# NTSB CEN19LA224: Piper PA18, N6983B, Osceola, WI, July 14, 2019 - Type: NTSB accident investigation - Classification: Accident · No injuries · Class 3 · Limited · Final report - Date: July 14, 2019, 13:15 local (18:15 UTC) - Place: Osceola, WI - Coordinates: 45.310001, -92.690002 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=45.3100&lon=-92.6900&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: Approved by Office Director - Investigation class: Class 3 - NTSB office: Central Region - Parties: FAA FSDO, Piper Aircraft - NTSB case key (mKey): 99834 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=CEN19LA224 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/99834/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=99834 - Page: https://openairdocs.org/ntsb/CEN19LA224 ## Probable cause The failure of the right horizontal stabilizer during takeoff, resulting in a loss of control and forced landing. Contributing to the accident was the installation of an unapproved stabilizer frame and failure of maintenance personnel to identify deterioration of the stabilizer during routine maintenance. ## Findings NTSB's coded findings; those marked are part of the probable cause. - [Empennage structure: horizontal stabilizer](https://openairdocs.org/ntsb-findings/01035510): Aircraft › Aircraft structures · Fatigue/wear/corrosion (probable cause); cases with it: [Piper PA-18A 150, 1 case](https://openairdocs.org/ntsb-findings/01035510/cases.md?model=7101837), [All aircraft, 23 cases](https://openairdocs.org/ntsb-findings/01035510/cases.md) - [Maintenance: unauthorized maint/repair](https://openairdocs.org/ntsb-findings/02062040): Personnel issues › Task performance · Maintenance personnel (probable cause); cases with it: [Piper PA-18A 150, 1 case](https://openairdocs.org/ntsb-findings/02062040/cases.md?model=7101837), [All aircraft, 14 cases](https://openairdocs.org/ntsb-findings/02062040/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: [Piper PA-18A 150, 1 case](https://openairdocs.org/ntsb-events/040/sequence.md?model=7101837), [All aircraft, 484 cases](https://openairdocs.org/ntsb-events/040/sequence.md) - [Takeoff: Flight control sys malf/fail](https://openairdocs.org/ntsb-events/333) (defining event); cases with it: [Piper PA-18A 150, 1 case](https://openairdocs.org/ntsb-events/333/sequence.md?model=7101837), [All aircraft, 410 cases](https://openairdocs.org/ntsb-events/333/sequence.md) ## Analysis Upon takeoff, the pilot heard a “bang” and could not control the airplane. The pilot was able to get the wings level before the airplane hit the ground. The airplane bounced, went through a ditch, and came to rest inverted, resulting in substantial damage to the empennage. Examination of the airplane revealed a broken attachment fitting of the right horizontal stabilizer. The fabric covering was removed from the right and left stabilizers. The attachment corner of the right stabilizer frame was fractured. Pitting, multiple broken welds, and corrosion were found around the fracture. The right stabilizer frame had been fabricated and was not a Federal Aviation Adminstration/parts manufacturer approval-approved part. Maintenance records revealed that the stabilizer assembly had been removed for inspection, refurbished, and replaced multiple times. The most recent maintenance was performed about 4 months prior to the accident, when an annual inspection was completed and new sleeves for the forward attachment points were fabricated and installed on the stabilizer assembly. ## Factual narrative On July 14, 2019, about 1315 central daylight time, a Piper PA18-150, N6963B, was substantially damaged when it was involved in an accident near Osceola, Wisconsin. The commercial pilot was not injured. The glider towing flight was conducted under the provisions Title 14 Code of Federal Regulations Part 91. The pilot reported that he had three non-eventful glider tows prior to the accident flight. On the fourth glider tow of the day, the pilot added full power for takeoff and became airborne at 55 mph indicated airspeed. About 5 to 15 feet off the ground, the pilot heard a sudden '"bang," and the nose of the airplane pitched up about 40ºand rolled right about 45º. The aircraft seemed uncontrollable with rudder. The pilot was able to get the wings level before the airplane hit the ground hard. The pilot reduced the power to idle and applied brakes. The airplane skidded between two electric poles, bounced onto a road, went through a ditch, and came to rest inverted. The empennage sustained substantial damage. The glider being towed had released the tow rope and landed uneventfully nearby. Examination of the airplane revealed a broken attachment fitting of the right horizontal stabilizer. The Ceconite fabric covering was removed from the right and left stabilizers. The attachment corner of the right stabilizer frame was fractured. Pitting, multiple broken welds, and corrosion were found around the fracture. The right stabilizer frame had been fabricated and was not a Federal Aviation Adminstration/parts manufacturer approval-approved part. Review of maintenance records revealed that the stabilizer assembly had been removed for inspection, refurbished, and replaced multiple times. The most recent maintenance was performed on March 1, 2019, when an annual inspection was completed and new sleeves for the forward attachment points were fabricated and installed on the stabilizer assembly. ## Aircraft - Registration: [N6983B](https://openairdocs.org/aircraft/N6983B), registered now, S/N 18-5105 (OpenAirDocs) - Reported make and model: Piper PA18 (150) - Registry model: [Piper PA-18A 150](https://openairdocs.org/model/piper-pa-18a-150) (registry code 7101837) (OpenAirDocs) - Registry engine: [Lycoming 0-320 series](https://openairdocs.org/engine/lycoming-0-320-series) (registry code 41508, reciprocating) (OpenAirDocs) - Category: Airplane - Serial number: 18-5105 - Year built: 1956 - Airframe hours: 7040 - Engines: Lycoming O-320 SERIES 180 horsepower reciprocating - Damage: Substantial damage - Flight: Personal, Part 91 - Operator: Red Wing Soaring Association - Registered owner: Red Wing Soaring Association - Airworthiness certificate: Standard, Normal - Last inspection: Annual, March 1, 2019, 51 hours before - Departed: OEO, Osceola, WI - Destination: OEO, Osceola, WI - Airport: OEO, L O Simenstad Muni, runway 10, 2,100 × 75 ft, grass/turf - Equipment: None ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 50; injuries: none; private, commercial; medical: class 2, with waivers/limitations; last flight review November 25, 2018; seat: left; restraint: 4-point; flight hours: 1,000 total, 250 in this make and model, 36 in the last 90 days, 11 in the last 30 days, 1 in the last 24 hours ## Weather - Conditions: Visual (VMC), Day - Wind: 180° at 8 knots - Visibility: 10 statute miles - Lowest ceiling: 3,800 ft broken - Temperature: 84 °F, dew point 72 °F - Altimeter: 30.05 inHg - Observed at: OEO ## 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 20190714011749A](https://openairdocs.org/incident/20190714011749A), Jul 14, 2019: Piper PA-18A 150, Osceola, WI, Substantial damage. Tow plane pilot (tpp)stated that the accident flight was the 5th flight of the day, the tow rope was attached to his plane from a previous flight, he dragged… ## Other investigations on N6983B (1) 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. - [NTSB FTW69D0539](https://openairdocs.org/ntsb/FTW69D0539), May 19, 1969: Piper PA-18A (N6983B), Sonora, TX, substantial damage ## Docket (3 files) The files NTSB released with the investigation on January 26, 2022, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=99834. 13.8 MB in all. - NTSB form 6120 pilot operator report CEN19LA224 (item 1, PDF, 9 pages, 974 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=13057948&FileExtension=pdf&FileName=NTSB%20Form%206120%20Pilot%20Operator%20Report%20CEN19LA224_Redacted-Rel.pdf - Memorandum for the record stabilizer examination findings CEN19LA224 (item 2, PDF, 3 pages, 701 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=13058488&FileExtension=pdf&FileName=Memorandum%20for%20the%20Record%20Stabilizer%20Examination%20Findings%20CEN19LA224_Redacted-Rel.pdf - Memorandum for the record maintenance logbook review CEN19LA224 (item 3, PDF, 9 pages, 12.1 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=13058794&FileExtension=pdf&FileName=Memorandum%20for%20the%20Record%20Maintenance%20Logbook%20Review%20CEN19LA224_Redacted-Rel.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.