NTSB CAROL · Event
Event CEN17LA091
Aircraft involved
Probable cause & findings
The failure of the landing gear to extend during landing approach due to the interference between the landing gear motor's sector and worm gears.
Factual narrative
On January 18, 2017, at 1630 mountain standard time, a Beech 95-C55, N303QB, experienced a gear-up landing at Blake Field Airport, Delta, Colorado, after the pilot was unable to extend the landing gear using normal and emergency procedures. The airplane sustained substantial damage on impact with the runway surface. The pilot was uninjured. The airplane was registered to and operated by the pilot under 14 Code of Federal Regulations Part 91 as a personal flight that was not operating on a flight plan. Visual meteorological conditions prevailed at the time of the accident. The flight originated from an unknown location. A National Transportation Safety Board (NTSB) Pilot Operator Aircraft Accident/Incident Report, Form 6120.1 was not received from the pilot, who was required to complete and submit the form following email and phone requests by the NTSB Investigator-In-Charge. The pilot was also requested to provide his pilot logbook but that request was not complied with. A post-accident disassembly examination, by a maintenance facility, of the airplane landing gearbox showed that there were three labels attached to the gearbox exterior: a "Beech Aircraft Corporation", part number "95-810017-23 ECH," serial number "94-B-479," a Beechcraft Rebuilt Part," part number "95-810017-23 ECH," serial number "94-B-479," and a "Cruiseair Aviation, Inc." with no part or serial number annotated. The examination revealed that the sector gear was against the stop "so hard" that the bolt for the stop could not be removed until the assembly half screws were removed. The sector gear teeth were partially sheared and were bound with worm gear teeth resulting in interference. Once the gear was turned past the sheared area, the assembly worked "fine." An airplane logbook entry dated November 22, 2014 stated that at a tachometer time of 5,211.40 hours and unknown total time, the landing gear failed to electrically extend and the emergency gear handle was hard to turn for the first two turns. The landing gearbox was sent to "Cruiseair" for "repair/inspection." Gearbox, part number "95-810017-25," serial number "94-13-479," was overhauled and reinstalled. The entry states that there were no defects found when the landing gear was cycled three times, and an emergency landing gear extension was performed. An airplane logbook entry dated July 19, 2016 stated that an airplane total time of 5,239.7 hours, the "landing gear, motor, and actuating linkage" were inspected during an annual inspection. The airplane was placed on jacks and the landing gear was cycled and an emergency landing gear extension was performed with "satisfactory results." The airplane experienced a gear-up landing after the private pilot was unable to extend the landing gear. Postaccident examination of the landing gear motor revealed that the sector gear teeth were partially sheared and were bound with the worm gear teeth, resulting in interference. Once the gear was turned past the sheared area, the assembly functioned with no anomalies. Review of maintenance logs revealed that the most recent annual inspection, which included the landing gear system, was completed about 6 months before the accident with no anomalies noted. Source: NTSB Aviation Accident Database Retrieved: 2026-02-12
NTSB Findings
Hierarchical cause / factor breakdown from the FAA bulk avdata database. Each finding tagged C (Cause) or F (Factor).
- C Aircraft-Aircraft systems-Landing gear system-Gear extension and retract sys-Malfunction - C
Verbatim from NTSB's published report. Source file
NTSB_2017_CEN17LA091.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 (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.
- 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 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.
- Embry-Riddle Scholarly Commons 2024 · Journal article (JAAER)
Low-Resource Automatic Speech Recognition Domain Adaptation – A Case-Study in Aviation Maintenance
With timeliness and efficiency being critical in the aviation maintenance industry, the need has been growing for smart technological solutions that optimize and streamline the different underlying ta…
- Embry-Riddle Scholarly Commons 2024 · Journal article (JAAER)
A New Trajectory in UAV Safety: Leveraging Reinforcement Learning for Distance Maintenance Under Wind Variations
In the field of aviation, safety is a critical cornerstone, and the operation of Unmanned Aerial Vehicle (UAV) systems is deeply connected with this principle.
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