates: 37.361946, -121.92666 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=37.3619&lon=-121.9267&mi=10 - Phase of flight: [Landing](https://openairdocs.org/ntsb-phases/550) (OpenAirDocs' grouping) - Defining event: [Landing-landing roll: Landing gear collapse](https://openairdocs.org/ntsb-events/094) - Highest injury: No injuries - Injuries: 5 uninjured - Status: Completed - Report: Approved by Office Director - Investigation class: Class 3 - NTSB office: Western Pacific Region - Parties: Textron Aviation - NTSB case key (mKey): 95904 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=WPR17IA189 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/95904/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=95904 - Page: https://openairdocs.org/ntsb/WPR17IA189 ## Probable cause The mechanic’s incorrect installation of the right main landing gear (MLG) aft trunnion pivot pin, which resulted in the pin separating from the trunnion, the trunnion puncturing the right wing, and the right MLG collapsing. ## Findings NTSB's coded findings; those marked are part of the probable cause. - [Maintenance: scheduled/routine maintenance](https://openairdocs.org/ntsb-findings/02062010): Personnel issues › Task performance · Maintenance personnel (probable cause); cases with it: [All aircraft, 320 cases](https://openairdocs.org/ntsb-findings/02062010/cases.md) - [Misc hardware: fasteners](https://openairdocs.org/ntsb-findings/01071430): Aircraft › Fluids/misc hardware · Incorrect service/maintenance (probable cause); cases with it: [All aircraft, 58 cases](https://openairdocs.org/ntsb-findings/01071430/cases.md) ## Sequence of events The events NTSB coded, in order, by phase of flight. The defining event best describes what happened. - [Landing-landing roll: Landing gear collapse](https://openairdocs.org/ntsb-events/094) (defining event); cases with it: [All aircraft, 1,787 cases](https://openairdocs.org/ntsb-events/094/sequence.md) ## Analysis The pilot and copilot reported that, during the landing roll, the airplane bounced and then veered right and that the pilot then corrected back to the runway centerline. The copilot added that the airplane’s right side seemed to “dip” as it continued to pull right, and the pilot added that the airplane’s right side was lower than its left side, so they assumed that the right main landing gear (MLG) had a flat tire. Subsequently, the pilot was able to taxi the airplane off the runway and park it on a taxiway, and the passengers disembarked without incident. Examination of the airplane revealed that the aft portion of the right MLG trunnion was protruding through the top of the right wing and that the MLG strut and wheel were positioned out and aft in about a 45° angle from their original position. The right MLG trunnion aft pivot pin was not in the trunnion but remained in the trunnion mount in the aft wing spar; it was easily removed from the mount by hand. The retaining bolt used to keep the pivot pin in the trunnion was in place and secured with a nut and cotter pin. Review of the airplane’s maintenance records revealed that the left and right MLG trunnions had been replaced with new trunnions and trunnion pivot pins 8 days before the incident. The mechanic who performed the work stated that, after installing the right MLG aft trunnion pivot pin, it must have shifted aft when he went to install the bolt through the pin. He stated that an “air-pocket” must have developed and pushed the pin back out. He added that the pin looked fully engaged and that he noted no faults during postmaintenance operational checks. Therefore, based on the evidence, it is likely that, after the mechanic installed the right MLG aft trunnion pivot pin, it backed out, which led to the retaining bolt not being installed in the hole in the pivot pin and resulted in the pin separating from the trunnion, the trunnion puncturing the right wing, and the right MLG collapsing. Following the incident, the airplane manufacturer revised the trunnion pivot pin installation procedures in the Airplane Maintenance Manual. The revision included, in part, a step for maintenance personnel to visually check and ensure that the bolt is visible when looking through the pivot pin from the aft side and that, if it is not visible, to remove it, ensure that the pivot pin is fully installed in the trunnion assembly, and reinstall the bolt. ## Factual narrative On August 28, 2017, about 1900 Pacific daylight time, a Cessna 560XL airplane, N503UP, received minor damage to the right wing when it was involved in an incident near San Jose, California. The pilot, copilot, and three passengers were not injured. The airplane was being operated as a Title 14 Code of Federal Regulations Part 135 air taxi flight. The pilot and copilot reported that, during the landing roll, the airplane bounced and then veered right and that the pilot corrected back to the runway centerline. The copilot added that the airplane’s right side seemed to “dip” as it continued to pull right, and the pilot added that the airplane’s right side was lower than its left side, so they assumed that the right main landing gear (MLG) had a flat tire. Subsequently, the pilot was able to taxi the airplane off the runway and park it on a taxiway, and the passengers disembarked without incident. Examination of the airplane revealed that the aft portion of the right MLG trunnion was protruding through the top of the wing and that the MLG strut and wheel were positioned out and aft in about a 45° angle from their original position. The right MLG trunnion aft pivot pin was not in the trunnion but remained in the trunnion mount in the aft wing spar; it was easily removed from the mount by hand. The retaining bolt used to keep the pivot pin in the trunnion was in place and secured with a nut and cotter pin. Review of the airplane’s maintenance records revealed that the left and right MLG trunnions had been replaced with new trunnions and trunnion pivot pins 8 days before the incident. According to the Airplane Maintenance Manual (AMM), when installing the aft MLG trunnion, the pivot pin must be slid forward to align a hole in the trunnion with a hole in the pivot pin, which is then secured in place with a retaining bolt, washer, nut, and cotter pin. The mechanic who performed the work stated that, after installing the right MLG aft trunnion pivot pin, it must have shifted aft when he went to install the bolt through the pin. He stated that an “air-pocket” must have developed and pushed the pin back out. He added that the pin looked fully engaged and that he noted no faults during postmaintenance operational checks. Following the incident, the airplane manufacturer revised the trunnion pivot pin installation procedures in the Airplane Maintenance Manual. The revision included, in part, a step for maintenance personnel to visually check and ensure that the bolt is visible when looking through the pivot pin from the aft side and that, if it is not visible, to remove it, ensure that the pivot pin is fully installed in the trunnion assembly, and reinstall the bolt. ## Aircraft - Registration: N503UP (not matched to a registry record) - Reported make and model: CESSNA 560XL (ENCORE) - Category: Airplane - Serial number: 560-5326 - Year built: 2003 - Engines: P&W CANADA PW545 SER turbo jet; P&W CANADA PW545 SER turbo jet - Damage: Minor damage - Flight: Part 135 - Operator: Wheels Up - Registered owner: Textron Financial Corp - Airworthiness certificate: Standard, Transport - Last inspection: Condition, August 20, 2017 - Departed: TUS, TUCSON, AZ - Destination: SJC, San Jose, CA - Flight plan: IFR - Airport: SJC, Norman Y Mineta San Jose Intl, runway 30L, 11,000 × 150 ft, concrete - Equipment: Auto-pilot, Angle of attack indicator, ADS-B, Stall warning system, Onboard weather, Electronic primary flight display, Electronic multifunction display, Data recorder ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 49; injuries: none; airline transport; airplane ratings: multi-engine land; instrument ratings: airplane; medical: class 1, unknown; seat: left; restraint: 4-point; toxicology performed; flight hours: 14,248 total - Co-pilot; age 49; injuries: none; commercial, airline transport; airplane ratings: single-engine land, multi-engine land; instrument ratings: airplane; medical: class 1, unknown; seat: right; restraint: 4-point; toxicology performed; flight hours: 6,715 total ## Weather - Conditions: Visual (VMC), Day - Wind: 300° at 11 knots - Visibility: 10 statute miles - Lowest ceiling: none - Temperature: 79 °F, dew point 61 °F - Altimeter: 29.79 inHg - Observed at: KSJC ## FAA reports on this event (1) The FAA's own accident and incident reports, matched to the aircraft by N-number and date (OpenAirDocs). - [Incident 20170828017439I](https://openairdocs.org/incident/20170828017439I), Aug 28, 2017: Cessna 560XL, San Jose, CA, Minor damage. On 08/28/2017 at approximately 15:20 local time, N503UP landed at San Jose Airport (sjc). In a statement from the pilot, the aircraft touched down very lightly… ## Docket (10 files) The files NTSB released with the investigation on January 13, 2021, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=95904. 12.5 MB in all. - First officer-written statement (item 1, PDF, 1 page, 77 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=11662932&FileExtension=pdf&FileName=Email-FAA%20FO%20statement_Redacted-Rel.pdf - Pilot-written statement (item 2, PDF, 3 pages, 123 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=11663177&FileExtension=pdf&FileName=Email-FAA%20Pilot%20Statement_Redacted-Rel.pdf - Mechanic, post examination-written statement (item 3, PDF, 1 page, 85 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=11663931&FileExtension=pdf&FileName=Email-Mechanic%20statement%20during%20exam_Redacted-Rel.pdf - Mechanics-written statements (item 4, PDF, 2 pages, 204 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=11662942&FileExtension=pdf&FileName=Statements%20Wayne%20Hieselman%20Patt%20Keahy_Redacted-Rel.pdf - Maintenance logbooks-excerpts (item 5, PDF, 9 pages, 7.5 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=11663676&FileExtension=pdf&FileName=Trunnion%20logbook%20entry_Redacted-Rel.pdf - NTSB email on safety changes (item 6, PDF, 2 pages, 73 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=11663911&FileExtension=pdf&FileName=Email%20WPR17IA189%20Safety%20Suggestion%2002-18-2019_Redacted-Rel.pdf - Maintenance manual excerpts-changes in blue (item 7, PDF, 14 pages, 912 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=11664019&FileExtension=pdf&FileName=Changes%20to%20MM%20in%20blue%20ml-c-560xl-c56xmm598%20(003)-Rel.pdf - Maintenance manual excerpts-additional changes in blue (item 8, PDF, 14 pages, 942 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=11663239&FileExtension=pdf&FileName=560XL%20MM%2032-10-00-2%20Rev%2046%20Main%20Landing%20Gear%20and%20Doors%20-%20Maintenance%20Practices-Rel.pdf - Statement of party representatives to NTSB investigation-textron aviation (item 9, PDF, 1 page, 679 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=11666259&FileExtension=pdf&FileName=Textron%20Avation%20WPR17LA189%20Party%20form_Redacted-Rel.pdf - Photo array-accident site (item 10, PDF, 5 pages, 1.9 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=11663921&FileExtension=pdf&FileName=Accident%20Site-Photo%20Array-Rel.pdf 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.