NTSB CAROL · Event
Event LAX04LA230
Registry · N121JR
FAA Aircraft Registry record.
Make / Model
CESSNA T210M
Year of manufacture
1977 · 27 years old at event
Engine
CONT MOTOR TSIO-520 SER (300 hp)
Seats / Engines
6 seats · 1 engine
Last airworthiness date
19770207
ADS-B equipped
Yes — Mode-S A05841
Registrant of record
KLOTZ GEOFFREY B
Source: FAA Aircraft Registry (releasable master file).
Aircraft involved
Probable cause & findings
Maintenance personnel's improper installation and servicing of a retaining ring, which resulted in the failure of the landing gear door actuator and failure of the landing gear extension system during landing.
Factual narrative
On May 30, 2004, at 1355 Pacific daylight time, a Cessna T210M single-engine airplane, N121JR, landed with the main landing gear retracted at the Charles M. Schulz - Sonoma County Airport (STS), Santa Rosa, California. The pilot owned and operated the airplane under the provisions of 14 CFR Part 91 as a personal flight. The private pilot and five passengers were not injured; the airplane sustained substantial damage. The flight departed Upper Lake, California, approximately 1300, and was terminating when the event occurred. Visual meteorological conditions prevailed, and a flight plan had not been filed. During a telephone interview with the pilot, he stated that he landed at Upper Lake earlier in the day. Prior to takeoff, the pilot conducted a walk around inspection of the airplane and noted no anomalies. Upon arriving at STS, the pilot noticed that when he went to extend the landing gear, the hydraulic power pack motor kept running and the landing gear down-and-locked light did not illuminate. The pilot looked at the reservoir and noticed that there was plenty of hydraulic fluid in the tank. He attempted to retract and lower the landing gear again, to no avail. He then performed the Pilot Operating Handbook's recommended procedures for landing gear malfunctions, also to no avail. The pilot contacted the STS control tower and notified them of the situation. Another aircraft flew by the accident airplane, and examined the landing gear. The pilot of the other aircraft notified the accident pilot that the nose landing gear was extended, but the main landing gear remained only partially extended. The pilot briefed his passengers of the ensuing landing scenario. He performed a soft-field landing on runway 19 with crash/fire rescue personnel standing by. Upon touchdown, the airplane tilted and veered to the left. The airplane continued to the left where it departed the runway and impacted a taxiway sign before coming to rest upright. According to the pilot, the hydraulic power pack motor was replaced with a repaired motor 3 months prior to the accident. In addition, approximately 1.5 weeks prior to the accident, the right main landing gear door actuator was repaired due to a leaking o-ring. According to a mechanic located at the STS airport, the left wing, horizontal stabilizer, and elevator sustained structural damage. The mechanic noted that the right main landing gear door actuator had come undone, and hydraulic fluid was along the right side of the airframe aft of the door. He also noticed that the retaining snap-ring that holds the actuator together had been installed improperly (the rounded, or pressed, side of the snap-ring was facing away from the actuator piston). A work order, dated May 11, 2004, indicated that at an aircraft total time of 4,492.3 hours, the "starboard main gear door actuator" was leaking. The same work order indicated that mechanics "removed the right gear door actuator. Found o-rings worn. R&R [Removed and Replaced] with new o-rings. Reinstalled actuator with new locknuts. Ops check good, leak check good." The airplane accumulated 10.7 hours since the right main landing gear door actuator work. The airplane landed with the main landing gear retracted after a main landing gear door actuator failure. The pilot attempted to extend the landing gear for landing, and stated that the main landing gear would not extend, and the landing gear down-and-locked light did not illuminate. The pilot noted that the hydraulic motor continued running and that there was plenty of hydraulic fluid in the reservoir. After performing all of the recommended emergency procedures for landing gear malfunctions to no avail, the pilot landed with the nose landing gear extended and the main landing gear only partially extended. Upon landing, the airplane tilted and drifted to the left of the runway, where it impacted a sign. Post-accident examination of the landing gear revealed the right main landing gear door actuator failed, and the retaining clip was installed improperly. The failed landing gear door actuator was worked on 10.7 hours prior to the accident. Source: NTSB Aviation Accident Database (Pre-2008 Archive) Retrieved: 2026-02-12
Verbatim from NTSB's published report. Source file
NTSB_2004_LAX04LA230.txt.
Findings + structured fields enriched from FAA avall.mdb.
Full investigation docket on
data.ntsb.gov ↗.
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Related research
What the literature says.
Academic papers and agency reports matching this event's aircraft type or causal vocabulary (icing, stall, maintenance). Sourced from NASA NTRS, NTSB Safety Studies, FAA CAMI, AOPA Air Safety Institute, Embry-Riddle Scholarly Commons, arXiv, and the Semantic Scholar academic graph.
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- Embry-Riddle Scholarly Commons 2023 · Conference paper
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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.
- arXiv 2022 · arXiv preprint
Enhanced Prediction of Three-dimensional Finite Iced Wing Separated Flow Near Stall
Icing on three-dimensional wings causes severe flow separation near stall. Standard improved delayed detached eddy simulation (IDDES) is unable to correctly predict the separating reattaching flow due…
- NASA NTRS 2019 · Contractor Report (CR)
An Evaluation of an Analytical Simulation of an Airplane with Tailplane Icing by Comparison to Flight Data
This report presents the assessment of an analytical tool developed as part of the NASA/FAA Tailplane Icing Program. The analytical tool is a specialized simulation program called TAILSM4 which was de…
- NASA NTRS 2019 · Technical Publication (TP)
NASA/FAA Tailplane Icing Program: Flight Test Report
This report presents results from research flights that explored the characteristics of an ice-contaminated tailplane using various simulated ice shapes attached to the leading edge of the horizontal …
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