# NTSB CHI08CA210: Bell 47G-3B-2, N4029G, Lafetyette, IN, July 24, 2008 - Type: NTSB accident investigation - Classification: Accident · No injuries · Data collection · Final report - Date: July 24, 2008, 12:00 local (16:00 UTC) - Place: Lafetyette, IN - Coordinates: 40.459445, -86.753608 - Nearby events: https://openairdocs.org/map.md?lat=40.4594&lon=-86.7536&mi=10 - Phase of flight: [Maneuvering](https://openairdocs.org/ntsb-phases/450) (OpenAirDocs' grouping) - Defining event: [Maneuvering-low-alt flying: Loss of engine power (total)](https://openairdocs.org/ntsb-events/341) - Highest injury: No injuries - Injuries: 1 uninjured - Status: Completed, report September 26, 2008 - Report: Approved by Office Director - NTSB case key (mKey): 68794 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=CHI08CA210 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/68794/pdf - Page: https://openairdocs.org/ntsb/CHI08CA210 ## Probable cause The loss of engine power during an aerial application flight due to a fatigue fracture of the carburetor heat control valve spring and the inadequate maintenance inspection by the pilot/mechanic. An additional cause was the low altitude of the operation. ## Findings NTSB's coded findings; those marked are part of the probable cause. - [Engine fuel and control: fuel control/carburetor](https://openairdocs.org/ntsb-findings/01057322): Aircraft › Aircraft power plant · Fatigue/wear/corrosion (probable cause); cases with it: [Bell 47G-3B-2, 1 case](https://openairdocs.org/ntsb-findings/01057322/cases.md?model=1181029), [All aircraft, 195 cases](https://openairdocs.org/ntsb-findings/01057322/cases.md) - [Inspection: scheduled/routine inspection](https://openairdocs.org/ntsb-findings/02061520): Personnel issues › Task performance · Pilot (probable cause); cases with it: [Bell 47G-3B-2, 1 case](https://openairdocs.org/ntsb-findings/02061520/cases.md?model=1181029), [All aircraft, 167 cases](https://openairdocs.org/ntsb-findings/02061520/cases.md) ## Sequence of events The events NTSB coded, in order, by phase of flight. The defining event best describes what happened. - [Maneuvering-low-alt flying: Loss of engine power (total)](https://openairdocs.org/ntsb-events/341) (defining event); cases with it: [Bell 47G-3B-2, 1 case](https://openairdocs.org/ntsb-events/341/sequence.md?model=1181029), [All aircraft, 3,820 cases](https://openairdocs.org/ntsb-events/341/sequence.md) - [Emergency descent: Off-field or emergency landing](https://openairdocs.org/ntsb-events/440); cases with it: [Bell 47G-3B-2, 2 cases](https://openairdocs.org/ntsb-events/440/sequence.md?model=1181029), [All aircraft, 3,365 cases](https://openairdocs.org/ntsb-events/440/sequence.md) - [Landing: Collision with terr/obj (non-CFIT) ](https://openairdocs.org/ntsb-events/470); cases with it: [Bell 47G-3B-2, 1 case](https://openairdocs.org/ntsb-events/470/sequence.md?model=1181029), [All aircraft, 10,189 cases](https://openairdocs.org/ntsb-events/470/sequence.md) ## Analysis The helicopter began losing engine power during an aerial application run while maneuvering. The pilot attempted a landing in the field and the helicopter impacted terrain about 80 yards from an access road at the north edge of the field. The helicopter sustained substantial damage. The pilot was uninjured. Examination of the helicopter revealed that the carburetor heat control spring that keeps the carburetor closed was broken and its support rod had worn into the housing. The heat valve could only be opened about 1/3 and while corresponding cockpit control remained in the closed position. The fracture surface of the spring was consistent with fatigue. The spring had accumulated a total time in service of 832 hours. The pilot was a certificated aircraft mechanic who also performed maintenance on the helicopter. A National Transportation Safety Board Pilot/Operator Aircraft Accident/Incident Report was not received from the pilot. ## Factual narrative The helicopter began losing engine power during an aerial application while maneuvering. The pilot attempted a landing in the field where the helicopter impacted terrain about 80 yards from an access road at the north edge of the field. The helicopter sustained substantial damage. The pilot was uninjured. Examination of the helicopter revealed that the carburetor heat control spring that keeps the carburetor closed was broken and its support rod had worn into the housing. The heat valve could only be opened about 1/3 and while corresponding cockpit control remained in the closed position. The fracture surface of the spring was consistent with fatigue. The spring accumulated a total time in service of 832 hours. The pilot was a certificated aircraft mechanic who also performed maintenance on the helicopter. A National Transportation Safety Board Pilot/Operator Aircraft Accident/Incident Report was not received from the pilot. ## Aircraft - Registration: [N4029G](https://openairdocs.org/aircraft/N4029G), registered now, S/N 6700, built 1968 (OpenAirDocs) - Reported make and model: Bell 47G-3B-2 - Registry model: [Bell 47G-3B-2](https://openairdocs.org/model/bell-47g-3b-2) (registry code 1181029) (OpenAirDocs) - Registry engine: [Lycoming TVO-435-GIA](https://openairdocs.org/engine/lycoming-tvo-435-gia) (registry code 41526, turbo-prop) (OpenAirDocs) - Category: Helicopter - Serial number: 6700 - Engines: Lycoming TVO-435 reciprocating - Damage: Substantial damage - Flight: Aerial application, Part 137 - Operator: Townsend Aviation Inc. - Registered owner: Wildhorse Helicopters Inc. - Airworthiness certificate: Special, Restricted (Special) - Departed: Lafetyette, IN - Destination: Laffetyette, IN ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 32; commercial; airplane ratings: single-engine land, multi-engine land; instrument ratings: helicopter, airplane; medical: class 2; flight hours: 1,200 total, 100 in this make and model ## Weather - Conditions: Visual (VMC), Day ## 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 20080724843519A](https://openairdocs.org/incident/20080724843519A), Jul 24, 2008: Bell 47G3B2, Lafayette, IN, Substantial damage. (-23) On July 24,2008, at approximately 1200 EDT, while operating his Bell 47G3B2, N4029G, [privacy data omitted] executed an emergency landing in a cornfield… 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.