NTSB CAROL · Event
Event ERA21LA350
Aircraft involved
Probable cause & findings
The pilot was unable to stop the airplane during the landing for reasons which could not be determined, resulting in a runway excursion.
Factual narrative
On September 3, 2021, about 1244 eastern daylight time, a Raytheon Aircraft Company 390, N351CW, was substantially damaged when it was involved in an accident at Naples Municipal Airport (APF), Naples, Florida. The pilot and three passengers were not injured. The airplane was operated as a Title 14 Code of Federal Regulations Part 135 on-demand flight. According to the pilot, the takeoff and en route portions of the flight were uneventful. During landing, he applied normal braking and the airplane started to slow down. Suddenly the brakes “faded away,” and he was unable to stop the airplane. He further described that he applied full braking pressure and the pedals were operating as they should, but the airplane was not stopping. He added that every few feet the brakes would grab, lock-up for a few feet, and then release. The brakes grabbed several times during the landing roll but were not slowing the airplane down. The airplane overran the end of the runway, and the pilot steered the airplane into the grass and away from a jet blast fence. A Federal Aviation Administration inspector who examined the airplane after the accident observed that the airplane sustained substantial damage to both wings during the runway excursion. The pilot reported the runway surface condition as “damp.” He further stated that it was not raining, there was no standing water on the runway and “If I had to choose between the descriptor of either wet or dry as my only options, I would choose dry.” According to automatic dependent surveillance broadcast (ADS-B) data, the airplane made a normal Vref approach and landed about 8 knots higher than the landing chart for 10,200 lbs about 110 knots. The runway length was 6,600 ft and about 4,500 ft of runway remained for the airplane to stop. The landing chart in the airplane flight manual (AFM) revealed that about 3,000 ft was required for landing on a dry runway, and about 3,750 ft was required for a wet runway. The anti-skid box, brake valve, anti-skid valve, and both wheel speed transducers were removed and sent to the manufacturer for testing. All the components passed the tests, and no anomalies were noted. The airplane was not equipped with a flight data recorder. The cockpit voice recorder was removed and sent the National Transportation Safety Board’s recorders laboratory for download. The airplane was not equipped with thrust reversers. The wind was reported from 150° at 5 knots, at APF, at 1235. The pilot stated that the flight was uneventful. During landing, he applied normal braking and the airplane started to slow down. Suddenly the brakes “faded away,” and he was unable to stop the airplane. He further described that he applied full braking pressure and the pedals were operating as they should, but the airplane was not stopping. He added that every few feet the brakes would grab, lock-up for a few feet, and then release. The brakes grabbed several times during the landing roll but were not slowing the airplane down. The airplane overran the end of the runway, and the pilot steered the airplane into the grass and away from a jet blast fence. The anti-skid box, brake valve, anti-skid valve, and both wheel speed transducers were removed and sent to the manufacturer for bench testing. All the components passed the bench tests, and no anomalies were noted. The airplane was not equipped with a flight data recorder. According to automatic dependent surveillance broadcast (ADS-B) data, the airplane landed about 8 knots higher than the Vref speed of 110 knots, with about 4,500 ft of runway remaining. According to the airplane flight manual, the airplane required about 3,000 ft for landing. Based on the available evidence, the reason that the pilot was unable to stop the airplane on the runway could not be determined. 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).
- — Not determined-Not determined-(general)-(general)-Unknown/Not determined
Verbatim from NTSB's published report. Source file
NTSB_2021_ERA21LA350.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 (runway excursion). Sourced from NASA NTRS, NTSB Safety Studies, FAA CAMI, AOPA Air Safety Institute, Embry-Riddle Scholarly Commons, arXiv, and the Semantic Scholar academic graph.
- SKYbrary (Eurocontrol) 2024 · SKYbrary article
Runway Excursion — SKYbrary Knowledge Base
SKYbrary runway excursion review — RE-OE (overruns) + RE-LO (lateral). Risk drivers: long landing, high approach speed, contaminated surface, tailwind, mis-set autobrakes.
- NTSB Aircraft Accident Reports 2019 · Accident report
Embraer ERJ 175 Runway Excursion at Charlotte Douglas
Republic Airline ERJ-175 runway excursion CLT, January 2018. Examines a low-energy runway excursion involving misuse of autobrakes + thrust reverser response after a high-crosswind landing on a contam…
- NASA NTRS 2025 · Presentation
Uncovering Resilient Behavior in the Aviation Safety Reporting System Using Large Language Models
Resiliency is present in everyday life, both in system design and exhibited by the operators that function within these systems.
- NASA NTRS 2025 · Conference Paper
Uncovering Resilient Behavior in the Aviation Safety Reporting System Using Large Language Models
Resiliency is present in everyday life, both in system design and exhibited by the operators that function within these systems.
- Flight Safety Foundation 2024 · FSF / AeroSafety World
Runway Safety Initiative Final Report (RSI)
Foundation Runway Safety Initiative final report — comprehensive analysis of runway excursion + incursion risk drivers worldwide.
- Semantic Scholar 2020 · Article
Towards online prediction of safety-critical landing metrics in aviation using supervised machine learning
Abstract In recent years, due to the increased availability of data and improvements in computing power, application of machine learning techniques to various aviation safety problems for identifying,…
Browse the full corpus — academia portal ↗