# NTSB CEN16LA354: North American Navion, N91488, Monett, MO, August 29, 2016 - Type: NTSB accident investigation - Classification: Accident · No injuries · Limited investigation · Final report - Date: August 29, 2016, 09:30 local (14:30 UTC) - Place: Monett, MO - Coordinates: 36.906112, -94.012779 - Nearby events: https://openairdocs.org/map.md?lat=36.9061&lon=-94.0128&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: 1 uninjured - Status: Completed, report May 1, 2017 - Report: Approved by Office Director - NTSB office: Central Region - Parties: FAA FSDO - NTSB case key (mKey): 93955 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=CEN16LA354 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/93955/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=93955 - Page: https://openairdocs.org/ntsb/CEN16LA354 ## Probable cause Maintenance personnel’s failure to properly rig the right main landing gear locking mechanism, which resulted in a gear collapse during landing. ## Findings NTSB's coded findings; those marked are part of the probable cause. - [Landing gear system: gear extension and retract sys](https://openairdocs.org/ntsb-findings/01023230): Aircraft › Aircraft systems · Incorrect service/maintenance (probable cause); cases with it: [North American NAVION, 1 case](https://openairdocs.org/ntsb-findings/01023230/cases.md?model=6150130), [All aircraft, 416 cases](https://openairdocs.org/ntsb-findings/01023230/cases.md) - [Maintenance](https://openairdocs.org/ntsb-findings/02062000): Personnel issues › Task performance · Maintenance personnel (probable cause); cases with it: [North American NAVION, 1 case](https://openairdocs.org/ntsb-findings/02062000/cases.md?model=6150130), [All aircraft, 143 cases](https://openairdocs.org/ntsb-findings/02062000/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: [North American NAVION, 1 case](https://openairdocs.org/ntsb-events/094/sequence.md?model=6150130), [All aircraft, 1,787 cases](https://openairdocs.org/ntsb-events/094/sequence.md) - [Landing-landing roll: Loss of control on ground](https://openairdocs.org/ntsb-events/230); cases with it: [North American NAVION, 3 cases](https://openairdocs.org/ntsb-events/230/sequence.md?model=6150130), [All aircraft, 4,585 cases](https://openairdocs.org/ntsb-events/230/sequence.md) - [Landing-landing roll: Runway excursion](https://openairdocs.org/ntsb-events/300); cases with it: [North American NAVION, 2 cases](https://openairdocs.org/ntsb-events/300/sequence.md?model=6150130), [All aircraft, 3,643 cases](https://openairdocs.org/ntsb-events/300/sequence.md) - [Landing-landing roll: Collision with terr/obj (non-CFIT) ](https://openairdocs.org/ntsb-events/470); cases with it: [North American NAVION, 3 cases](https://openairdocs.org/ntsb-events/470/sequence.md?model=6150130), [All aircraft, 10,189 cases](https://openairdocs.org/ntsb-events/470/sequence.md) ## Analysis The commercial pilot stated that, during the landing roll following a normal landing, the airplane began pulling to the right. The airplane departed the right side of the runway and traveled down an embankment and through a barbed wire fence. When the pilot inspected the airplane, he noted that the right main landing gear (MLG) had collapsed. An examination of the landing gear found that the locking mechanism had been improperly rigged. Several weeks before the accident, the airplane's right MLG was damaged in an incident and had been replaced with a serviceable unit. A review of maintenance records noted that a gear retraction test was conducted after the replacement and described as satisfactory. It is likely that during this maintenance, the landing gear was improperly rigged, which resulted in its collapse on the accident flight. ## Factual narrative On August 29, 2016, about 0930 central daylight time, a North American Navion airplane, N91488, departed off the side of the runway at the Monett Regional Airport (KHFJ), Monett, Missouri. The pilot was not injured and the airplane was substantially damaged. The airplane was registered to and operated by a private individual under the provisions of 14 Code of Federal Regulations Part 91 as a personal flight. Visual meteorological conditions prevailed for the flight, which operated without a flight plan. The flight originated from the Gimlin Airport (18MO), Ozark, Missouri, and was landing at KHFJ.According to the pilot, he landed the airplane on runway 18 at KHFJ about 0930. Weather was clear and he estimated the wind at 120° at 4 knots. Following a normal approached and landing, he noticed the airplane's right wing was lower than the left wing, and the airplane began a pull to the right. The airplane departed the right side of the runway, went down an embankment and run through a barbed wire fence. When the pilot inspected the airplane, he noted that the right main landing gear (MLG) had collapsed. During recovery of the airplane, the airplane was lifted and the right MLG was extended manually and locked. The airplane was examined by inspectors from the Federal Aviation Administration. A landing gear swing test was conducted and the landing gear had been improperly rigged. A review of the airplane's history revealed that several weeks prior to the accident, the airplane's right MLG scissor was damaged during a high speed turn. A review of maintenance records revealed that on July 22, 2016, the airplane's right MLG scissor was replaced with a serviceable unit. A gear retraction test was conducted and described as satisfactory. ## Aircraft - Registration: [N91488](https://openairdocs.org/deregistered/N91488-2018-08-09), registration cancelled 2018-08-09, S/N NAV-4-119, built 1946 (OpenAirDocs) - Reported make and model: NORTH AMERICAN NAVION (A) - Registry model: [North American NAVION](https://openairdocs.org/model/north-american-navion) (registry code 6150130) (OpenAirDocs) - Registry engine: [Continental E185 series](https://openairdocs.org/engine/continental-e185-series) (registry code 17014, reciprocating) (OpenAirDocs) - Category: Airplane - Serial number: NAV-4-119 - Year built: 1946 - Airframe hours: 1611 - Engines: Continental IO-520-BA 285 horsepower reciprocating - Damage: Substantial damage - Flight: Personal, Part 91 - Airworthiness certificate: Standard, Utility; Standard, Normal - Last inspection: Annual, October 26, 2015, 40 hours before - Departed: 18MO, OZARK, MO - Destination: HFJ, Monett, MO - Airport: HFJ, Monett Rgnl, runway 18, 5,000 × 75 ft, concrete ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 70; injuries: none; commercial; airplane ratings: single-engine land; instrument ratings: airplane; medical: class 3, with waivers/limitations; seat: left ## Weather - Conditions: Visual (VMC), Day - Wind: 120° at 5 knots - Visibility: 10 statute miles - Lowest ceiling: none - Temperature: 81 °F, dew point 72 °F - Altimeter: 30.19 inHg - Observed at: KHFJ ## 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 20160829015439A](https://openairdocs.org/incident/20160829015439A), Aug 29, 2016: North American NAVION, Monett, MO, Substantial damage. Upon touchdown on runway 18 at khfj, the pilot noticed the right wing lower than the left wing. The aircraft then started pulling to the right and departed the… ## Docket (3 files) The files NTSB released with the investigation on March 29, 2017, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=93955. 1.2 MB in all. - Pilot's statement (item 1, .PDF, 81 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40450468&FileExtension=.PDF&FileName=Pilot%27s%20statement-Master.PDF - Record of Conversation Plum (item 2, .PDF, 87 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40450469&FileExtension=.PDF&FileName=Record%20of%20Conversation%20Plum-Master.PDF - Photos (item 3, .PDF, 1.0 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40450470&FileExtension=.PDF&FileName=Photos-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.