CHARLES D WALKER WALKER CURTISS JN4D
Bowling Green, KY — August 12, 2017
Event Information
| Date | August 12, 2017 |
| Event Type | ACC |
| NTSB Number | GAA17CA488 |
| Event ID | 20170813X81509 |
| Location | Bowling Green, KY |
| Country | USA |
| Coordinates | 36.96695, -86.41917 |
| Airport | BOWLING GREEN-WARREN COUNTY RG |
| Highest Injury | MINR |
Aircraft
| Make | CHARLES D WALKER |
| Model | WALKER CURTISS JN4D |
| Category | AIR |
| FAR Part | 091 |
| Aircraft Damage | SUBS |
Conditions
| Light Condition | DAYL |
| Weather | VMC |
Injuries
| Fatal | 0 |
| Serious | 0 |
| Minor | 1 |
| None | 0 |
| Total Injured | 1 |
Event Location
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.
Full 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.
About This NTSB Record
This aviation event was investigated by the National Transportation Safety Board (NTSB). NTSB investigates all U.S. civil aviation accidents to determine probable cause and issue safety recommendations to prevent future accidents.