NTSB CAROL · Event
Event SEA91LA188
Aircraft involved
Probable cause & findings
PILOT INSTALLED AN IMPROPER 'O' RING WHICH RESTRICTED NORMAL LANDING GEAR EXTENSION AND SUBSEQUENT LOSS OF CONTROL BY THE PILOT.
Factual narrative
THE PILOT OF THE WACO KNF WAS UNABLE TO CONTROL HIS AIRCRAFT WHEN IT PULLED HARD TO THE RIGHT UPON LANDING. THE AIRCRAFT RAN OFF THE SIDE OF THE RUNWAY AND FLIPPED OVER IN THE SOFT DIRT. THE PILOT HAD ADDED AN UNAUTHORIZED O-RING ON TOP OF THE OLEO STRUT SEAL. HE SAID THAT THE SEAL WAS LEAKING AND HE WAS UNABLE TO FIND A REPLACEMENT IN THE LOCAL AREA, WHILE ON A CROSS-COUNTRY FLIGHT. AFTER DEPARTURE THE NEXT MORNING THE STRUT FAILED TO FULLY EXTEND, WHICH CAUSED THE AIRCRAFT TO BECOME DIFFICULT TO CONTROL UPON LANDING. Source: NTSB Aviation Accident Database (Pre-2008 Archive) Retrieved: 2026-02-12
Verbatim from NTSB's published report. Source file
NTSB_1991_SEA91LA188.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, loss of control). Sourced from NASA NTRS, NTSB Safety Studies, FAA CAMI, AOPA Air Safety Institute, Embry-Riddle Scholarly Commons, arXiv, and the Semantic Scholar academic graph.
- Semantic Scholar 2016 · Article (Interacción)
Trajectory Recovery System: Angle of Attack Guidance for Inflight Loss of Control
This paper describes the design and development of an ecological display to aid pilots in the recovery of an In-Flight Loss of Control event due to a Stall (ILOC-S).
- NTSB Aircraft Accident Reports 2010 · Accident report
Loss of Control on Approach — Colgan Air Flight 3407
Colgan Air 3407 / Continental Connection (Q400) Buffalo NY, February 12, 2009 — 50 fatalities. Definitive investigation of the Colgan 3407 stall-stick-pusher crash on approach to Buffalo.
- 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 …
- Embry-Riddle Scholarly Commons 2025 · Journal article (JAAER)
A Scoping Review of Aviation Loss of Control Inflight Research
Loss of control – inflight (LOC-I) contributes to aircraft accidents at unacceptably high rates. Significant industry efforts and research have aimed to improve LOC-I prevention, detection, and recove…
- arXiv 2025 · arXiv preprint
Quadratic Programming Approach to Flight Envelope Protection Using Control Barrier Functions
Ensuring the safe operation of aerospace systems within their prescribed flight envelope is a fundamental requirement for modern flight control systems.
- SKYbrary (Eurocontrol) 2024 · SKYbrary article
Loss of Control In-Flight (LOC-I) — SKYbrary Knowledge Base
SKYbrary comprehensive knowledge-base entry on Loss of Control In-Flight — definitions, contributing factors, accident case studies (Air France 447, Colgan 3407), and prevention strategies.
Browse the full corpus — academia portal ↗