WPR21LA064
2020-11-03 · El Monte, California, United States · None · 1 aircraft · Status: Completed
Airport EMT
Aircraft involved
Probable cause & findings
A loss of directional control during the landing roll due to an undetermined failure of the tailwheel assembly.
Factual narrative
On November 03, 2020, about 1235 Pacific daylight time, a Stinson 108-3, N6855M, sustained substantial damage when it was involved in an accident in El Monte, California. The flight instructor and the pilot receiving instruction were not injured. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 instructional flight. According to the flight instructor, the purpose of the flight was to provide tailwheel instruction to the private pilot. The pilot receiving instruction performed three full-stop takeoffs and landings from runway 19. During the landing roll following the fourth landing, the airplane began to veer to the left. The instructor assumed the flight controls and applied rudder, but the airplane did not respond. The instructor then applied right brake and the airplane began to turn to the right, but his subsequent application of left rudder produced no response. The airplane continued to turn to the right, and the left wing impacted the ground. The airplane came to rest facing the opposite direction and sustained substantial damage to the left wing and aileron. The airplane was equipped with a Scott 3000 series tailwheel assembly. The design incorporated a swiveling steering arm, that was connected to and controlled by the tailwheel steering yoke through a spring and a tension chain on both the left and right sides. The manufacturer’s instructions called for the spring to be connected directly to the tailwheel yoke, and the chain to be connected to the steering arm with a connector clip. Postaccident examination of the airplane revealed that both of the steering springs and chains had separated from both the tailwheel steering yoke and steering arm assembly and that the tension chain connector clips were connected to the tailwheel steering yoke rather than the steering arm. Both steering springs were located on the runway after the accident. One spring was recovered near the runway 19 centerline about 230 ft beyond the runway threshold, and the second was recovered from the safety area on the left side of the runway about 1,900 ft beyond the threshold. The left and right tension chains were not located. According to the airplane’s maintenance logbooks, the most recent annual inspection was completed 7 flight hours prior to the accident. During an instructional flight in the tailwheel-equipped airplane, the airplane veered left. Despite the instructor’s application of corrective control inputs, the airplane did not respond as expected, ultimately resulting in a ground loop and substantial damage to the left wing. Postaccident examination revealed that both of the airplane’s tailwheel steering springs and tension chains were missing. The springs were found on the runway following the accident, separated from each other by about 1,700 ft. Neither of the chains were located. The manufacturer’s instructions called for the spring to connect directly to the tailwheel yoke, and the chain to connect to the steering arm with a connector clip. Evidence suggests that the spring was instead incorrectly connected directly to the steering arm. This reverse installation, while not in compliance with the maintenance instructions, did not appear to functionally affect the operation of the steering system, and therefore without examination of the missing chains or further examination of the tailwheel assembly, the significance of this finding could not be determined. Source: NTSB Aviation Accident Database Retrieved: 2026-02-12
NTSB Findings
FAA avdata. C = Cause, F = Factor.
- — Aircraft-Aircraft oper/perf/capability-Performance/control parameters-Directional control-Attain/maintain not possible
- — Not determined-Not determined-(general)-(general)-Unknown/Not determined
Verbatim from NTSB's published report. Source file
NTSB_2020_WPR21LA064.txt.
Findings + structured fields enriched from FAA avall.mdb.
Full investigation docket on
data.ntsb.gov ↗.
Search this event elsewhere
External sources are reported, not agency: signal that something happened, not fact about what happened.
- TallyAero Live Wire Aviation press
- NTSB CAROL Agency ↗
- NTSB Docket Agency ↗
- Aviation Safety Network Aviation press ↗
- Kathryn's Report Aviation press ↗
- Aviation Herald Aviation press ↗
- AVweb Aviation press ↗
- Pilots of America Community ↗
- Reddit /r/flying Community ↗
- FlightAware Aviation press ↗
- AOPA accident database Aviation press ↗
- Google News News ↗
- DuckDuckGo News ↗
Related research
Matched on aircraft type or causal vocabulary (stall, maintenance). All research papers
- Embry-Riddle Scholarly Commons 2023 · Conference paper The Value of Strong Partnerships to Build a Successful Aviation Maintenance Career Pathway Program for Transitioning Military Service Members
The aerospace industry is competing with other industries for a qualified workforce, and many of those competing industries are investing heavily in creating workforce development pipelines.
- Embry-Riddle Scholarly Commons 2026 · Journal article (IJAAA) From Reactive to Predictive: A hybrid Trust-Mediated Adoption Framework for Data-Driven Maintenance in Distributed-Authority Aviation Environments
Modern aviation maintenance operates within increasingly data-intensive technological environments, yet the operational integration of predictive maintenance into routine decision-making remains incon…
- NASA NTRS 2026 · Conference Paper Computational Analysis of Steady State Aerodynamics of Transonic Truss-Braced Wing Configuration in Deep Stall
This study presents a computational investigation of steady state aerodynamics of the Subsonic Ultra-Green Aircraft Research (SUGAR) Transonic Truss-Braced Wing (TTBW) configuration over a wide range …
- Semantic Scholar 2026 · Article (Reliability Engineering & System Safety) Understanding human error in military aviation maintenance: The role of Performance shaping factors, cognitive workload and error orientation
- Semantic Scholar 2025 · Article (Applied Sciences) Decision-Making Framework for Aviation Safety in Predictive Maintenance Strategies
The implementation of predictive maintenance (PM) in aviation presents unique challenges due to strict safety requirements, complex operational environments, and regulatory constraints.
- Semantic Scholar 2024 · Article (Defence Science Journal) Modelling of Human Factors in Aviation Maintenance Using HFACS ME Human Factors Analysis and Classification System Maintenance Extension and Bayesian Network
Aircraft maintenance is a complex task involving a skilled human workforce, spare parts, and various other resources. Human factors are an inherent element of the human workforce.