# NTSB LAX99LA049: Bell 47G-3B-1, N3084G, Winterhaven, CA, December 4, 1998 - Type: NTSB accident investigation - Classification: Accident · No injuries · Limited investigation · Final report - Date: December 4, 1998, 01:00 local (09:00 UTC) - Place: Winterhaven, CA - Coordinates: 32.870479, -114.719604 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=32.8705&lon=-114.7196&mi=10 - Phase of flight: [Uncontrolled descent](https://openairdocs.org/ntsb-phases/650) (OpenAirDocs' grouping) - Highest injury: No injuries - Injuries: 1 uninjured - Status: Completed, report February 16, 2001 - Report: Approved by Office Director - NTSB case key (mKey): 45465 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=LAX99LA049 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/45465/pdf - Page: https://openairdocs.org/ntsb/LAX99LA049 ## Probable cause The failure of the pilot to maintain rotor rpm. A factor was his attempt to take off over gross weight. ## Sequence of events In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf). - In flight collision with terrain/water, descent - uncontrolled - rotor rpm - not maintained, pilot in command (cause) - aircraft weight and balance - inaccurate, pilot in command (contributing factor) - terrain condition - rough/uneven ## Analysis The pilot had been spraying the field for about 3 hours. He attempted to take off at or over gross weight and the rotor rpm began to decay. The helicopter was positioned perpendicular to the furrowed rows in the field and when the pilot attempted to land the left skid dug into the mud. The aircraft bounced forward and the main rotor blades flexed downward and severed the tailboom. The pilot reported that he had not experienced any mechanical discrepancies with the aircraft prior to the accident. He further stated that he had not experienced any problems with the engine during the accident. ## Factual narrative On December 4, 1998, at 0100 hours Pacific standard time, a Bell 47G-3B-1 helicopter, N3084G, lost rotor rpm on takeoff and impacted the ground near Winterhaven, California. The aircraft sustained substantial damage, and the commercial pilot, the sole occupant, was not injured. The aerial application flight was conducted under the provisions of 14 CFR Part 137, and the aircraft was being operated by Sundown Helicopters, Yuma, Arizona. The local flight originated about 2200. Night visual meteorological conditions prevailed and no flight plan was filed. The pilot reported that he had been spraying a field with fertilizer for 3 hours. He stopped for approximately 5 minutes to add "30 to 40 gallons of fuel and about 50 gallons of [spray] material." He reported that the takeoff seemed normal and the helicopter accelerated through translational lift. The pilot stated that the rotor rpm began to decay and he was unable to regain it. The aircraft was positioned perpendicular to the furrowed rows in the field, and when the pilot attempted to land, the left skid dug into the mud. The helicopter bounced forward and the main rotor blades flexed downward and cut through the tailboom. The pilot reported that he had not experienced any mechanical discrepancies with the aircraft prior to the accident. He further stated that he had not experienced any problems with the engine during the accident. According to the Bell Pilot Operator Handbook, the maximum gross weight for the Bell 47G-3B-1 is 2,950 pounds. The pilot supplied the weight and balance he had worked out for the accident flight, which listed a takeoff weight of 2,930.13 pounds. He calculated 35 gallons of 100 low lead aviation fuel at 6 pounds per gallon, totaling 210 pounds. Aviation fuel weighs 6.7 pounds; 35 gallons of fuel at 6.7 pounds per gallon equals 234.5 pounds. This calculation of fuel weight adds 24.5 gallons to the pilot's calculation of 2,930.13, bringing the takeoff weight to 2,954.63 pounds. ## Aircraft - Registration: [N3084G](https://openairdocs.org/deregistered/N3084G-2020-10-03), registration cancelled 2020-10-03, S/N 2916 (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) - Category: Helicopter - Serial number: 2916 - Airframe hours: 5521 - Engines: Lycoming TVO-435-BIA 270 horsepower reciprocating - Damage: Substantial damage - Flight: Aerial application, Part 137 - Registered owner: Sundown Helicopters - Airworthiness certificate: Standard, Normal - Last inspection: 100 hour, November 28, 1998, 8 hours before ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 51; commercial; airplane ratings: single-engine land; instrument ratings: helicopter, airplane; medical: class 2, valid medical--w/ waivers/lim; seat: left; flight hours: 18,065 total, 10,000 in this make and model, 17,533 as pilot in command, 215 in the last 90 days, 57 in the last 30 days, 6 in the last 24 hours ## Weather - Conditions: Visual (VMC), Night/dark - Wind: calm - Visibility: 5 statute miles - Lowest ceiling: none - Temperature: 52 °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 19981204039129A](https://openairdocs.org/incident/19981204039129A), Dec 4, 1998: Bell 47G3B1, Winterhaven, CA, Substantial damage. (-23) Agricultural operator had just received a 30-40 gallon fuel load and had taken on a 50 gallon load of pesticide. After taking off and leveling at… ## Other investigations on N3084G (3) 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 LAX01LA098](https://openairdocs.org/ntsb/LAX01LA098), Feb 10, 2001: Bell 47-G3B1 (N3084G), Winterhaven, CA, substantial damage. Probable cause: A failure of the transmission free wheeling unit due to improper maintenance. A factor was the dark night visual condition. - [NTSB LAX80FUA22](https://openairdocs.org/ntsb/LAX80FUA22), Sep 7, 1980: Bell 47G-3B (N3084G), Bellflower, CA, substantial damage - [NTSB LAX75DUG22](https://openairdocs.org/ntsb/LAX75DUG22), Nov 21, 1974: Bell 47G3B1 (N3084G), Joshua Tree, CA, 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.