NTSB CAROL · Event
Event LAX99LA237
Registry · N7173F
FAA Aircraft Registry record.
Make / Model
HILLER UH-12E
TCDS
4H11 · SIAM HILLER HOLDINGS INC
Engine
ALLISON 250-C20 SER (420 hp)
Seats / Engines
4 seats · 1 engine
Last airworthiness date
19910805
ADS-B equipped
Yes — Mode-S A998D5
Registrant of record
FOUR CREEKS AVIATION INC
Source: FAA Aircraft Registry (releasable master file).
Aircraft involved
Probable cause & findings
The pilot's inadequate preflight planning and verification that fuel was available for the intended flight. A factor was the fuel quantity false indication.
Factual narrative
On June 30, 1999, about 0700 hours Pacific daylight time, a Hiller UH-12ET, N7173F, was substantially damaged during a forced landing in a rice field at Williams, California. The commercial pilot was not injured. The helicopter was being operated by Pacific Valley Aviation of Colusa, California, under the provisions of 14 CFR Part 137. A company visual flight plan was filed. Visual meteorological conditions prevailed for the local area agricultural flight, which originated near the field to be sprayed about 0630. The pilot stated that the engine abruptly quit while spraying the rice field and the forced landing resulted in the severing of the tail boom. He reported the turbine powered helicopter had been fueled the day before the accident, however, he did not visually confirm it. He had only flown 0.5 hours during this flight. Subsequent examination of the fuel system revealed a broken wire at the aft liquidometer. According to the UH-12E maintenance manual, an open circuit between pin A of the fuel gauge and pin C of the aft tank liquidometer would cause the gauge to indicate 34 gallons when the tank is empty. The pilot/operator failed to file a Safety Board Pilot Operator Accident Report, form 6120.1/2. While spraying a rice field the engine suddenly quit. The pilot force landed in the field severing the tail boom. The pilot reported the turbine powered helicopter had been fueled the day before the accident, however, he did not visually confirm it. The aircraft had only flown 0.5 hours during this flight. Examination of the fuel system revealed a broken wire in the fuel quantity indicating system. According to the maintenance manual for this helicopter, the open circuit caused by the wire breakage will cause a fuel quantity indication of 34 gallons when the tank is empty. Source: NTSB Aviation Accident Database (Pre-2008 Archive) Retrieved: 2026-02-12
Verbatim from NTSB's published report. Source file
NTSB_1999_LAX99LA237.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 (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.
Browse the full corpus — academia portal ↗