Date: 201407
Local time of day: 1801-2400
Location: ZZZ.Airport, US
Flight conditions: VMC
Weather elements / visibility: Windshear; 35
Light: Daylight
Aircraft: Rockwell North American Undifferentiated or Other Model
Operator: Personal
Operating under: Part 91
Flight plan: None
Mission: Ferry / Re-Positioning
Flight phase: Landing
ATC / advisory: Tower ZZZ
Reporter organization: Personal
Reporter function: Pilot Flying; Single Pilot
Reporter qualification: Flight Crew Air Transport Pilot (ATP); Flight Crew Flight Instructor; Flight Crew Instrument; Flight Crew Multiengine
Human factors: Human-Machine Interface; Situational Awareness
Anomaly: Ground Excursion Runway; Inflight Event / Encounter Loss Of Aircraft Control
Detector: Person Flight Crew
When detected: In-flight
Result: Aircraft Aircraft Damaged
Contributing factors: Aircraft; Human Factors
Primary problem: Human Factors

Narrative: The winds were reported as 170 at 11 knots gusts to 16.  The Tower cleared us to land on Runway XX.  I had landed on an intersecting runway several days before; multiple times - with these kinds of winds; in the same tailwheel equipped airplane.  But this time I chose Runway XX just because of the increased safety margin that the reduced crosswind component should provide.  This was my 8th landing in this airplane today; albeit at a different airport. After touchdown on the main wheels I kept the tail in the air to maintain positive contact with the runway under the gusty conditions.  A few seconds into the otherwise normal landing roll; two swerves one right and one left occurred.  The magnitude of the second one was greater than the first.  I responded to each swerve with corrective; rudder inputs but observed myself over-correcting.  A third swerve; again to the right; became uncontrollable and the airplane left the runway pavement at about a 20 degree angle.  This all happened within an estimated 3 seconds.  The tailwheel was still in the air.  We quickly approached several formidable obstacles in the vicinity of the runway; including a parked truck; the airport fence; and a brick building.  I instinctively applied full brakes.  The main wheels dug into the soft dirt; and the aircraft pitched forward until the propeller struck the surface.  The airplane came to a stop about ten feet short of the truck; resting on both main wheels and the engine cowling. A bystander ran over to us to kindly assist in our egress from the tandem cockpit; a challenging act at this awkward pitch attitude.  I had already shut off the magnetos; fuel; and battery master.  We were able to climb out of the airplane without injury.  The fire department showed up a little while later and pronounced the site safe for recovery activities.  Possible causes for the loss of directional control:  1. The winds observed shortly after the incident appeared to be variable in direction; averaging the orientation of the runway centerline; possibly requiring corrections for left and right crosswind components in quick succession.  2. Fatigue and Complacency:  a long flying-day; many successful landings previously accomplished (earlier and in recent weeks - under more challenging conditions) caused me to be less attentive than necessary.  I literally did not see it coming.3. With 12;000 hours of logged tailwheel time; pilot total experience should not be a significant contributing factor.  Recent experience (about 20 hours in type within the last 2 months) was also no factor; in my estimation. A go around immediately initiated would have certainly avoided this mishap.  But the time window to recognize the need for an aborted landing was extremely short.  The lesson: in taildraggers; landings are never administrative.  They should always be treated as a venture into the unknown where anything can happen.




Synopsis: A 12;000 hour tailwheel pilot experiences a runway excursion landing his AT6 and offers some advice.