NTSB CAROL · Event
Event MIA95LA078
Aircraft involved
Probable cause & findings
The pilot's misjudgment of altitude and failure to apply collective cushioning pitch during an autorotation resulting in a hard landing. Contributing to the accident was a total loss of engine power due to a loose coupling B-nut on the pneumatic fuel control system, and improper maintenance inspection of helicopter by unknown maintenance personnel.
Factual narrative
On February 20, 1995, about 1100 eastern standard time, a Hughes 500C, N7172Z, registered to Flying Gophers Inc., operating as a 14 CFR Part 91 personal flight, experienced a reported total loss of engine power in cruise flight in the vicinity of Key Largo, Florida. A forced landing was made on a public highway. Visual meteorological conditions prevailed and no flight plan was filed. The helicopter sustained substantial damage. The commercial pilot was not injured. The flight originated from Opa Locka Airport, Opa Locka, Florida, about 45 minutes before the accident. The pilot stated he was at 500 feet agl when he observed a high reading on the power turbine governor. He decreased the governor with the governor rpm switch and continued with the flight. About 1 minute later the helicopter experienced a total loss of engine power. The helicopter yawed to the left, followed by the illumination of the engine out warning light and engine out audio. He entered autorotation towards a highway. At 100 feet he initiated a deceleration and applied initial collective pitch at about 20 feet. Cushioning collective pitch was not applied. The helicopter collided with the ground ventral fin first, rocked forward, and slid about 150 feet before coming to a complete stop. An engine fuel and pneumatic system check was performed by McDonnell Douglas Field Service Representative under the supervision of the FAA on March 7, 1995. The fuel system failed the vacuum check. The hose assembly from the before filter (BF) port was loose at the fuel pressure switch after filter (AF) coupling B-nut of the engine-driven fuel pump. The engine was removed and transported to an authorized repair facility in Miami, Florida, for an engine test run. Before testing, it was noted that about 9cc of fuel was present in the engine-driven fuel pump filter bowl; an additional 1cc of fuel was present in the fuel nozzle inlet line. The coupling B-nut was tightened. The engine was run in a test cell on March 8, 1995, in the presence of the NTSB investigator-in-charge, and parties to the investigation. The engine started, ran, and developed adequate power. The AF filter side coupling B-nut of the fuel pressure differential switch was loosened 1 1/2 turns and the engine shut down. The pilot stated he was in cruise flight at 500 feet agl when he experienced a total loss of engine power. He entered autorotation towards a highway. At 100 feet he initiated a deceleration and applied initial collective pitch at about 20 feet. Collective cushioning pitch was not applied. The helicopter collided with the ground ventral fin first, rocked forward, and slid about 150 feet. Examination of the helicopter revealed the B-nut on the after filter coupling of the fuel pressure differential switch was loose. The coupling B-nut was tightened. The engine was run in an engine test cell and developed adequate power. When the coupling B-nut was loosened the engine shut down. Source: NTSB Aviation Accident Database (Pre-2008 Archive) Retrieved: 2026-02-12
Verbatim from NTSB's published report. Source file
NTSB_1995_MIA95LA078.txt.
Findings + structured fields enriched from FAA avall.mdb.
Full investigation docket on
data.ntsb.gov ↗.
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Related research
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Academic papers and agency reports matching this event's aircraft type or causal vocabulary (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 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…
- 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.
- Embry-Riddle Scholarly Commons 2024 · Journal article (IJAAA)
Just Culture in Aviation: A Metaphorical Study on Aircraft Maintenance Students
Just Culture, a sub-dimension of safety culture, has been a prominent and debated topic in aviation safety in recent years.
- Embry-Riddle Scholarly Commons 2024 · Journal article (IJAAA)
Performance PRISM: A Comprehensive Framework For Performance Measurement In Aircraft Maintenance
Aircraft maintenance is governed by rigorous safety requirements and high operational complexity, demanding robust performance measurement frameworks to ensure optimal maintenance practices.
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