# NTSB ERA20CA168: Dayton-Wright DH-4, N32517, Bowling Green, KY, May 2, 2020 - Type: NTSB accident investigation - Classification: Accident · No injuries · Class 4 · Data collection · Final report - Date: May 2, 2020, 07:00 local (12:00 UTC) - Place: Bowling Green, KY - Coordinates: 36.964443, -86.419723 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=36.9644&lon=-86.4197&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 4 - Basic report with no Prelim publish - NTSB office: Eastern Region Aviation - Parties: FAA/FSDO - NTSB case key (mKey): 101232 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=ERA20CA168 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/101232/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=101232 - Page: https://openairdocs.org/ntsb/ERA20CA168 ## Probable cause A primary control (aileron) system anomaly that progressively worsened during a test flight that resulted in a loss of control. The reason for the anomaly was not determined due to impact damage. ## Findings NTSB's coded findings; those marked are part of the probable cause. - [Flight control system: aileron control system](https://openairdocs.org/ntsb-findings/01022710): Aircraft › Aircraft systems · Malfunction (probable cause); cases with it: [Dayton-Wright DH-4, 1 case](https://openairdocs.org/ntsb-findings/01022710/cases.md?model=2801921), [All aircraft, 45 cases](https://openairdocs.org/ntsb-findings/01022710/cases.md) - [Not determined](https://openairdocs.org/ntsb-findings/05000000): Not determined › Not determined · Unknown/Not determined (probable cause); cases with it: [Dayton-Wright DH-4, 1 case](https://openairdocs.org/ntsb-findings/05000000/cases.md?model=2801921), [All aircraft, 2,247 cases](https://openairdocs.org/ntsb-findings/05000000/cases.md) - [Performance/control parameters: lateral/bank control](https://openairdocs.org/ntsb-findings/01062023): Aircraft › Aircraft oper/perf/capability · Attain/maintain not possible (probable cause); cases with it: [Dayton-Wright DH-4, 1 case](https://openairdocs.org/ntsb-findings/01062023/cases.md?model=2801921), [All aircraft, 390 cases](https://openairdocs.org/ntsb-findings/01062023/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: [Dayton-Wright DH-4, 1 case](https://openairdocs.org/ntsb-events/333/sequence.md?model=2801921), [All aircraft, 410 cases](https://openairdocs.org/ntsb-events/333/sequence.md) ## Analysis The pilot reported that, during the first flight test of the antique airplane, which was in the process of being restored, he had difficulty controlling the airplane in the roll axis. After takeoff, he noticed that the airplane required some right aileron to keep the wings level. After turning crosswind, the problem worsened, and required that he apply more pressure to the control stick (in the right aileron direction). As he turned downwind, he used nearly full right aileron to maintain control, and the force on the control stick was so high that he was unable to hold it with one hand. When he removed his left hand from the control stick to adjust the throttle, the airplane would roll toward the left. As the airplane approached the base leg, the pilot was unable to keep the wings level; the airplane entered a slip and he was unable to prevent the airplane from turning left. The airplane descended, touched down in the grass to the right of the runway, and came to rest nose down. Examination of the airplane revealed that the aileron control system was continuous. However, due to the airplane damage, the rigging of the aileron system could not be evaluated. The airplane sustained substantial damage to the forward fuselage, lower wing, and horizontal stabilizer. ## Aircraft - Registration: [N32517](https://openairdocs.org/deregistered/N32517-2024-12-28), registration cancelled 2024-12-28, S/N 12459, built 1918 (OpenAirDocs) - Reported make and model: DAYTON-WRIGHT DH-4 - Registry model: [Dayton-Wright DH-4](https://openairdocs.org/model/dayton-wright-dh-4) (registry code 2801921) (OpenAirDocs) - Registry engine: [Liberty V-12](https://openairdocs.org/engine/liberty-v-12) (registry code 38590, reciprocating) (OpenAirDocs) - Category: Airplane - Serial number: 12459 - Year built: 1918 - Airframe hours: 5 - Engines: Lincoln Liberty V12 400 horsepower reciprocating - Damage: Substantial damage - Flight: Flight test, Part 91 - Operator: Saving Liberty Dh4 Llc - Registered owner: Saving Liberty Dh4 Llc - Airworthiness certificate: Special, Special flight (Special); Special, Experimental (Special) - Last inspection: Annual, January 25, 2020, 5 hours before - Departed: BWG, Bowling Green, KY - Destination: BWG, Bowling Green, KY - Airport: BWG, Bowling Green-Warren County Rg, runway 03, 6,501 × 150 ft, grass/turf - Equipment: None ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 73; injuries: none; private; airplane ratings: single-engine land; instrument ratings: airplane; medical: class 3, with waivers/limitations; last flight review January 10, 2019; seat: center; restraint: 4-point; flight hours: 946 total, 309 in this make and model, 946 as pilot in command, 16 in the last 90 days, 3 in the last 30 days, 0.3 in the last 24 hours ## Weather - Conditions: Visual (VMC), Day - Wind: calm - Visibility: 10 statute miles - Lowest ceiling: none - Temperature: 55 °F, dew point 52 °F - Altimeter: 30.12 inHg - Observed at: BWG ## 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 20200502006089A](https://openairdocs.org/incident/20200502006089A), May 2, 2020: Dayton-Wright Co DH-4, Bowling Green, KY, Substantial damage. The aircraft had been performing its first flight since being re-built. The pilot took-off from the grass next to the runway. As the aircraft climbed-out, the… ## Docket (3 files) The files NTSB released with the investigation on June 26, 2020, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=101232. 5.3 MB in all. - Pilot/Operator Aircraft Accident Report, NTSB Form 6120.1 (item 1, .PDF, 4.5 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40484757&FileExtension=.PDF&FileName=Pilot%2FOperator%20Aircraft%20Accident%20Report,%20NTSB%20Form%206120.1-Master.PDF - Memorandum for Record - FAA Inspector (item 2, .PDF, 85 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40484758&FileExtension=.PDF&FileName=Memorandum%20for%20Record%20-%20FAA%20Inspector%20-Master.PDF - Photos (item 3, .PDF, 3 photos, 706 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40484759&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.