# NTSB LAX95LA216: Bell 47-G5, N7923J, Coalinga, CA, June 18, 1995 - Type: NTSB accident investigation - Classification: Accident · No injuries · Limited investigation · Final report - Date: June 17, 1995, 22:30 local (Jun 18, 1995, 05:30 UTC) - Place: Coalinga, CA - Coordinates: 36.190948, -120.389419 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=36.1909&lon=-120.3894&mi=10 - Phase of flight: [Initial climb](https://openairdocs.org/ntsb-phases/350) (OpenAirDocs' grouping) - Highest injury: No injuries - Injuries: 1 uninjured - Status: Completed, report January 29, 1996 - Report: Approved by Office Director - NTSB case key (mKey): 29122 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=LAX95LA216 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/29122/pdf - Page: https://openairdocs.org/ntsb/LAX95LA216 ## Probable cause clutch slippage for undetermined reasons. A factor in the accident was the helicopter's low above ground altitude, which limited the pilot's time and ability to recover main rotor rpm. ## Sequence of events In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf). - Airframe/component/system failure/malfunction, takeoff - initial climb - rotor drive system,clutch assembly - slipped (cause) - reason for occurrence undetermined - rotor rpm - not corrected, pilot in command (cause) - altitude - inadequate (contributing factor) - In flight collision with terrain/water, descent - uncontrolled ## Analysis THE PILOT REPORTED THAT HE HAD JUST LIFTED OFF FROM A REFUELING TRUCK AND WAS RETURNING TO BASE AT LOW ALTITUDE FROM APPLYING CHEMICALS TO A FIELD WHEN HE NOTED A SPLIT IN THE ENGINE/ROTOR TACHOMETER. THE ENGINE RPM'S BEGAN TO INCREASE WHILE THE MAIN ROTOR SPEED BEGAN TO DECAY. HE WAS ATTEMPTING TO CORRECT THE PROBLEM WITH COLLECTIVE AND THROTTLE MANIPULATION WHEN THE HELICOPTER COLLIDED WITH THE GROUND. THE HELICOPTER WAS EXAMINED BY AN FAA AIRWORTHINESS INSPECTOR. HE REPORTED THAT NO ABNORMALITIES WERE NOTED WITH EITHER THE ENGINE, THE TRANSMISSION, OR THE FREEWHEELING UNIT. HEAT DISCOLORATION AND BURNED OIL RESIDUE WERE NOTED ON THE CLUTCH. ## Factual narrative On June 17, 1995, at 2230 hours Pacific daylight time, a Bell 47-G5 helicopter, N7923J, lost power to the main rotor and collided with crops while returning from an aerial application operation near Coalinga, California. The aircraft was operated by Breen Aviation, Inc., of Lemoore, California. Visual meteorological conditions prevailed at the time and no flight plan was filed. The helicopter was destroyed in the collision sequence. The certificated commercial pilot, the sole occupant, was not injured. The flight originated at a private strip near Huron, California, about 2200 hours as a local area agricultural application flight. The pilot reported that he had just lifted off from a refueling truck and was returning to base from applying chemicals to a field when he noted a split in the engine/rotor tachometer. The engine rpm's began to increase while the main rotor speed began to decay. He was attempting to correct the problem with collective and throttle manipulation when the helicopter collided with the ground. The helicopter was examined by a Federal Aviation Administration (FAA) airworthiness inspector from the Fresno, California, Flight Standards District Office. He reported that no abnormalities were noted with either the engine, the transmission, or the freewheeling unit. Heat discoloration and burned oil residue were noted on the clutch. ## Aircraft - Registration: [N7923J](https://openairdocs.org/deregistered/N7923J-2017-10-31), registration cancelled 2017-10-31, S/N 25040, built 1971 (OpenAirDocs) - Reported make and model: BELL 47-G5 - Registry model: [Bell 47G-5](https://openairdocs.org/model/bell-47g-5) (registry code 1181032) (OpenAirDocs) - Registry engine: [Lycoming VO-435 series](https://openairdocs.org/engine/lycoming-vo-435-series) (registry code 41525, reciprocating) (OpenAirDocs) - Category: Helicopter - Serial number: 25040 - Airframe hours: 7733 - Engines: LYCOMING VO-435-B1A 265 horsepower reciprocating - Damage: Destroyed - Flight: Positioning, Part 91 - Operator: Breen Aviation, Inc. - Registered owner: Gilbert Aviation - Airworthiness certificate: Special, Restricted (Special) - Last inspection: Annual, January 5, 1995, 17 hours before - Departed: 3CA4, HURON, CA ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 35; commercial; airplane ratings: single-engine land; instrument ratings: helicopter; medical: class 2, valid medical--no waivers/lim.; seat: center; flight hours: 5,800 total, 300 in this make and model ## Weather - Conditions: Visual (VMC), Night/dark - Wind: 330° at 12 knots - Visibility: 10 statute miles - Lowest ceiling: none - Temperature: 64 °F, dew point 45 °F - Altimeter: 30.00 inHg - Observed at: NLC, 15 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 19950617017369A](https://openairdocs.org/incident/19950617017369A), Jun 17, 1995: Bell 47G5, Coalinga, CA, Destroyed. Lost main rotor power returning to base. Needles split. Rotors slowed. Engine raced. Impacted. Clutch overheated. ## Other investigations on N7923J (4) 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. - [NTSB OAK78DVG52](https://openairdocs.org/ntsb/OAK78DVG52), Jun 21, 1978: Bell 47G5 (N7923J), Napa, CA, substantial damage - [NTSB OAK74DVD28](https://openairdocs.org/ntsb/OAK74DVD28), Mar 24, 1974: Bell 47G-5 (N7923J), Stockton, CA, substantial damage - [NTSB FTW73DRG47](https://openairdocs.org/ntsb/FTW73DRG47), Feb 2, 1973: Bell 47G-5 (N7923J), Harlingen, TX, substantial damage - [NTSB FTW73DRG30](https://openairdocs.org/ntsb/FTW73DRG30), Dec 7, 1972: Bell 47G-5 (N7923J), Harlingen, TX, substantial damage 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.