NTSB CAROL · Event
Event ANC19LA039
Aircraft involved
Probable cause & findings
A ductile overstress fracture failure of the right main landing gear bell crank assembly pivot bolt, which resulted in a collapse of the right main landing gear.
Factual narrative
On July 22, 2019, about 1147 mountain daylight time, a Cessna 402B airplane, N7947Q, sustained substantial damage when it was involved in an accident near Boise, Idaho. The two pilots and the FAA observer were uninjured. The airplane was operated under Title 14 Code of Federal Regulations (CFR) Part 91, in accordance with a Part 135.297 instrument proficiency check and a Part 135.399 check airman observation flight. The first pilot, who was the operator's director of operations, reported that he was receiving an instrument proficiency check from the second pilot, the operator's chief pilot; with an FAA aviation safety inspector in the passenger cabin observing the check ride for the purposes of a check airman observation flight. The first pilot stated that, after completing a series of required flight maneuvers, they returned to the departure airport, and the airplane was subsequently cleared to land. During the landing approach, he selected the landing gear selector switch to the down position, which was followed by "three greens," indicating that the landing gear was down, locked, and safe for landing. He noted that all three occupants verified and verbally confirmed that the landing gear was "down and locked." The first pilot stated that, after an uneventful landing, the airplane continued down the runway as the airplane decelerated. When the pilot started a left turn to exit the runway, the right main landing gear collapsed, and the right wing impacted the ground, sustaining substantial damage. A postaccident examination of the landing gear system revealed that the right main landing gear assembly bell crank pivot bolt (p/n NAS464P4-26) had sheared and displayed features consistent with a ductile overstress fracture failure. Figure 1, from the applicable parts catalogue, depicts the main landing gear retraction linkage. The affected bolt from the accident airplane is labeled as #29. Figure 1. Cessna 402 Main Landing Gear Retraction Linkage Installation The pilot reported that, during the landing approach, he selected the landing gear selector switch to the down position, which was followed by "three greens," indicating that the landing gear was down, locked, and safe for landing. He noted that all three occupants verified and verbally confirmed that the landing gear was "down and locked." The airplane landed uneventfully, but as the pilot started a left turn onto the taxiway, the right main landing gear collapsed, and the right wing struck the ground, sustaining substantial damage. A postaccident examination of the landing gear system revealed that the right main landing gear assembly bell crank pivot bolt had sheared and displayed features consistent with a ductile overstress fracture from shear loading. 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).
- — Aircraft-Aircraft systems-Landing gear system-Main landing gear attach sec-Failure
Verbatim from NTSB's published report. Source file
NTSB_2019_ANC19LA039.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). Sourced from NASA NTRS, NTSB Safety Studies, FAA CAMI, AOPA Air Safety Institute, Embry-Riddle Scholarly Commons, arXiv, and the Semantic Scholar academic graph.
- 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 …
- arXiv 2023 · arXiv preprint
Automating Bird Diverter Installation through Multi-Aerial Robots and Signal Temporal Logic Specifications
This paper tackles the task assignment and trajectory generation problem for bird diverter installation using a fleet of multi-rotors.
- arXiv 2023 · arXiv preprint
Variation of Critical Crystallization Pressure for the Formation of Square Ice in Graphene Nanocapillaries
Two-dimensional square ice in graphene nanocapillaries at room temperature is a fascinating phenomenon and has been confirmed experimentally.
- arXiv 2023 · arXiv preprint
Polycrystallinity enhances stress build-up around ice
Damage caused by freezing wet, porous materials is a widespread problem, but is hard to predict or control. Here, we show that polycrystallinity makes a great difference to the stress build-up process…
- 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…
- Embry-Riddle Scholarly Commons 2021 · Journal article (JAAER)
Analysis on the Negative Emotional, Physiological, and Cognitive Responses Elicited from of the Activation of a Stall Alarm
Failing to identify an aerodynamic stall can lead to the inability of an aircraft to sustain flight. To warn pilots of an impending or fully-developed stall, many aircraft have safety devices installe…
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