# NTSB ERA13LA199: Maxfly Inc/Mckay WM Searey, N914WM, Polk City, FL, April 11, 2013 - Type: NTSB accident investigation - Classification: Accident · Minor injuries · Limited investigation · Final report - Date: April 11, 2013, 15:30 local (19:30 UTC) - Place: Polk City, FL - Coordinates: 28.166666, -81.483886 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=28.1667&lon=-81.4839&mi=10 - Phase of flight: [Initial climb](https://openairdocs.org/ntsb-phases/350) (OpenAirDocs' grouping) - Defining event: [Initial climb: Aircraft structural failure](https://openairdocs.org/ntsb-events/337) - Highest injury: Minor injuries - Injuries: 1 minor, 1 uninjured - Status: Completed, report January 30, 2014 - Report: Approved by Office Director - NTSB office: Eastern Region Aviation - Parties: FAA/FSDO - NTSB case key (mKey): 86635 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=ERA13LA199 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/86635/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=86635 - Page: https://openairdocs.org/ntsb/ERA13LA199 ## Probable cause The improper installation of incorrect attachment hardware by maintenance personnel during an undocumented repair, which resulted in an in-flight structural failure and subsequent loss of aircraft control. Contributing to the accident was the covering of the inspection port during the undocumented repair, which made it impossible for pilots or mechanics to inspect the attachment hardware for problems. ## Findings NTSB's coded findings; those marked are part of the probable cause. - [Wing structure: attach fittings (on wing)](https://openairdocs.org/ntsb-findings/01035740): Aircraft › Aircraft structures · Fatigue/wear/corrosion (probable cause); cases with it: [Maxfly Inc/Mckay WM SEAREY, 1 case](https://openairdocs.org/ntsb-findings/01035740/cases.md?model=05617FP), [All aircraft, 21 cases](https://openairdocs.org/ntsb-findings/01035740/cases.md) - [Wing structure: attach fittings (on wing)](https://openairdocs.org/ntsb-findings/01035740): Aircraft › Aircraft structures · Incorrect service/maintenance (probable cause); cases with it: [Maxfly Inc/Mckay WM SEAREY, 1 case](https://openairdocs.org/ntsb-findings/01035740/cases.md?model=05617FP), [All aircraft, 21 cases](https://openairdocs.org/ntsb-findings/01035740/cases.md) - [Maintenance: replacement](https://openairdocs.org/ntsb-findings/02062020): Personnel issues › Task performance · Maintenance personnel (probable cause); cases with it: [Maxfly Inc/Mckay WM SEAREY, 1 case](https://openairdocs.org/ntsb-findings/02062020/cases.md?model=05617FP), [All aircraft, 70 cases](https://openairdocs.org/ntsb-findings/02062020/cases.md) - [Maintenance: modification/alteration](https://openairdocs.org/ntsb-findings/02062030): Personnel issues › Task performance · Maintenance personnel (probable cause); cases with it: [Maxfly Inc/Mckay WM SEAREY, 1 case](https://openairdocs.org/ntsb-findings/02062030/cases.md?model=05617FP), [All aircraft, 69 cases](https://openairdocs.org/ntsb-findings/02062030/cases.md) ## Sequence of events The events NTSB coded, in order, by phase of flight. The defining event best describes what happened. - [Prior to flight: Aircraft maintenance event](https://openairdocs.org/ntsb-events/040); cases with it: [Maxfly Inc/Mckay WM SEAREY, 1 case](https://openairdocs.org/ntsb-events/040/sequence.md?model=05617FP), [All aircraft, 484 cases](https://openairdocs.org/ntsb-events/040/sequence.md) - [Initial climb: Aircraft structural failure](https://openairdocs.org/ntsb-events/337) (defining event); cases with it: [Maxfly Inc/Mckay WM SEAREY, 1 case](https://openairdocs.org/ntsb-events/337/sequence.md?model=05617FP), [All aircraft, 290 cases](https://openairdocs.org/ntsb-events/337/sequence.md) - [Uncontrolled descent: Collision with terr/obj (non-CFIT) ](https://openairdocs.org/ntsb-events/470); cases with it: [Maxfly Inc/Mckay WM SEAREY, 1 case](https://openairdocs.org/ntsb-events/470/sequence.md?model=05617FP), [All aircraft, 10,189 cases](https://openairdocs.org/ntsb-events/470/sequence.md) ## Analysis The pilot reported that the amateur-built amphibian airplane performed normally during taxi operations and takeoff from the surface of the lake. About 100 feet above the lake, the pilot heard a "loud bang or crashing sound," and the airframe then twisted. The airplane entered an uncontrolled, spiraling descent until it contacted the water. Postaccident examination of the airplane revealed that the right/forward wing strut joint was disconnected from the leading edge and that the attachment bolts were fractured. Further examination revealed that the bolts were installed after the airplane's original assembly and that they were shorter than the prescribed bolts and had been installed opposite the prescribed direction, which likely resulted in fatigue cracking and the eventual shearing of the bolts during the accident flight. Further examination of the wreckage revealed that the inspection port for the right wing strut attachment area had been covered during a previous, undocumented repair, which made it difficult for pilots or maintenance personnel to inspect the attachment hardware. ## Factual narrative On April 11, 2013, about 1530 eastern daylight time, an experimental, amateur-built Searey amphibian airplane, N914WM, was substantially damaged during collision with water after departing controlled flight after takeoff from Lake Agnes, Polk City, Florida. The private pilot/owner reported a minor injuries and the passenger was not injured. Visual meteorological conditions prevailed, and no flight plan was filed for the personal flight, which was conducted under the provisions of 14 Code of Federal Regulations Part 91. The pilot described the performance of the airplane as "customary" and "normal" during taxi and takeoff from the surface of the lake. At an estimated 100 feet above the lake, the pilot heard a "loud bang or crashing sound." The airframe then twisted, and the airplane entered an uncontrolled, spiraling descent to water contact. The pilot held a private pilot certificate with ratings for airplane single-engine land, airplane single-engine sea, and instrument airplane. His most recent Federal Aviation Administration (FAA) second-class medical certificate was issued on October 25, 2011. The pilot reported 3,980 total hours of flight experience, of which 745 hours were in the accident airplane make and model. According to FAA records, the airplane was assembled in 2004 and was equipped with a Rotax 914 engine. The airplane's most recent conditional inspection was conducted on April 6, 2012. At the time of the accident, the airplane had accrued 880 total hours of operation. The current owner was issued an airworthiness certificate for the airplane in 2006, and a review of maintenance records and a pre-buy inspection revealed no previous damage or structural repairs. The airplane was recovered from the lake, and moved to the kit manufacturer's facility where it was examined under the supervision of an FAA aviation safety inspector. Examination of the airplane revealed that the right/forward wing strut attach bolts fractured. Examination of the bolts and their installation revealed that they were not the prescribed hardware, and had been installed at some point after the airplane's original assembly. The bolts were shorter than the prescribed bolts, had been installed opposite the prescribed direction, and had fractured in the threaded portion of the bolt. Further examination of the wreckage revealed that the inspection port for the right wing strut connection was covered during a previous, undocumented repair. The airplane builder stated he had seen photographs of the airplane damaged beneath a hurricane-collapsed hangar. The covering of the inspection port made it impossible for pilots or maintainers to inspect the connection and associated hardware. As a result of the investigation, the kit manufacturer posted four recommendations to owners on the Searey Technical website. The recommendations involved both specific technical and general maintenance practice advice for owners. ## Aircraft - Registration: [N914WM](https://openairdocs.org/deregistered/N914WM-2013-06-04), registration cancelled 2013-06-04, S/N 1DK290C, built 2004 (OpenAirDocs) - Reported make and model: MAXFLY INC/MCKAY WM SEAREY - Registry model: [Maxfly Inc/Mckay WM SEAREY](https://openairdocs.org/model/maxfly-inc-mckay-wm-searey) (registry code 05617FP) (OpenAirDocs) - Registry engine: [Rotax SEE BOMBADIER](https://openairdocs.org/engine/rotax-see-bombadier) (registry code 55555, reciprocating) (OpenAirDocs) - Category: Airplane, amateur-built - Serial number: 1DK290C - Airframe hours: 880 - Engines: ROTAX SEE BOMBADIER 115 horsepower reciprocating - Damage: Substantial damage - Flight: Personal, Part 91 - Operator: Fly Away Inc - Registered owner: Fly Away Inc - Airworthiness certificate: Special, Experimental (Special) - Last inspection: Condition, April 6, 2013 - Departed: FA08, Polk City, FL - Destination: FA08, Polk City, FL - Airport: FA08, Orlampa Incorporated Airport ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 58; injuries: minor; private; airplane ratings: single-engine sea, single-engine land; instrument ratings: airplane; medical: class 2, with waivers/limitations; seat: left; flight hours: 3,980 total, 745 in this make and model, 3,945 as pilot in command, 32 in the last 90 days, 32 in the last 30 days, 11 in the last 24 hours ## Weather - Conditions: Visual (VMC), Day - Wind: 150° at 12 knots, gusting 17 - Visibility: 10 statute miles - Lowest ceiling: none - Temperature: 86 °F, dew point 64 °F - Altimeter: 29.86 inHg - Observed at: KGIF, 7 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). - [Accident 20130411007449A](https://openairdocs.org/incident/20130411007449A), Apr 11, 2013: Maxfly Inc/Mckay Wm SEAREY, Lake Agnes Pol, FL, Destroyed. After a water take off from lake Agnes pilot reported a normal climb to about 100 ft. pilot states airspeed was well above stall and engine was developing full… ## Docket (11 files) The files NTSB released with the investigation on November 26, 2013, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=86635. 8.8 MB in all. - Pilot/Operator Aircraft Accident Report, NTSB Form 6120.1 (item 1, .PDF, 588 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40404181&FileExtension=.PDF&FileName=Pilot%2FOperator%20Aircraft%20Accident%20Report,%20NTSB%20Form%206120.1-Redacted.PDF - Pilot Statement (item 2, .PDF, 23 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40404191&FileExtension=.PDF&FileName=Pilot%20Statement-Redacted.PDF - Wreckage Inspection Statement (item 3, .PDF, 64 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40404193&FileExtension=.PDF&FileName=Wreckage%20Inspection%20Statement-Master.PDF - FAA Inspection Concurrence Statement (item 4, .PDF, 16 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40404194&FileExtension=.PDF&FileName=FAA%20Inspection%20Concurrence%20Statement-Redacted.PDF - Maintenance Records Excerpts (item 5, .PDF, 398 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40404195&FileExtension=.PDF&FileName=Maintenance%20Records%20Excerpts-Redacted.PDF - Maintenance Records Review Statement (FAA) (item 6, .PDF, 80 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40404249&FileExtension=.PDF&FileName=Maintenance%20Records%20Review%20Statement%20(FAA)-Redacted.PDF - Witness Statement (item 7, .PDF, 35 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40404198&FileExtension=.PDF&FileName=Witness%20Statement-Redacted.PDF - Photo 1 - View of Improper (Opposite Direction) Strut Bolt Installation (item 8, .PDF, 1.2 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40404199&FileExtension=.PDF&FileName=Photo%201%20-%20View%20of%20Improper%20(Opposite%20Direction)%20Strut%20Bolt%20Installation-Master.PDF - Photo 2 - View of Proper Strut Bolt Installation (item 9, .PDF, 1.5 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40404202&FileExtension=.PDF&FileName=Photo%202%20-%20View%20of%20Proper%20Strut%20Bolt%20Installation-Master.PDF - Photo 3 - View of Separated Strut Plate (item 10, .PDF, 1.6 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40404211&FileExtension=.PDF&FileName=Photo%203%20-%20View%20of%20Separated%20Strut%20Plate-Master.PDF - Photo 4 - View of Fractured (Improper) Bolts in Threaded Shank Portion (item 11, .PDF, 3.2 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40404214&FileExtension=.PDF&FileName=Photo%204%20-%20View%20of%20Fractured%20(Improper)%20Bolts%20in%20Threaded%20Shank%20Portion-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.