# NTSB CEN18LA112: Piper PA 28, N1722J, Mackinac Island, MI, February 26, 2018 - Type: NTSB accident investigation - Classification: Accident · No injuries · Limited investigation · Final report - Date: February 26, 2018, 07:45 local (12:45 UTC) - Place: Mackinac Island, MI - Coordinates: 45.87611, -84.636947 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=45.8761&lon=-84.6369&mi=10 - Phase of flight: [Approach](https://openairdocs.org/ntsb-phases/500) (OpenAirDocs' grouping) - Defining event: [Approach-VFR pattern final: Part(s) separation from AC](https://openairdocs.org/ntsb-events/338) - Highest injury: No injuries - Injuries: 5 uninjured - Status: Completed, report March 18, 2019 - Report: Approved by Office Director - NTSB office: Central Region - Parties: Federal Aviation Administration - NTSB case key (mKey): 96810 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=CEN18LA112 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/96810/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=96810 - Page: https://openairdocs.org/ntsb/CEN18LA112 ## Probable cause The improper reinstallation of the right main landing gear by maintenance personnel which resulted in the separation of the landing gear and the subsequent abnormal runway contact during the landing. ## Findings NTSB's coded findings; those marked are part of the probable cause. - [Landing gear system: main landing gear](https://openairdocs.org/ntsb-findings/01023210): Aircraft › Aircraft systems · Incorrect service/maintenance (probable cause); cases with it: [Piper PA-28-140, 1 case](https://openairdocs.org/ntsb-findings/01023210/cases.md?model=7102802), [All aircraft, 241 cases](https://openairdocs.org/ntsb-findings/01023210/cases.md) - [Maintenance: installation](https://openairdocs.org/ntsb-findings/02062035): Personnel issues › Task performance · Maintenance personnel (probable cause); cases with it: [Piper PA-28-140, 4 cases](https://openairdocs.org/ntsb-findings/02062035/cases.md?model=7102802), [All aircraft, 371 cases](https://openairdocs.org/ntsb-findings/02062035/cases.md) ## Sequence of events The events NTSB coded, in order, by phase of flight. The defining event best describes what happened. - [Approach-VFR pattern final: Part(s) separation from AC](https://openairdocs.org/ntsb-events/338) (defining event); cases with it: [Piper PA-28-140, 6 cases](https://openairdocs.org/ntsb-events/338/sequence.md?model=7102802), [All aircraft, 563 cases](https://openairdocs.org/ntsb-events/338/sequence.md) - [Landing-flare/touchdown: Dragged wing/rotor/float/other](https://openairdocs.org/ntsb-events/093); cases with it: [Piper PA-28-140, 3 cases](https://openairdocs.org/ntsb-events/093/sequence.md?model=7102802), [All aircraft, 319 cases](https://openairdocs.org/ntsb-events/093/sequence.md) ## Analysis During the final approach for the short cross country flight, the pilot heard a "thud." During the landing flare the pilot suspected a landing gear issue and landed as gently as possible. However, the right wing settled onto the runway and was substantially damaged. A postaccident examination revealed that the landing gear had not been reinstalled correctly during maintenance performed in 2013. Only one of the 8 fasteners required for installation was recovered and it was sheered. The damage to the wing and landing gear was consistent with the improper installation of the fasteners and was not impact related. It is likely that the fasteners were either not installed or not torqued properly during the previous maintenance. Subsequent annual and 100-hour inspections did not detect this discrepancy. ## Factual narrative On February 26, 2018, about 0745 eastern standard time, a Piper PA 28-140 airplane, N1722J, was substantially damaged while landing at the Mackinac Island Airport (KMCD), Mackinac Island, Michigan. The commercial certificated pilot and 4 passengers were not injured. The airplane was owned and operated by Great Lakes Air Inc., under the provisions of Title 14 Code of Federal Regulations Part 135 as a non-scheduled passenger flight. Visual meteorological conditions prevailed and no Federal Aviation Administration (FAA) flight plan was filed for the flight. The flight departed Mackinac County Airport (83D), St Ignace, Michigan, about 0730, and was en route to KMCD. According to written statement submitted by the pilot, the airplane was on final approach when he heard a "thud." During the landing flare, the airplane seemed to settle more than normal. The pilot suspected a landing gear problem or a blown tire and decided to continue with the landing. The pilot landed as "gently" as possible; however, the airplane continued to settle, and the right wing touched the ground. He moved the engine throttle control to idle and maintained directional control with the rudder. A post-accident examination of the airplane, conducted by the responding FAA inspector, revealed substantial damage to the right wing spar. The right main landing gear had separated and was located on the runway, about 200 ft from the arrival threshold. Further examination revealed that the attachment hardware for the right main landing gear was not present in 7 of the 8 mounting holes on the top or bottom mounting brackets. One screw remained in the outboard top bracket of the assembly and was sheered consistent with overload. Several of the holes were elongated consistent with inadequate torque of the fasteners. In addition, fretting was noted at the gear/spar attach point. The sheet metal and mounting surfaces on the wing were otherwise unremarkable. A review of the maintenance records for the airplane revealed that the right main landing gear cylinder was removed and replaced on December 31, 2013. Several annual inspections had taken place since the replacement of the cylinder. The maintenance records indicated that the work was done in accordance with the Piper Maintenance Manual. According to the Piper service manual for the airplane, the upper bracket of the assembly required 4 screws to attach the bracket to the wing. The lower bracket of the assembly requires 4 bolt/nut combinations to attach the bracket to the wing. Each fastener should have been torqued to 50 to 70 inch-pounds at installation. ## Aircraft - Registration: [N1722J](https://openairdocs.org/aircraft/N1722J), registered now, S/N 28-24134, built 1968 (OpenAirDocs) - Reported make and model: PIPER PA 28 (140) - Registry model: [Piper PA-28-140](https://openairdocs.org/model/piper-pa-28-140) (registry code 7102802) (OpenAirDocs) - Registry engine: [Lycoming 0-320 series](https://openairdocs.org/engine/lycoming-0-320-series) (registry code 41508, reciprocating) (OpenAirDocs) - Category: Airplane - Serial number: 28-24134 - Year built: 1968 - Airframe hours: 6344.9 - Engines: Lycoming O-540-E4B5 260 horsepower reciprocating - Damage: Substantial damage - Flight: Part 135 - Operator: Great Lakes Air Inc - Registered owner: Great Lakes Air Inc - Airworthiness certificate: Standard, Normal - Last inspection: 100 hour, January 26, 2018 - Departed: 83D, Saint Ignace, MI - Destination: KMCD, Mackinac Island, MI - Airport: KMCD, Mackinac Island Airport, runway 26, 3,501 × 75 ft, asphalt - Equipment: Stall warning system ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 28; injuries: none; flight instructor, commercial; airplane ratings: single-engine sea, single-engine land, multi-engine land; instrument ratings: airplane; medical: class 1, without waivers/limitations; last flight review January 16, 2018; seat: left; flight hours: 2,621 total, 104 in this make and model, 2,494 as pilot in command, 243 in the last 90 days, 104 in the last 30 days, 0.5 in the last 24 hours ## Weather - Conditions: Visual (VMC), Day - Wind: 250° at 9 knots, gusting 15 - Visibility: 10 statute miles - Lowest ceiling: none - Temperature: 27 °F, dew point 23 °F - Altimeter: 30.04 inHg - Observed at: KMCD, 5 nm away ## Docket (5 files) The files NTSB released with the investigation on June 13, 2018, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=96810. 6.5 MB in all. - Pilot/Operator Aircraft Accident Report, NTSB Form 6120.1 (item 1, .PDF, 5.0 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40463975&FileExtension=.PDF&FileName=Pilot%2FOperator%20Aircraft%20Accident%20Report,%20NTSB%20Form%206120.1-Master.PDF - FAA Inspector Statement (item 2, .PDF, 53 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40463976&FileExtension=.PDF&FileName=FAA%20Inspector%20Statement-Master.PDF - Maintenance Record Excerpt (item 3, .PDF, 396 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40463977&FileExtension=.PDF&FileName=Maintenance%20Record%20Excerpt-Master.PDF - Piper Manual Excerpts (item 4, .PDF, 612 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40463978&FileExtension=.PDF&FileName=Piper%20Manual%20Excerpts-Master.PDF - Accident Report Photographs (item 5, .PDF, 451 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40463979&FileExtension=.PDF&FileName=Accident%20Report%20Photographs-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.