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WPR11CA358

2011-07-31 · Yamhill, Oregon, United States · None · 1 aircraft · Status: Completed

Airport OR05

Current FAA registration · N30456

Make / Model
MCDONALD LYNN B AVID FLYER MARK IV
Year of manufacture
1994 · 17 years old at event
Engine
BOMBARDIER ROTAX (ALL)
Seats / Engines
2 seats · 1 engine
Last airworthiness date
20250917
ADS-B equipped
Yes — Mode-S A33154

Source: FAA Aircraft Registry (releasable master file).

Aircraft involved

Probable cause & findings

The pilot’s loss of directional control during landing rollout due to an unlocked tail wheel that was caused by a degradation of the tailwheel assembly mounting angle.

Factual narrative

The pilot reported that his approach to, and landing on, the private airstrip in his homebuilt, experimental, conventional gear airplane were normal. During rollout in the calm wind condition, the airplane began an uncommanded right turn. The pilot stated that he attempted to correct his loss of directional control by application of rudder and engine power. However, the tail wheel had unlocked and was evidently in a castoring mode. Despite his efforts to straighten the airplane’s path, the airplane veered off the runway. It rolled over brush and went into a ditch. During the impact sequence one propeller blade broke, and the left wingtip and a wing rib were broken. The pilot reported that he built and maintained the experimental airplane. He opined that the accident could have been prevented had the angle of the tail wheel assembly been correct. After years of use, the tail wheel spring-to-empennage attachment assembly flattened. The incorrect angle altered the tail wheel’s pivot point. This event, combined with the vibration induced during rollout on the gravel runway, allowed the tail wheel to unlock. The pilot reported that his approach to, and landing on, the private airstrip in his amateur-built, experimental, conventional gear airplane were normal. During rollout in the calm wind condition, the airplane began an uncommanded right turn. The pilot attempted to correct his loss of directional control by application of rudder and engine power. However, the tail wheel had unlocked and was evidently in a castoring mode. Despite his efforts to straighten the airplane’s path, the airplane veered off the runway and impacted a ditch. During the impact sequence one propeller blade broke, and the left wingtip and a wing rib were broken. The pilot reported that he built and maintained the experimental airplane. He opined that the accident could have been prevented had the angle of the tail wheel assembly been correct. After years of use, the tail wheel spring-to-empennage attachment assembly flattened. The incorrect angle altered the tail wheel’s pivot point. This event, combined with the vibration induced during rollout on the gravel runway, allowed the tail wheel to unlock. Source: NTSB Aviation Accident Database Retrieved: 2026-02-12

NTSB Findings

FAA avdata. C = Cause, F = Factor.

  • C Aircraft-Aircraft systems-Landing gear system-Nose/tail landing gear-Damaged/degraded - C
  • C Aircraft-Aircraft oper/perf/capability-Performance/control parameters-Directional control-Not attained/maintained - C
  • — Environmental issues-Physical environment-Runway/land/takeoff/taxi surfa-(general)-Contributed to outcome

Verbatim from NTSB's published report. Source file NTSB_2011_WPR11CA358.txt. Findings + structured fields enriched from FAA avall.mdb. Full investigation docket on data.ntsb.gov ↗.