# NTSB LAX91LA388: Texas Helicopter M74, N43921, Farmington, CA, September 11, 1991 - Type: NTSB accident investigation - Classification: Accident · Fatal · Limited investigation · Final report - Date: September 11, 1991, 07:58 local (14:58 UTC) - Place: Farmington, CA - Coordinates: 37.960289, -120.869049 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=37.9603&lon=-120.8690&mi=10 - Phase of flight: [Initial climb](https://openairdocs.org/ntsb-phases/350) (OpenAirDocs' grouping) - Highest injury: Fatal - Injuries: 1 fatal - Status: Completed, report September 29, 1993 - Report: Approved by Office Director - NTSB case key (mKey): 27354 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=LAX91LA388 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/27354/pdf - Page: https://openairdocs.org/ntsb/LAX91LA388 ## Probable cause LOSS OF ENGINE POWER FOR AN UNDETERMINED REASON. FACTORS RELATED TO THE ACCIDENT WERE: THE EXCESSIVE GROSS WEIGHT OF THE HELICOPTER, AND THE PILOT'S IMPROPER USE OF FLIGHT CONTROLS DUE TO IMPAIRMENT FROM USE OF A DRUG (MARIJUANNA). ## Sequence of events In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf). - Loss of engine power, takeoff - initial climb - reason for occurrence undetermined (cause) - Forced landing, descent - emergency - autorotation - performed, pilot in command - In flight collision with terrain/water, landing - aircraft weight and balance - exceeded, pilot in command (contributing factor) - flight controls - improper use of, pilot in command (contributing factor) - impairment(drugs), pilot in command (contributing factor) - Propeller/rotor contact to person, other ## Analysis AFTER THE HELICOPTER WAS RELOADED WITH 500 LBS OF SULFUR, THE PILOT TOOK OFF & DEPARTED TO THE NORTHWEST AT AN ALTITUDE OF ABOUT 100 FT TO CONTINUE THE APPLICATION MISSION. THE GROUND CREW REPORTED THAT SHORTLY AFTER DEPARTURE, THE ENGINE BACKFIRED SEVERAL TIMES & THE HELICOPTER BEGAN SETTLING TAIL FIRST TO THE GROUND. GROUND CONTACT SEPARATED THE TAIL BOOM FROM THE HELICOPTER & IT ROTATED TO THE LEFT. THE SKIDS SEPARATED & THE RIGHT SULFUR TANK RUPTURED. A SULFUR FIRE ERUPTED. THE PILOT EXITED THE COCKPIT ON THE RIGHT SIDE & WAS STRUCK BY THE MAIN ROTOR. THE HELICOPTER WAS LOADED 69 LBS OVER ITS MAXIMUM ALLOWABLE GROSS WEIGHT. NO PREIMPACT PART FAILURE OF THE HELICOPTER OR ENGINE WAS FOUND. TESTS OF THE PILOT'S BLOOD SHOWED 0.009 UG/ML OF 11-NOR-DELTA-9-TETRAHYRDROCANNABINOL & 0.012 UG/ML OF 11-NOR-DELTA-9-THC-9-CARBOXYLIC ACID. A TEST OF HIS URINE DETECTED 0.129 UG/ML OF 11-NOR-DELTA-9-CARBOXYLIC ACID. ## Aircraft - Registration: [N43921](https://openairdocs.org/aircraft/N43921), registered now, S/N 76-003, built 1977 (OpenAirDocs) - Reported make and model: TEXAS HELICOPTER M74 - Registry model: [Texas Helicopter OH-13E/M74](https://openairdocs.org/model/texas-helicopter-oh-13e-m74) (registry code 8930103) (OpenAirDocs) - Registry engine: [Lycoming VO-540 series](https://openairdocs.org/engine/lycoming-vo-540-series) (registry code 41534, reciprocating) (OpenAirDocs) - Category: Helicopter - Serial number: 76-003 - Engines: LYCOMING VO-435 240 horsepower reciprocating - Damage: Destroyed - Fire: On-Ground - Flight: Aerial application, Part 137 - Operator: Ag-Air, Inc - Registered owner: Ag Air, Inc - Airworthiness certificate: Special, Restricted (Special) - Last inspection: Unknown, January 2, 2000 ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 39; commercial; airplane ratings: single-engine land; medical: class 2, invalid medical for flight; seat: center; toxicology performed; flight hours: 7,000 total ## Weather - Conditions: Visual (VMC), Day - Wind: 310° at 7 knots - Visibility: 10 statute miles - Lowest ceiling: none - Temperature: 61 °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 19910911039289A](https://openairdocs.org/incident/19910911039289A), Sep 11, 1991: Bell OH13ETEXHELI, Farmington, CA, Destroyed, 1 fatal. Engine backfired on takeoff. Settled tail first to ground. Pilot hit by main rotor. Helicopter over gross weight. ## Other investigations on N43921 (2) 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 WPR12LA115](https://openairdocs.org/ntsb/WPR12LA115), Feb 22, 2012: Texas Helicopter OH-13E/M74 (N43921), Farmington, CA, substantial damage. Probable cause: The in-flight separation of the wood portion of one main rotor blade while maneuvering at low level, the reason for which could not be determined because postaccident examination did not reveal any… - [NTSB LAX90DVD03](https://openairdocs.org/ntsb/LAX90DVD03), Aug 27, 1990: Texas Helicopter M47A Wasp (N43921), Stockton, CA, substantial damage. Probable cause: THE PILOT MISJUDGED THE ALTITUDE DURING THE FLARE/TOUCHDOWN PHASE OF THE AUTOROTATION. FACTORS RELATING TO THIS ACCIDENT ARE FAILURE OF THE RIGHT MAGNETO. 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.