# NTSB CEN17IA155: Cessna 172RG, N6402V, Greeley, CO, March 20, 2017 - Type: NTSB incident investigation - Classification: Incident · No injuries · Incident investigation · Final report - Date: March 20, 2017, 16:46 local (22:46 UTC) - Place: Greeley, CO - Coordinates: 40.426666, -104.636947 - Nearby events: https://openairdocs.org/map.md?lat=40.4267&lon=-104.6369&mi=10 - Phase of flight: [Landing](https://openairdocs.org/ntsb-phases/550) (OpenAirDocs' grouping) - Defining event: [Landing: Landing gear collapse](https://openairdocs.org/ntsb-events/094) - Highest injury: No injuries - Injuries: 1 uninjured - Status: Completed, report September 6, 2017 - Report: Approved by Office Director - NTSB office: Central Region - Parties: Airworthiness Certification Office, Flight Standards District Office - ADs cited in the narratives: [AD 2001-06-06](https://openairdocs.org/ad/2001-06-06) (OpenAirDocs) - SAIBs cited in the narratives: [SAIB CE-17-16](https://openairdocs.org/saib/CE-17-16) (OpenAirDocs) - NTSB case key (mKey): 95008 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=CEN17IA155 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/95008/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=95008 - Page: https://openairdocs.org/ntsb/CEN17IA155 ## Probable cause Failure of the left main landing gear actuator assembly, which resulted in an inability to extend the left main landing gear. ## Findings NTSB's coded findings; those marked are part of the probable cause. - [Landing gear system: landing gear actuator](https://openairdocs.org/ntsb-findings/01023233): Aircraft › Aircraft systems · Failure (probable cause); cases with it: [Cessna 172RG, 3 cases](https://openairdocs.org/ntsb-findings/01023233/cases.md?model=2072438), [All aircraft, 54 cases](https://openairdocs.org/ntsb-findings/01023233/cases.md) ## Sequence of events The events NTSB coded, in order, by phase of flight. The defining event best describes what happened. - [Approach: Miscellaneous/other](https://openairdocs.org/ntsb-events/900); cases with it: [Cessna 172RG, 2 cases](https://openairdocs.org/ntsb-events/900/sequence.md?model=2072438), [All aircraft, 1,556 cases](https://openairdocs.org/ntsb-events/900/sequence.md) - [Landing: Landing gear collapse](https://openairdocs.org/ntsb-events/094) (defining event); cases with it: [Cessna 172RG, 11 cases](https://openairdocs.org/ntsb-events/094/sequence.md?model=2072438), [All aircraft, 1,787 cases](https://openairdocs.org/ntsb-events/094/sequence.md) ## Analysis At the end of a cross-country flight, the commercial pilot noted that the left main landing gear would not extend. He elected to divert to another airport and land with the gear retracted. Postaccident examination revealed that the left main landing gear actuator assembly housing was cracked across the forward attach bolt hole, which resulted in the inability to fully raise or extend the landing gear using either the normal method or the emergency hand pump. Following the incident, the Federal Aviation Administration released a Special Airworthiness Information Bulletin (SAIB) emphasizing the importance of inspecting main landing gear actuator assemblies. This SAIB recommended complying with a supplemental inspection document provided by the manufacturer that prescribed a combination of visual, fluorescent penetrant, and eddy current inspections. The SAIB also included initial and repetitive inspection intervals. ## Factual narrative On March 20, 2016, at 1646 mountain daylight time, a Cessna 172RG airplane, N6402V, landed gear up following a landing gear malfunction at Greeley-Weld County Airport (GXY), Greeley, Colorado. The pilot was not injured and the airplane sustained minor damage. The airplane was registered to and operated by Northern Skies Aviation Inc. under the provisions of 14 Code of Federal Regulations Part 91 as a personal flight. Day visual meteorological conditions existed at the time of the incident. The flight departed at 1330 without a flight plan from Gillette-Campbell County Airport (GCC), Gillette, Wyoming, with a planned destination of Colorado Plains Regional Airport (AKO), Akron, Colorado.According to the pilot, he diverted to GXY after the left landing gear did not extend during arrival to AKO. Following unsuccessful attempts to extend the landing gear, the pilot elected to land gear up at GXY. Examination by Federal Aviation Administration (FAA) inspectors revealed the left main landing gear actuator assembly (part number 9882015-2) housing was cracked across the forward attach bolt hole. The crack allowed the actuator bore to open enough such that the piston would not engage the landing gear pivot sector sufficiently for gear extension. This failure mode resulted in the inability to fully raise or extend the landing gear, either in the normal method or with the emergency hand pump. The airplane's main landing gear was subject to FAA airworthiness directive (AD) 2001-06-06, which required inspection for cracks in landing gear pivot assemblies. This AD was accomplished for the airplane on May 25, 2001. For this incident, a crack was observed in the landing gear actuator assembly, which mates with the landing gear pivot assembly. The failed landing gear actuator assembly was originally installed with the airplane, which had a total time of 6490.1 hours. To address the need for initial and repetitive inspections of the landing gear actuator assembly, the FAA published maintenance alerts in prior years and Textron published service bulletins in 2001 and 2007. Following this incident, the FAA released Special Information Airworthiness Bulletin (SAIB) CE-17-16 for Cessna 172RG, R182, TR182, FR182, and 210/T210/P210-series airplanes. The SAIB emphasized the importance of inspecting main landing gear actuator assemblies and recommended complying with Textron supplemental inspection document (SID) 32-10-01, which directs a combination of visual, fluorescent penetrant, and eddy current inspections, depending on the airplane model. The SAIB included initial and repetitive inspection intervals, as well as recommending an inspection after an unplanned event, such as a hard landing. ## Aircraft - Registration: [N6402V](https://openairdocs.org/aircraft/N6402V), registered now, S/N 172RG0664, built 1980 (OpenAirDocs) - Reported make and model: CESSNA 172RG (NO SERIES) - Registry model: [Cessna 172RG](https://openairdocs.org/model/cessna-172rg) (registry code 2072438) (OpenAirDocs) - Registry engine: [Lycoming O&VO-360 series](https://openairdocs.org/engine/lycoming-o-vo-360-series) (registry code 41514, reciprocating) (OpenAirDocs) - Category: Airplane - Serial number: 172RG0664 - Year built: 1980 - Airframe hours: 6490 - Engines: LYCOMING O&VO-360 SER 180 horsepower reciprocating - Damage: Minor damage - Flight: Personal, Part 91 - Airworthiness certificate: Standard, Normal - Departed: GCC, GILLETTE, WY - Destination: AKO, AKRON, CO - Airport: GXY, Greeley-Weld County, runway 35, 10,000 × 100 ft, asphalt ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 31; injuries: none; commercial; airplane ratings: single-engine land; instrument ratings: airplane; medical: class 2, without waivers/limitations; last flight review March 19, 2017; seat: left; restraint: 3-point; flight hours: 293 total, 41 in this make and model, 193 as pilot in command, 41 in the last 90 days, 0 in the last 30 days, 0 in the last 24 hours ## Weather - Conditions: Visual (VMC), Day - Wind: calm - Visibility: 10 statute miles - Lowest ceiling: none - Temperature: 72 °F, dew point 27 °F - Altimeter: 30.04 inHg - Observed at: KGXY, 1 nm away ## 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 20170320007619I](https://openairdocs.org/incident/20170320007619I), Mar 20, 2017: Cessna 172RG, Greeley, CO, Minor damage. On 03/20/2017 at approximately 1620H MDT, N6402V, a 1980 Cessna model 172RG aircraft landed with landing gear up at the Greeley-Weld county airport (gxy).… ## Docket (4 files) The files NTSB released with the investigation on July 14, 2017, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=95008. 1.3 MB in all. - Pilot/Operator Aircraft Accident Report, NTSB Form 6120.1 (item 1, .PDF, 1.0 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40454260&FileExtension=.PDF&FileName=Pilot%2FOperator%20Aircraft%20Accident%20Report,%20NTSB%20Form%206120.1-Master.PDF - Photo of landing gear actuator housing from accident airplane (item 2, .PDF, 135 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40454261&FileExtension=.PDF&FileName=Photo%20of%20landing%20gear%20actuator%20housing%20from%20accident%20airplane-Master.PDF - Correspondence with FAA (item 3, .PDF, 60 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40454262&FileExtension=.PDF&FileName=Correspondence%20with%20FAA-Master.PDF - FAA SAIB for Landing Gear Actuator Inspection (item 4, .PDF, 126 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40454263&FileExtension=.PDF&FileName=FAA%20SAIB%20for%20Landing%20Gear%20Actuator%20Inspection-Master.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.