# NTSB CEN23LA025: Bell 206, N61KH, Greenville, IL, November 3, 2022 - Type: NTSB accident investigation - Classification: Accident · Minor injuries · Class 3 · Limited · Final report - Date: November 2, 2022, 19:48 local (Nov 3, 2022, 00:48 UTC) - Place: Greenville, IL - Coordinates: 38.834789, -89.374808 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=38.8348&lon=-89.3748&mi=10 - Phase of flight: [Initial climb](https://openairdocs.org/ntsb-phases/350) (OpenAirDocs' grouping) - Defining event: [Initial climb: Fuel starvation](https://openairdocs.org/ntsb-events/191) - Highest injury: Minor injuries - Injuries: 2 minor, 1 uninjured - Status: Completed - Report: Approved by Office Director - Investigation class: Class 3 - NTSB office: Central Region - Parties: Rolls-Royce, Honeywell, Transportation Safety Board of Canada, Kash Helicopter Services, Bell Textron, FAA Springfield FSDO - NTSB case key (mKey): 106242 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=CEN23LA025 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/106242/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=106242 - Page: https://openairdocs.org/ntsb/CEN23LA025 ## Probable cause The mechanic’s failure to inspect and clean the entire fuel nozzle assembly in accordance with the engine maintenance manual, which resulted in fuel starvation and a partial loss of engine power, an autorotation, and a hard landing. ## Findings NTSB's coded findings; those marked are part of the probable cause. - [Maintenance: scheduled/routine maintenance](https://openairdocs.org/ntsb-findings/02062010): Personnel issues › Task performance · Maintenance personnel (probable cause); cases with it: [Bell 206B, 4 cases](https://openairdocs.org/ntsb-findings/02062010/cases.md?model=1181511), [All aircraft, 320 cases](https://openairdocs.org/ntsb-findings/02062010/cases.md) - [Action: forgotten action/omission](https://openairdocs.org/ntsb-findings/02041035): Personnel issues › Action/decision · Maintenance personnel (probable cause); cases with it: [Bell 206B, 4 cases](https://openairdocs.org/ntsb-findings/02041035/cases.md?model=1181511), [All aircraft, 440 cases](https://openairdocs.org/ntsb-findings/02041035/cases.md) - [Attention/monitoring: task monitoring/vigilance](https://openairdocs.org/ntsb-findings/02021520): Personnel issues › Psychological · Maintenance personnel (probable cause); cases with it: [Bell 206B, 7 cases](https://openairdocs.org/ntsb-findings/02021520/cases.md?model=1181511), [All aircraft, 330 cases](https://openairdocs.org/ntsb-findings/02021520/cases.md) - [Fuel system: fuel distribution](https://openairdocs.org/ntsb-findings/01022820): Aircraft › Aircraft systems · Incorrect service/maintenance (probable cause); cases with it: [Bell 206B, 1 case](https://openairdocs.org/ntsb-findings/01022820/cases.md?model=1181511), [All aircraft, 141 cases](https://openairdocs.org/ntsb-findings/01022820/cases.md) ## Sequence of events The events NTSB coded, in order, by phase of flight. The defining event best describes what happened. - [Prior to flight: Aircraft maintenance event](https://openairdocs.org/ntsb-events/040); cases with it: [Bell 206B, 4 cases](https://openairdocs.org/ntsb-events/040/sequence.md?model=1181511), [All aircraft, 484 cases](https://openairdocs.org/ntsb-events/040/sequence.md) - [Initial climb: Fuel starvation](https://openairdocs.org/ntsb-events/191) (defining event); cases with it: [Bell 206B, 3 cases](https://openairdocs.org/ntsb-events/191/sequence.md?model=1181511), [All aircraft, 733 cases](https://openairdocs.org/ntsb-events/191/sequence.md) - [Initial climb: Attempted remediation/recovery](https://openairdocs.org/ntsb-events/060); cases with it: [Bell 206B, 14 cases](https://openairdocs.org/ntsb-events/060/sequence.md?model=1181511), [All aircraft, 1,422 cases](https://openairdocs.org/ntsb-events/060/sequence.md) - [Emergency descent: Attempted remediation/recovery](https://openairdocs.org/ntsb-events/060); cases with it: [Bell 206B, 14 cases](https://openairdocs.org/ntsb-events/060/sequence.md?model=1181511), [All aircraft, 1,422 cases](https://openairdocs.org/ntsb-events/060/sequence.md) - [Autorotation: Off-field or emergency landing](https://openairdocs.org/ntsb-events/440); cases with it: [Bell 206B, 21 cases](https://openairdocs.org/ntsb-events/440/sequence.md?model=1181511), [All aircraft, 3,365 cases](https://openairdocs.org/ntsb-events/440/sequence.md) - [Landing: Hard landing](https://openairdocs.org/ntsb-events/092); cases with it: [Bell 206B, 28 cases](https://openairdocs.org/ntsb-events/092/sequence.md?model=1181511), [All aircraft, 2,102 cases](https://openairdocs.org/ntsb-events/092/sequence.md) - [Post-impact: Evacuation](https://openairdocs.org/ntsb-events/460); cases with it: [Bell 206B, 1 case](https://openairdocs.org/ntsb-events/460/sequence.md?model=1181511), [All aircraft, 103 cases](https://openairdocs.org/ntsb-events/460/sequence.md) ## Analysis The pilot of the aerial application helicopter completed operations for the day and stopped to refuel on the way back to the operator’s facility. After refueling and during the initial climb, the pilot reported that he was unable to maintain main rotor rpm. The pilot initiated a 180° autorotation and landed hard on a grass area near a hangar. During the landing, the right-side skid collapsed, the tail boom separated, and the helicopter came to rest upright. The helicopter sustained substantial damage to the fuselage, the tail boom, and the tail rotor system. Examination of the engine revealed that the fuel nozzle inlet screen was contaminated and partially blocked with a buildup of debris. The fuel nozzle assembly had been inspected, as part of the required 150-hour inspection interval, 25.9 hours before the accident. The director of maintenance (DOM) for the operator was interviewed for additional details on how the inspection had been performed. The DOM reported that he had cleaned the fuel nozzle, but not the fuel nozzle inlet screen. When asked specifically about the fuel nozzle inlet screen cleaning, the DOM reported that he, “has not had a chance to get to that yet.” A review of the engine maintenance records showed that the DOM had signed his initials indicating that the fuel nozzle assembly was inspected and cleaned at the required 150-hour inspection interval. The partially blocked fuel nozzle inlet screen with debris likely restricted fuel flow to the engine. The DOM’s failure to clean the entire fuel nozzle assembly, including the fuel nozzle inlet screen, likely resulted in a partial loss of engine power, an autorotation, and a hard landing. Based on the available evidence, it is likely the DOM did not clean the fuel nozzle inlet screen for undetermined reasons. ## Factual narrative On November 2, 2022, about 1948 central daylight time, a Bell 206B helicopter, N61KH, sustained substantial damage when it was involved in an accident near Greenville, Illinois. The pilot and one passenger sustained minor injuries and one passenger sustained no injury. The helicopter was operated as a Title 14 Code of Federal Regulations (CFR) Part 91 business flight. The helicopter, which had a normal and a restricted airworthiness certificate, had completed 14 CFR Part 137 aerial application work during the day near Rushville, Illinois. The two passengers onboard were loaders employed by the operator. The helicopter was returning to the operator’s facility at the Mount Vernon Airport (MVN), Mount Vernon, Illinois, and stopped at the Greenville Airport (GRE), Greenville, Illinois, to refuel. After being refueled, the helicopter departed for MVN. During the initial climb, the pilot reported he was unable to maintain main rotor rpm. The pilot initiated a 180° autorotation to land back to the airport. The helicopter landed hard on a grass area near a hangar, the right-side skid collapsed, the tail boom separated, and the helicopter came to rest upright. The three occupants were able to egress from the helicopter without further incident. During the landing, the fuel system was damaged, and a large fuel leak occurred on the grass. The helicopter sustained substantial damage to the fuselage, the tail boom, and the tail rotor system. Postaccident examination of the airframe confirmed flight control continuity, and cockpit to engine control continuity was confirmed. Examination of the engine revealed that the fuel nozzle inlet screen was contaminated and partially blocked with a buildup of debris. The fuel nozzle assembly had been inspected, as part of the required 150-hour inspection interval, 25.9 hours before the accident. The DOM for the operator, who is an airframe and powerplant mechanic with inspection authorization, was interviewed for additional details on how the inspection had been performed. The DOM reported that he had cleaned the fuel nozzle, but not the fuel nozzle inlet screen. When asked specifically about the fuel nozzle inlet screen cleaning, the DOM reported that he, “has not had a chance to get to that yet.” The DOM further reported that he had never seen the fuel nozzle inlet screen before. A review of the engine maintenance records showed that the DOM had signed his initials indicating that the fuel nozzle assembly was inspected and cleaned at the required 150-hour inspection interval. Because of the smooth coated appearance of the debris on the fuel nozzle inlet screen as well as the highly variable color of fuel observed during the airframe examination, it was decided to perform testing on the fuel samples to determine if the fuel may have been contaminated with “apple jelly” or diesel exhaust fluid (DEF). The results of the testing found no “apple jelly” or DEF contamination with the helicopter’s fuel system. The Rolls-RoyceM250-C20 Series Operation and Maintenance Manual states that the fuel nozzle assembly is required to be removed, inspected, and cleaned at 150-hour intervals. The manual further states: NOTE: Operators can find it necessary to inspect and clean the fuel nozzle more often depending on past experience or operating conditions. The National Agricultural Aviation Association published the Fly Safe Message, Avoid Engine Fuel System Contamination, on May 1, 2023. This document discusses fuel system contamination with turbine-powered aircraft used for aerial application work and states in part: Contamination of an engine fuel system could result in either a partial or a complete loss of engine power. Turbine engine components that could be adversely affected by contamination include the fuel control unit and the fuel nozzles. Due to the nature of aerial application work, operators should consider increasing the inspection frequency of turbine engine fuel system components. Always follow the maintenance manual when performing your work. Consult with the airframe, the engine, and the engine accessory manufacturers on any additional service documents regarding the topic of fuel contamination. ## Aircraft - Registration: [N61KH](https://openairdocs.org/aircraft/N61KH), registered now, S/N 2255, built 1978 (OpenAirDocs) - Reported make and model: BELL 206 (B) - Registry model: [Bell 206B](https://openairdocs.org/model/bell-206b) (registry code 1181511) (OpenAirDocs) - Registry engine: [Allison 250 SER 250HP](https://openairdocs.org/engine/allison-250-ser-250hp) (registry code 03002, turbo-shaft) (OpenAirDocs) - Category: Helicopter - Serial number: 2255 - Year built: 1978 - Airframe hours: 15537.9 - Engines: Rolls-Royce 250-C20B 317 horsepower turbo shaft - Damage: Substantial damage - Flight: Business, Part 91 - Operator: Kash Helicopter Services LLC, doing business as Kash Helicopter Services LLC - Registered owner: Kash Helicopter Services LLC - Airworthiness certificate: Standard, Normal; Special, Restricted (Special) - Last inspection: AAIP, September 30, 2022, 25.9 hours before - Departed: Rushville, IL - Destination: Same as departure - Flight plan: Company VFR - Airport: GRE, Greenville, runway 36, 4,002 × 75 ft, grass/turf - Equipment: Handheld GPS, ADS-B ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 60; injuries: minor; commercial; airplane ratings: single-engine land; medical: class 2, without waivers/limitations; last flight review March 15, 2022; seat: right; restraint: 4-point; flight hours: 5,823 total, 1,800 in this make and model, 5,700 as pilot in command, 125 in the last 90 days, 25 in the last 30 days ## Weather - Conditions: Visual (VMC), Night - Wind: 140° at 6 knots - Visibility: 10 statute miles - Lowest ceiling: none - Temperature: 61 °F, dew point 46 °F - Altimeter: 30.17 inHg - Observed at: KBLV, 28 nm away - METAR: KBLV 030055Z 14006KT 10SM CLR 16/08 A3017 RMK AO2A PRESRR SLP220 T01560079 $ ## 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 20221102020039A](https://openairdocs.org/incident/20221102020039A), Nov 2, 2022: Bell 206B, Greenville, IL, Substantial damage. On November 2, 2022, at approximately 20:15 CST,[privacy data omitted]sustained substantial damage during an autorotation landing at the Greenville Airport… ## Docket (22 files) The files NTSB released with the investigation on September 5, 2024, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=106242. 46.5 MB in all. - Pilot/operator aircraft accident report, NTSB form 6120.1 (item 1, PDF, 9 pages, 1.5 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=16876698&FileExtension=pdf&FileName=NTSB%20Form%206120_1_Redacted-Rel.pdf - Accident photographs (item 2, PDF, 7 pages, 2.8 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=17030537&FileExtension=pdf&FileName=Accident%20Photographs-Rel.pdf - Various statements - occupants and witness (item 3, PDF, 5 pages, 953 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=16879062&FileExtension=pdf&FileName=Various%20Statements_Redacted-Rel.pdf - Statement - director of maintenance (item 4, PDF, 1 page, 67 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=16879481&FileExtension=pdf&FileName=CEN23LA025%20Daniel%20Cammack%20MOR-Rel.pdf - Additional questions - operator (item 5, PDF, 2 pages, 202 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=16880385&FileExtension=pdf&FileName=CEN23LA025%20(N61KH,%20Bell%20206B)%20-%20Additional%20Maintenance%20Questions_Redacted-Rel.pdf - N61KH - accident flight ADS-B data, google earth file (.kmz) (item 6, KMZ, 295 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=16876297&FileExtension=kmz&FileName=20221102_A7ED4E_499747293-Rel.kmz - N61KH - accident flight ADS-B data, microsoft excel file (.xlsx) (item 7, XLSX, 11.8 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=16876631&FileExtension=xlsx&FileName=20221102_A7ED4E_499747293_ADSB-Rel.xlsx - N61KH - most recent airframe maintenance records (item 8, PDF, 7 pages, 3.0 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=16971808&FileExtension=pdf&FileName=N61KH%20Most%20Recent%20Airframe%20Maintenance%20Records_Redacted-Rel.pdf - N61KH - most recent engine maintenance records (item 9, PDF, 8 pages, 7.4 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=16972760&FileExtension=pdf&FileName=N61KH%20Most%20Recent%20Engine%20Maintenance%20Records_Redacted-Rel.pdf - Wreckage examination factual report (item 10, PDF, 11 pages, 7 photos, 689 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=15428280&FileExtension=pdf&FileName=CEN23LA025%20Wreckage%20Examination%20Factual%20(FINAL)-Rel.pdf - Powerplants factual report (item 11, PDF, 26 pages, 2.7 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=16808263&FileExtension=pdf&FileName=CEN23LA025-pp-fact-z0-Rel.pdf - Attachment I - KTS fuel nozzle test (item 12, PDF, 4 pages, 1.5 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=16808517&FileExtension=pdf&FileName=Att1-KTS%20fuel%20nozzle%20test_Redacted-Rel.pdf - Attachment ii - rolls royce M250-C20 omm nozzle (item 13, PDF, 7 pages, 272 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=16808191&FileExtension=pdf&FileName=Att2-M250-C20%20OMM%20nozzle-Rel.pdf - Attachment iii - SAIB AIR-21-08 (item 14, PDF, 8 pages, 497 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=16808866&FileExtension=pdf&FileName=Att3-SAIB%20AIR-21-08-Rel.pdf - Attachment iv - ptg test report (item 15, PDF, 3 pages, 1.8 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=16808281&FileExtension=pdf&FileName=Att4-PTG%20PN%202524769%20SN%20BR33054_Redacted-Rel.pdf - Attachment v - fcu test report (item 16, PDF, 6 pages, 4.3 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=16809011&FileExtension=pdf&FileName=Att5-FCU%20PN%202524644%20SNBR52262_Redacted-Rel.pdf - Attachment VI - fuel test report (item 17, PDF, 39 pages, 1.6 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=16808759&FileExtension=pdf&FileName=Att6-RR%20DEF%20and%20Apple%20Jelly%20Report-Rel.pdf - Fuel information (item 18, PDF, 2 pages, 399 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=16879609&FileExtension=pdf&FileName=Fuel%20Information_Redacted-Rel.pdf - Weight and balance information (item 19, PDF, 8 pages, 2.0 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=16879072&FileExtension=pdf&FileName=Weight%20and%20Balance%20Information_Redacted-Rel.pdf - National agricultural aviation association, fly safe message - avoid engine fuel system contamination (item 20, PDF, 1 page, 159 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=16875636&FileExtension=pdf&FileName=FlySafe05013-Rel.pdf - Release of aircraft wreckage, NTSB form 6120.15 (item 21, PDF, 3 pages, 257 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=16880016&FileExtension=pdf&FileName=N61KH%20Wreckage%20Release%20Information_Redacted-Rel.pdf - NTSB party member forms - various (item 22, PDF, 5 pages, 2.3 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=16886831&FileExtension=pdf&FileName=NTSB%20Party%20Member%20Forms_Redacted-Rel.pdf From the NTSB's public API. 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