NTSB CAROL · Event
Event CHI94LA087
Aircraft involved
Probable cause & findings
the improper maintenance installation (cotter pin) by other maintenance personnel. Factors were main landing gear scissors not safetied properly and extension of landing gear not possible by pilot-in-command (CFI).
Factual narrative
On February 13, 1994, at 1433 central standard time, a Piper PA- 44-180, N190ND, registered to University of North Dakota, and operated by a flight instructor and student, experienced a collapse of the right main landing gear on touchdown at the Grand Forks International Airport, Grand Forks, North Dakota. The airplane sustained substantial damage. The occupants reported no injuries. The 14 CFR Part 91 flight was operating in visual meteorological conditions. No flight plan was on file. The local instructional flight departed Grand Forks, North Dakota, at 1345. The instructor pilot stated that when the landing gear was extended the right main landing gear light began flashing and an unsafe gear warning light was illuminated. Several attempts were made to assure that the landing gear was extended including repeated attempts at normal and emergency gear extension. Maintenance personnel were contacted by radio in an attempt to alleviate the problem. A low pass was made over the airport to attempt to determine if the gear appeared to be extended. The tower reported that the gear appeared to be down. Upon landing the right main landing gear collapsed. A subsequent examination revealed that a cotter pin on the right main landing gear scissors was open and caught a wiring bundle in the wheel well which prevented the down lock from engaging. WHEN THE LANDING GEAR WAS EXTENDED FOR LANDING, THE RIGHT MAIN LANDING GEAR LIGHT BEGAN FLASHING AND AN UNSAFE GEAR WARNING WAS RECEIVED. SEVERAL ATTEMPTS WERE MADE TO ASSURE THE LANDING GEAR WAS EXTENDED INCLUDING REPEATED ATTEMPTS AT NORMAL AND EMERGENCY GEAR EXTENSION. UPON LANDING THE RIGHT MAIN GEAR COLLAPSED. SUBSEQUENT EXAMINATION REVEALED THAT A COTTER PIN ON THE RIGHT MAIN LANDING GEAR SCISSORS HAD BEEN OPEN AND CAUGHT A WIRING BUNDLE IN THE WHEEL WELL WHICH PREVENTED THE DOWN LOCK FROM ENGAGING. Source: NTSB Aviation Accident Database (Pre-2008 Archive) Retrieved: 2026-02-12
Verbatim from NTSB's published report. Source file
NTSB_1994_CHI94LA087.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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