- Date
- July 31, 2011, 08:30 local (15:30 UTC)
- Place
- Yamhill, OR
- Injuries
- 1 uninjured
- Damage
- Substantial damage
- Phase of flight
- Landing
- Aircraft
- N30456Mcdonald Lynn B Avid Flyer Mark IV
- Defining event
- Landing-landing roll: Sys/Comp malf/fail (non-power)
- Weather
- Visual (VMC) · Day
- Status
- Completed · report October 17, 2011
- Report
- Approved by Office Director
- NTSB office
- Western Pacific Region
- Parties
- Federal Aviation Administration
- Case key
- 81358
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 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.
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 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.
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.
Aircraft
- Registration
- N30456
- Reported as
- Mcdonald Lynn B Avid Flyer Mark IV
- Category
- Airplane, amateur-built
- Serial number
- 1279D
- Airframe hours
- 1,541
- Engine
- Bombardier ROTAX (ALL), 65 horsepower, reciprocating
- Damage
- Substantial damage
- Flight
- Personal · Part 91
- Airworthiness certificate
- Special, Experimental (Special)
- Last inspection
- Condition · August 22, 2010 · 14 hours before
- Departed
- S75 · Independence, OR
- Destination
- OR05 · Yamhill, OR
- Airport
- OR05 · Flying M, runway 07, 1,200 × 40 ft, gravel
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
- 76
- Injuries
- None
- Certificate
- Private
- Airplane ratings
- Single-engine land
- Medical
- Class 3, With waivers/limitations
- Last flight review
- June 18, 2011
- Seat
- Left
- Flight hours
- 2,413 total · 1,540 in this make and model · 14 in the last 90 days · 6 in the last 30 days · 0 in the last 24 hours
Weather
- Conditions
- Visual (VMC) · Day
- Wind
- Calm
- Visibility
- 10 statute miles
- Lowest ceiling
- None
- Temperature
- 64 °F
- Altimeter
- 30.04 inHg
Docket · 1
The files NTSB released with the investigation on September 13, 2011, on NTSB’s docket system: statements, records, photos and specialists’ reports. 527 KB in all.