# NTSB CEN24LA088: Eurocopter AS 350 B2, N204TX, Spofford, TX, January 12, 2024 - Type: NTSB accident investigation - Classification: Accident · Minor injuries · Class 3 · Limited · Final report - Date: January 11, 2024, 19:00 local (Jan 12, 2024, 01:00 UTC) - Place: Spofford, TX - Coordinates: 29.1593, -100.4986 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=29.1593&lon=-100.4986&mi=10 - Phase of flight: [Enroute](https://openairdocs.org/ntsb-phases/400) (OpenAirDocs' grouping) - Defining event: [Enroute: Powerplant sys/comp malf/fail](https://openairdocs.org/ntsb-events/340) - Highest injury: Minor injuries - Injuries: 2 minor - Status: Completed - Report: Approved by Office Director - Investigation class: Class 3 - NTSB office: Central Region - Parties: Texas Department of Safety, Federal Aviation Administration, San Antonio FSDO, Safran Helicopter Engines, Airbus Helicopters North America, Bureau d'Enquêtes et d'Analyses pour la sécurité de l'aviation civile - NTSB case key (mKey): 193642 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=CEN24LA088 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/193642/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=193642 - Page: https://openairdocs.org/ntsb/CEN24LA088 ## Probable cause The fatigue failure of the fuel control unit control lever arm, which resulted in fuel starvation, and a loss of engine power. ## Findings NTSB's coded findings; those marked are part of the probable cause. - [Engine fuel and control: fuel controlling system](https://openairdocs.org/ntsb-findings/01057320): Aircraft › Aircraft power plant · Failure (probable cause); cases with it: [Eurocopter AS 350 B2, 1 case](https://openairdocs.org/ntsb-findings/01057320/cases.md?model=8680950), [All aircraft, 59 cases](https://openairdocs.org/ntsb-findings/01057320/cases.md) ## Sequence of events The events NTSB coded, in order, by phase of flight. The defining event best describes what happened. - [Enroute: Powerplant sys/comp malf/fail](https://openairdocs.org/ntsb-events/340) (defining event); cases with it: [Eurocopter AS 350 B2, 2 cases](https://openairdocs.org/ntsb-events/340/sequence.md?model=8680950), [All aircraft, 820 cases](https://openairdocs.org/ntsb-events/340/sequence.md) - [Enroute: Loss of engine power (total)](https://openairdocs.org/ntsb-events/341); cases with it: [Eurocopter AS 350 B2, 6 cases](https://openairdocs.org/ntsb-events/341/sequence.md?model=8680950), [All aircraft, 3,820 cases](https://openairdocs.org/ntsb-events/341/sequence.md) - [Autorotation: Collision with terr/obj (non-CFIT) ](https://openairdocs.org/ntsb-events/470); cases with it: [Eurocopter AS 350 B2, 16 cases](https://openairdocs.org/ntsb-events/470/sequence.md?model=8680950), [All aircraft, 10,189 cases](https://openairdocs.org/ntsb-events/470/sequence.md) ## Analysis The flight crew had competed their aerial observation and were enroute to the destination airport. While enroute, the pilot felt a violent yaw to the right, saw the engine low pressure annunciator illuminate, and heard the low rotor horn. After the engine lost power, the pilot transferred the flight controls to the copilot, who performed an autorotation and landed the helicopter in a brush-covered field. Postaccident examination and testing of the engine revealed that the engine’s fuel control unit (FCU) control lever arm was broken. Metallurgical examination of the control lever arm revealed it had failed due to a fatigue fracture which resulted in a loss of fuel control to the engine and fuel starvation. ## Factual narrative On January 11, 2024, at 1900 central standard time, a Eurocopter AS 350 B2, N204TX, was substantially damaged when it was involved in an accident near Spofford, Texas. The pilot and copilot received minor injuries. The helicopter was operated as a public aircraft conducting an aerial observation flight. During the flight, the pilot decided to return to his base when he saw that the fuel gauge indicated 20% fuel remaining. The engine instruments did not indicate any anomalies. The pilot then felt a violent yaw to the right, saw the engine low pressure annunciator illuminate, and heard the low rotor horn. The copilot asked the pilot what happened, and the pilot said that they had lost the engine. The pilot transferred controls to the copilot after the rotor rpm returned to the normal operating range. The copilot then performed an autorotation and landed the helicopter in a brush-covered field. The helicopter sustained substantial damage to the tail boom and main rotor. The engine was placed in a test cell for a postaccident engine run. During the run, the engine would not accelerate past 45% gas generator speed (Ng). The FCU, part number 0164851320, serial number 937B, was removed, and another FCU was installed. The engine then operated normally during the second test run. The FCU from the accident airplane was bench tested. The test revealed that it could not achieve maximum fuel flow per the test specifications. The FCU was then disassembled, and the FCU control lever arm, part number 0164042540, was found broken. National Transportation Safety Board Materials Laboratory examination of the broken FCU control lever arm revealed a crack with fine fatigue striations, typical of high-cycle or low-load fatigue. Outside of this crack, the fracture surface exhibited dimpled rupture, consistent with subsequent overstress fracture in the remaining lever arm. According to the examination report, these features were consistent with the initial fracture of the lever arm through about two-thirds of the cross-section. This crack or fracture edge of this early fracture then initiated fatigue cracking at multiple sites. Once the fatigue cracks had propagated deep enough, the remainder of the lever arm cross sections fractured via overstress. ## Aircraft - Registration: [N204TX](https://openairdocs.org/deregistered/N204TX-2025-12-29), registration cancelled 2025-12-29, S/N 3711, built 2003 (OpenAirDocs) - Reported make and model: EUROCOPTER AS 350 B2 - Registry model: [Eurocopter AS 350 B2](https://openairdocs.org/model/eurocopter-as-350-b2) (registry code 8680950) (OpenAirDocs) - Registry engine: [Turbomeca ARRIEL-1D1](https://openairdocs.org/engine/turbomeca-arriel-1d1) (registry code 60053, turbo-shaft) (OpenAirDocs) - Category: Helicopter - Serial number: 3711 - Year built: 2003 - Engines: Safran Aircraft Engines Arriel 1D1 712 horsepower turbo shaft - Damage: Substantial damage - Flight: Aerial observation, Public use - Operator: Texas Department of Public Safety - Registered owner: Texas Department of Public Safety - Airworthiness certificate: Standard, Normal - Last inspection: 100 hour, December 20, 2023, 9,547.3 hours before - Departed: DRT, Del Rio, TX - Destination: Same as departure - Equipment: ADS-B, Electronic multifunction display, Electronic primary flight display ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 39; injuries: minor; commercial; airplane ratings: single-engine land, multi-engine land; instrument ratings: airplane; medical: class 2, with waivers/limitations; last flight review August 25, 2023; seat: right; restraint: 4-point; flight hours: 768 total, 433 in this make and model, 584 as pilot in command, 61 in the last 90 days, 49 in the last 30 days, 0 in the last 24 hours - Co-pilot; age 54; injuries: minor; commercial; airplane ratings: single-engine land; instrument ratings: airplane; medical: class 2, with waivers/limitations; last flight review June 12, 2022; seat: left; restraint: 4-point; flight hours: 3,448 total, 3,430 in this make and model ## Weather - Conditions: Visual (VMC), Night/dark - Wind: 170° at 8 knots - Visibility: 10 statute miles - Lowest ceiling: none - Temperature: 70 °F, dew point 14 °F - Altimeter: 29.46 inHg - Observed at: 5T9, 26 nm away ## FAA reports on this event (1) The FAA's own accident and incident reports, matched to the aircraft by N-number and date (OpenAirDocs). - [Accident 20240111001379A](https://openairdocs.org/incident/20240111001379A), Jan 11, 2024: Eurocopter AS 350 B2, Brackettville, TX, Destroyed. On January 11, 2024, at approximately 1959 CST, an [privacy data omitted]helicopter utilized the emergency procedure “autorotation” and landed hard with… ## Docket (7 files) The files NTSB released with the investigation on February 13, 2025, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=193642. 7.8 MB in all. - Pilot/operator aircraft accident report, NTSB form 6120.1 (item 1, PDF, 11 pages, 2.2 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=17150131&FileExtension=pdf&FileName=6120%20Master_Redacted-Rel.pdf - Record of N204TX engine test and examination (item 2, PDF, 1 page, 67 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=17208938&FileExtension=pdf&FileName=MOR%20Engine%20Test%20Run-Rel.pdf - Fuel control unit maintenance records (item 3, PDF, 2 pages, 1.4 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=17150094&FileExtension=pdf&FileName=FCU%20Mx%20Records_Redacted-Rel.pdf - Materials laboratory factual report (item 4, PDF, 17 pages, 20 photos, 3.4 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=17575619&FileExtension=pdf&FileName=24-021%20-%20Materials%20Lab%20Factual%20Report%20(CEN24LA088)-Rel.pdf - Photos (item 5, PDF, 1 page, 418 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=17205563&FileExtension=pdf&FileName=Photo%20Template-Rel.pdf - Statement of party representatives to NTSB investigation (item 6, PDF, 1 page, 196 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=17190505&FileExtension=pdf&FileName=NTSB_Redacted-Rel.pdf - Memorandum for record - bea report review (item 7, PDF, 1 page, 64 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=18253794&FileExtension=pdf&FileName=MOR%20BEA%20Report%20Review-Rel.pdf From the NTSB's public API. Aircraft are matched to registry aircraft by N-number and event date, checked against the reported serial number, make and model; the registry's history has gaps, so older matches can be wrong. Compare the reported make and model. --- OpenAirDocs.org is an independent research project of [Contrail Labs](https://contraillabs.com/). It is not affiliated with the FAA or the NTSB. Source documents are U.S. government works in the public domain.