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Accidents · NTSB LAX91LA388 · Final report

Texas Helicopter M74 accident near Farmington, California, September 11, 1991

On September 11, 1991 at about 2:58 pm local time, a Texas Helicopter M74, registered N43921, was destroyed in an accident near Farmington, California. It was an aerial application (crop spraying) flight under agricultural flying rules (Part 137). 1 person was killed. The weather was visual conditions (good weather).

The NTSB's probable cause their words, unchanged

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).

Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.

What the record shows

Date
September 11, 1991 · about 2:58 pm local time
Place
Farmington, California · map
Type
Accident
Injuries
1 person was killed.
Weather
visual conditions (good weather)
Aircraft
Texas Helicopter M74
Registration
N43921 · registry record · serial 76-003
Damage
Destroyed
Flight
Aerial application (crop spraying) flight · agricultural flying rules (Part 137)

The NTSB's narrative final · quoted from the NTSB record

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.

The complete narrative as the NTSB published it. The NTSB's docket holds the report as a PDF and any photographs, statements and other documents from the investigation.

The factual record from the NTSB's investigation tables, in plain English

Pilot

  • Certificate: commercial pilot
  • Ratings: single-engine land; rotorcraft: helicopter
  • Flight time: 7,000 hours in all
  • Medical certificate: Class 2 (invalid medical for flight)
  • Seat: ctr

The aircraft

  • Last inspection: inspection type not recorded, January 2, 2000
  • Maximum gross weight: 2,450 lb
  • Seats: 1
  • Landing gear: fixed
  • Engine: Lycoming VO-435 (piston); 0 hours total
  • Fire on the ground
  • Operator: Ag-Air, INC

The flight

  • Flight plan: none
  • Runway 0

Weather at the time

  • Light: daylight
  • Wind: from 310° at 7 knots
  • Visibility: 10 statute miles
  • Sky: clear
  • Temperature: 61°F (16°C), dew point 0°F (-18°C)

Injuries

FatalSeriousMinorNone
Crew1

Documents from the investigation the NTSB's docket: the evidence folder behind the report

The docket, the folder of records gathered during an investigation (maintenance records, photographs, witness statements, examinations), has not been read from the NTSB for this case yet; the list appears here once it has. Open the docket at the NTSB.

Other NTSB records under N43921 the same tail number, which may have belonged to a different aircraft at the time

2012-02-22WPR12LA115 · accident near Farmington, CA · substantial damage · serious injuries
1990-08-27LAX90DVD03 · accident near Stockton, CA · substantial damage · no injuries

Everything on this page comes from the NTSB's public records. The narrative, probable cause and findings are the NTSB's own words; the coded tables behind the report are written out in plain English, with pilots' ages, home towns and medical details left out. The documents and photographs are the NTSB's docket, shown as the NTSB released them. This site's own text never names anyone involved. A preliminary report can change; the final report usually follows one to two years later, and the page is refreshed when it does.