# NTSB CEN17LA224: Mckenna SD-1A, N31313, Juneau, WI, June 7, 2017 - Type: NTSB accident investigation - Classification: Accident · No injuries · Limited investigation · Final report - Date: June 7, 2017, 09:30 local (14:30 UTC) - Place: Juneau, WI - Coordinates: 43.426387, -88.703887 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=43.4264&lon=-88.7039&mi=10 - Phase of flight: [Takeoff](https://openairdocs.org/ntsb-phases/300) (OpenAirDocs' grouping) - Defining event: [Takeoff: Flight control sys malf/fail](https://openairdocs.org/ntsb-events/333) - Highest injury: No injuries - Injuries: 1 uninjured - Status: Completed, report June 5, 2018 - Report: Approved by Office Director - NTSB office: Central Region - Parties: Federal Aviation Administration - NTSB case key (mKey): 95361 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=CEN17LA224 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/95361/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=95361 - Page: https://openairdocs.org/ntsb/CEN17LA224 ## Probable cause The pilot’s difficulty controlling the airplane due to his incorrect reinstallation of the wings, which led to a bounced precautionary landing. Contributing to the accident was the failure of the pilot and the mechanic to verify the wings’ angle of incidence. ## Findings NTSB's coded findings; those marked are part of the probable cause. - [Wing structure: flight surfaces (wing)](https://openairdocs.org/ntsb-findings/01035750): Aircraft › Aircraft structures · Incorrect service/maintenance (probable cause); cases with it: [Mckenna SD-1A, 1 case](https://openairdocs.org/ntsb-findings/01035750/cases.md?model=0566127), [All aircraft, 20 cases](https://openairdocs.org/ntsb-findings/01035750/cases.md) - [Maintenance: installation](https://openairdocs.org/ntsb-findings/02062035): Personnel issues › Task performance · Pilot (probable cause); cases with it: [Mckenna SD-1A, 1 case](https://openairdocs.org/ntsb-findings/02062035/cases.md?model=0566127), [All aircraft, 371 cases](https://openairdocs.org/ntsb-findings/02062035/cases.md) - [Maintenance/inspections](https://openairdocs.org/ntsb-findings/01010500): Aircraft › Aircraft handling/service · Incorrect service/maintenance (probable cause); cases with it: [Mckenna SD-1A, 1 case](https://openairdocs.org/ntsb-findings/01010500/cases.md?model=0566127), [All aircraft, 103 cases](https://openairdocs.org/ntsb-findings/01010500/cases.md) - [Inspection: post maintenance inspection](https://openairdocs.org/ntsb-findings/02061515): Personnel issues › Task performance · Pilot (probable cause); cases with it: [Mckenna SD-1A, 1 case](https://openairdocs.org/ntsb-findings/02061515/cases.md?model=0566127), [All aircraft, 57 cases](https://openairdocs.org/ntsb-findings/02061515/cases.md) - [Inspection: post maintenance inspection](https://openairdocs.org/ntsb-findings/02061515): Personnel issues › Task performance · Maintenance personnel (probable cause); cases with it: [Mckenna SD-1A, 1 case](https://openairdocs.org/ntsb-findings/02061515/cases.md?model=0566127), [All aircraft, 57 cases](https://openairdocs.org/ntsb-findings/02061515/cases.md) ## Sequence of events The events NTSB coded, in order, by phase of flight. The defining event best describes what happened. - [Takeoff: Flight control sys malf/fail](https://openairdocs.org/ntsb-events/333) (defining event); cases with it: [Mckenna SD-1A, 1 case](https://openairdocs.org/ntsb-events/333/sequence.md?model=0566127), [All aircraft, 410 cases](https://openairdocs.org/ntsb-events/333/sequence.md) - [Landing-flare/touchdown: Off-field or emergency landing](https://openairdocs.org/ntsb-events/440); cases with it: [Mckenna SD-1A, 1 case](https://openairdocs.org/ntsb-events/440/sequence.md?model=0566127), [All aircraft, 3,365 cases](https://openairdocs.org/ntsb-events/440/sequence.md) - [Landing-flare/touchdown: Abnormal runway contact](https://openairdocs.org/ntsb-events/090); cases with it: [Mckenna SD-1A, 1 case](https://openairdocs.org/ntsb-events/090/sequence.md?model=0566127), [All aircraft, 1,506 cases](https://openairdocs.org/ntsb-events/090/sequence.md) - [Landing-landing roll: Landing gear collapse](https://openairdocs.org/ntsb-events/094); cases with it: [Mckenna SD-1A, 1 case](https://openairdocs.org/ntsb-events/094/sequence.md?model=0566127), [All aircraft, 1,787 cases](https://openairdocs.org/ntsb-events/094/sequence.md) ## Analysis The private pilot stated that, immediately after takeoff, the left wing felt "extremely heavy" and required "an exceptional amount of right aileron" to maintain level flight. During the precautionary landing, the airplane bounced, turned left, and the left main landing gear collapsed. The pilot had recently reinstalled the wings; however, he made no measurements during the reinstallation, and the mechanic who signed off on the condition inspection did not confirm the wings' angle of incidence. Postaccident examination of the airplane revealed that the angle of incidence was incorrect. Given this was the first flight since the reinstallation of the wings, it is likely the incorrect angle of incidence led to the pilot's difficulty controlling the airplane. ## Factual narrative On June 7, 2017, about 0930 central daylight time, an experimental amateur-built SD-1A airplane, N31313, was substantially damaged during a precautionary landing at Dodge County Airport (KUNU), Juneau, Wisconsin. The private-rated pilot was not injured. The personal flight was conducted under the provisions of Title 14 Code of Federal Regulations Part 91. Visual meteorological conditions prevailed and no Federal Aviation Administration (FAA) flight plan had been filed for the flight. The local flight had departed about 0900. According to the pilot, immediately after takeoff the left wing felt "extremely heavy" and required an "exceptional amount of right aileron" to maintain level flight. The pilot was able to fly the airplane around the traffic pattern and perform a precautionary landing on runway 20. During the landing, the airplane bounced, and turned to the right. The left main landing gear collapsed, and the engine mount was substantially damaged. According to the FAA inspector who responded to the accident, the wings had been taken off the airplane prior to its purchase. The pilot purchased the airplane in April of 2016. During the reinstallation of the wings, in April of 2017, the pilot installed the wing bolts where he thought they should go. He did not perform any measurements during this reinstallation. The Airframe and Powerplant Mechanic who signed off on the condition inspection did not confirm the position of the wings and more specifically, the angle of incidence. The accident flight was the first flight after the reinstallation of the wings. Postaccident examination of the airplane revealed that the flight controls were continuous and correct; however, the angle of incidence, on the wings, was incorrect. No other anomalies were noted that would have precluded normal operation. ## Aircraft - Registration: [N31313](https://openairdocs.org/deregistered/N31313-2022-10-01), registration cancelled 2022-10-01, S/N 7, built 1977 (OpenAirDocs) - Reported make and model: MCKENNA SD-1A - Registry model: [Mckenna SD-1A](https://openairdocs.org/model/mckenna-sd-1a) (registry code 0566127) (OpenAirDocs) - Registry engine: [Continental C85 series](https://openairdocs.org/engine/continental-c85-series) (registry code 17008, reciprocating) (OpenAirDocs) - Category: Airplane, amateur-built - Serial number: 7 - Year built: 1977 - Engines: Continental Motors O-200G 100 horsepower reciprocating - Damage: Substantial damage - Flight: Personal, Part 91 - Airworthiness certificate: Special, Experimental (Special) - Last inspection: Condition, April 26, 2017, 197 hours before - Departed: UNU, Juneau, WI - Destination: UNU, Juneau, WI - Airport: UNU, Dodge County Airport, runway 20, 4,027 × 75 ft, asphalt - Equipment: Handheld GPS ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 72; injuries: none; private; airplane ratings: single-engine land; medical: sport pilot; last flight review June 6, 2016; seat: left; restraint: 3-point; flight hours: 388.2 total, 1 in this make and model, 120.5 as pilot in command, 4.6 in the last 90 days, 4.6 in the last 30 days, 0.5 in the last 24 hours ## Weather - Conditions: Visual (VMC), Day - Wind: calm - Visibility: 10 statute miles - Lowest ceiling: none - Temperature: 66 °F, dew point 48 °F - Altimeter: 30.20 inHg - Observed at: KUNU ## 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 20170607006889A](https://openairdocs.org/incident/20170607006889A), Jun 7, 2017: Mckenna SD-1A, Juneau, WI, Substantial damage. Owner purchased an experimental aircraft with the wings, ailerons, flaps, horizontal stab, elevators and rudder removed. The owner reinstalled all parts. An… ## Docket (2 files) The files NTSB released with the investigation on March 6, 2018, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=95361. 755 KB in all. - Pilot/Operator Aircraft Accident Report, NTSB Form 6120.1 (item 1, .PDF, 702 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40460649&FileExtension=.PDF&FileName=Pilot%2FOperator%20Aircraft%20Accident%20Report,%20NTSB%20Form%206120.1-Master.PDF - Record of Conversation - FAA Inspector (item 2, .PDF, 54 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40460650&FileExtension=.PDF&FileName=Record%20of%20Conversation%20-%20FAA%20Inspector-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.