# NTSB LAX94LA200: Bell 47G-3B-1, N304JP, Yuma, AZ, April 17, 1994 - Type: NTSB accident investigation - Classification: Accident · No injuries · Limited investigation · Final report - Date: April 16, 1994, 20:00 local (Apr 17, 1994, 03:00 UTC) - Place: Yuma, AZ - Coordinates: 32.720794, -114.509002 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=32.7208&lon=-114.5090&mi=10 - Phase of flight: [Maneuvering](https://openairdocs.org/ntsb-phases/450) (OpenAirDocs' grouping) - Highest injury: No injuries - Injuries: 1 uninjured - Status: Completed, report November 14, 1994 - Report: Approved by Office Director - NTSB case key (mKey): 28727 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=LAX94LA200 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/28727/pdf - Page: https://openairdocs.org/ntsb/LAX94LA200 ## Probable cause an uncommanded engine deceleration to idle due to the improper installation of the throttle arm on the carburetor shaft. ## Sequence of events In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf). - Loss of engine power(total) - mech failure/malf, maneuvering - aerial application - throttle/power lever,bellcrank - separation (cause) - maintenance,installation - improper, other maintenance personnel (cause) - Forced landing, descent - emergency - Hard landing, landing - flare/touchdown ## Analysis The pilot reported that the helicopter had completed a swath run and was pulling up to clear a line of trees when the engine decelerated to idle. The pilot entered an autorotation and landed hard, damaging the skids and the fuselage. Postaccident inspection of the engine revealed that the throttle arm had come off the carburetor throttle body shaft. The operator stated that the arm and shaft were new components, installed on February 24, 1994, by a contract mechanic. The operator also stated that an 'excessive amount (about 2 inches) of safety wire was on the arm, which allowed the arm to slip off the shaft.' ## Factual narrative On April 16, 1994, at 2000 mountain standard time, a Bell 47G-3B- 1 helicopter, N304JP, landed hard following a loss of engine power while engaged in aerial application operations near Yuma, Arizona. The helicopter was owned and operated by Sundown Helicopters, Inc., of Yuma, Arizona, under the provisions of 14 CFR Part 137 of the Federal Aviation Regulations. Visual meteorological conditions prevailed at the time and no flight plan was filed for the operation. The aircraft incurred substantial damage. The certificated commercial pilot, the sole occupant, was not injured. The flight originated from the field to be sprayed about 1915 hours on the day of the accident. The operator and pilot reported that the helicopter had completed a swath run and was pulling up to clear a line of trees when the engine decelerated to idle. The pilot entered an autorotation and landed hard, damaging the skids and the fuselage. Postaccident inspection of the engine revealed that the throttle arm had come off the carburetor throttle body shaft. The operator stated that the arm and shaft were new components, installed on February 24, 1994, by a contract mechanic. The operator also stated that an "excessive amount (about 2 inches) of safety wire was on the arm, which allowed the arm to slip off the shaft." ## Aircraft - Registration: [N304JP](https://openairdocs.org/deregistered/N304JP-2025-01-04), registration cancelled 2025-01-04, S/N 3598, built 1966 (OpenAirDocs) - Reported make and model: BELL 47G-3B-1 - Registry model: [Bell 47G-3B-1](https://openairdocs.org/model/bell-47g-3b-1) (registry code 1181028) (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: 3598 - Airframe hours: 15222 - Engines: LYCOMING V0-435-AIF 260 horsepower reciprocating - Damage: Substantial damage - Flight: Aerial application, Part 137 - Operator: Sundown Helicopters, Inc. - Registered owner: Sundown Helicopters, Inc. - Airworthiness certificate: Special, Restricted (Special) - Last inspection: 100 hour, April 4, 1994, 23 hours before ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 47; flight instructor, commercial; airplane ratings: single-engine land; instrument ratings: airplane, helicopter; medical: class 2, valid medical--w/ waivers/lim; seat: left; flight hours: 15,163 total, 6,500 in this make and model, 14,637 as pilot in command, 167 in the last 90 days, 46 in the last 30 days, 3 in the last 24 hours ## Weather - Conditions: Visual (VMC), Dusk - Wind: 320° at 2 knots - Visibility: 40 statute miles - Lowest ceiling: none - Temperature: 72 °F ## 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 19940416009079A](https://openairdocs.org/incident/19940416009079A), Apr 16, 1994: Bell 47G3B1, Yuma, AZ, Substantial damage. On pullup from spray run engine went to idle. Brief autorotation and impact. Throttle disconnected. Recent repair. 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.