ERA20CA168

NTSB accident investigation · Dayton-Wright DH-4 · Bowling Green, KY · May 2, 2020

Accident · No injuriesClass 4 · Data collectionFinal report
Date
May 2, 2020, 07:00 local (12:00 UTC)
Place
Bowling Green, KY
Injuries
1 uninjured
Damage
Substantial damage
Phase of flight
Takeoff
Aircraft
N32517Dayton-Wright DH-4
Defining event
Takeoff: Flight control sys malf/fail
Weather
Visual (VMC) · Day
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
FAA report
20200502006089A
Case key
101232

From the NTSB’s public API. By law, NTSB reports can’t be used as evidence in lawsuits over the accident.

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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 · 3

NTSB’s coded findings. Those marked are part of the probable cause; the rest are factors or other findings. Under each, the cases with the same finding.

Not determinedNot determined › Not determined · Unknown/Not determinedDayton-Wright DH-4: 1 caseAll aircraft: 2,247 casesProbable cause
Performance/control parameters: lateral/bank controlAircraft › Aircraft oper/perf/capability · Attain/maintain not possibleDayton-Wright DH-4: 1 caseAll aircraft: 390 casesProbable cause

Sequence of events

The events NTSB coded, in order, by phase of flight. The defining event is the one that best describes the accident. Under each, the cases with the same event anywhere in their sequence.

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
Reported as
Dayton-Wright DH-4
Category
Airplane
Serial number
12459
Built
1918
Airframe hours
5
Engine
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

Matched to the registry by N-number and the event date; the registry’s history has gaps, so older matches can be wrong. Compare the reported make and model.

Flight crew

As NTSB recorded them. NTSB leaves out names.

Role
Pilot
Age
73
Injuries
None
Certificate
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

Docket · 3

The files NTSB released with the investigation on June 26, 2020, on NTSB’s docket system: statements, records, photos and specialists’ reports. 5.3 MB in all.

FAA reports on this event · 1

The FAA’s own accident and incident reports, matched to the aircraft by N-number and date.