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NTSB accident investigation · Charles D Walker Walker Curtiss JN4D · Bowling Green, KY · August 12, 2017

Accident · Minor injuriesData collectionFinal report
Date
August 12, 2017, 11:00 local (16:00 UTC)
Place
Bowling Green, KY
Injuries
1 minor
Damage
Substantial damage
Phase of flight
Initial climb
Aircraft
N8262Charles D Walker Walker Curtiss JN4D
Defining event
Initial climb: Loss of control in flight
Weather
Visual (VMC) · Day
Status
Completed · report December 15, 2017
Report
Approved by Office Director
NTSB office
General Aviation Accidents
Parties
FAA
FAA report
20170812013359A
Case key
95820

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

On this page

Probable cause

The pilot’s exceedance of the biplane’s critical angle of attack during initial climb, which resulted in an aerodynamic stall and collision with trees.

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.

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 of the experimental, amateur-built biplane reported that, following a normal initial climb, about 100 ft above the ground, the biplane started an uncommanded left turn, followed by a descent. He added that it became apparent that the flightpath was into the tree line, and he "attempted to climb to possibly maintain at least an altitude to clear the trees, but to no avail, nearly stalling." Subsequently, the biplane impacted the trees. The biplane sustained substantial damage to the wings and fuselage. The pilot reported that there were no preaccident mechanical failures or malfunctions with the biplane that would have precluded normal operation. The pilot added that the biplane is "not very stable once in a flying configuration, any air mass (gusts) change can disturb the balance and result in self-induced turns, climbs and descents. These movements have to be countered immediately because of the relative size (small) of control surfaces (rudder, ailerons). And corrections are slow, possibly resulting in loss of altitude. Pilots expect these upsets and become alert for them." The automated weather observation system on the accident airport reported, about the time of the accident, the wind was from 360° at 5 knots. The pilot was departing from runway 03. The calculated density altitude was 1,897 ft.

Factual narrative

The pilot of the experimental, amateur-built, biplane reported that, following a normal initial climb, about 100 ft. above the ground, the biplane started an un-commanded turn to the left, followed by a descent. He added that, it became apparent that the flight path was into the tree line, and he "attempted to climb to possibly maintain at least an altitude to clear the trees, but to no avail, nearly stalling." Subsequently, the biplane impacted the trees. The biplane sustained substantial damage to the wings and fuselage. The pilot reported that there were no preaccident mechanical failures or malfunctions with the biplane that would have precluded normal operation. The pilot added that, the biplane is "not very stable once in a flying configuration, any air mass (gusts) change can disturb the balance and result in self-induced turns, climbs and descents. These movements have to be countered immediately because of the relative size (small) of control surfaces (rudder, ailerons). And corrections are slow, possibly resulting in loss of altitude. Pilots expect these upsets and become alert for them." The automated weather observation system on the accident airport reported, about the time of the accident, the wind was 360° at 5 knots. The pilot was departing on runway 03. The calculated density altitude was 1,897 ft.

Aircraft

Registration
N8262
Reported as
Charles D Walker Walker Curtiss JN4D (NO SERIES)
Category
Airplane, amateur-built
Serial number
WC001
Built
2013
Airframe hours
330
Engine
150 horsepower, reciprocating
Damage
Substantial damage
Flight
Personal · Part 91
Airworthiness certificate
Special, Experimental (Special)
Last inspection
Annual · April 1, 2017
Departed
BWG · Bowling Green, KY
Destination
BWG · Bowling Green, KY
Airport
BWG · Bowling Green-Warren County Rg, runway 03, 6,501 × 150 ft, asphalt
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
75
Injuries
Minor
Certificates
Flight instructor, Airline transport
Airplane ratings
Single-engine sea, Single-engine land, Multi-engine land
Medical
BasicMed
Last flight review
February 17, 2017
Seat
Rear
Restraint
3-point
Flight hours
20,000 total · 60 in this make and model · 17,000 as pilot in command · 25 in the last 90 days · 15 in the last 30 days · 5 in the last 24 hours

Weather

Conditions
Visual (VMC) · Day
Wind
360° at 5 knots
Visibility
9 statute miles
Lowest ceiling
5,000 ft broken
Temperature
79 °F, dew point 73 °F
Altimeter
30.00 inHg
Observed at
KBWG

Docket · 2

The files NTSB released with the investigation on October 23, 2017, on NTSB’s docket system: statements, records, photos and specialists’ reports. 966 KB 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.

Other investigations on N8262 · 1

Matched to the same aircraft by N-number and date.