FLIGHT FINDINGSAVIATION OCCURRENCE MAP
Back to map

LAX91LA388 · Texas Helicopter M74

11 Sept 1991 · FARMINGTON, CA, United States

Ag Air Texas Helicopter M74 · Accident: loss of engine power during initial climb

Report a problem

Event

NTSB case
LAX91LA388
Event typeAccident: someone killed or seriously injured, or the aircraft substantially damaged (NTSB definition). Incident: an occurrence that affected or could have affected safety, short of that. Glossary
Accident
InvestigationHow far the investigation had got when the record was published: preliminary, ongoing, final or completed. Unknown where the source does not say. Glossary
Completed
API-reported fatalities
1 · all aircraft and ground
Ground fatalities
0
OperationWhat kind of flying it was, grouped by the rules it flew under: airline (US Part 121), air taxi and commuter (Part 135), general aviation (Part 91 and similar), military or government. Glossary
General aviation
WeatherVisual meteorological conditions (VMC): good enough to fly by looking outside. Instrument conditions (IMC): cloud or low visibility, flying by instruments. Glossary
Visual Meteorological Cond

Texas Helicopter M74

Aircraft type
Texas M74
Category
Helicopter
RegistrationThe aircraft's tail number, such as N12345 or G-ABCD. Registrations are reissued, so the same one years apart can be a different aircraft. Glossary
N43921
Operator
Ag-Air
Onboard fatalities
Unknown
Route
From not recordedTo not recorded
Aircraft age
Not recorded
Flight rulesThe regulations the flight operated under: in the US, Part 91 (general aviation), Part 121 (airlines), Part 135 (air taxi and commuter) and others; for flights abroad, the NTSB's coarser commercial or non-commercial code. Glossary
Part 137: Agricultural
Phase of flightThe stage of the flight when things started to go wrong: standing, taxi, takeoff, initial climb, en route, maneuvering, approach or landing. Glossary
Initial climb
First occurrenceThe single coded event the NTSB judges best describes what happened (records from 2008 on). Older records name the first occurrence in the sequence instead. Glossary
Loss of engine power
DamageDestroyed: beyond practical repair. Substantial: damage that affects the structure, performance or handling and normally needs major repair. Minor: less than that. Glossary
Destroyed

Cause areas

  • Reason for occurrence undetermined

Approximate · Coordinates as recorded by the NTSB; no uncertainty radius is established.

NTSB narrative

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.

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).

Verbatim NTSB analysis and probable cause from the NTSB dataset

Sources

NTSB record LAX91LA388
Event ID
20001212X18118
Case number
LAX91LA388
Dataset
historical-pre2008
Source SHA-256
89e2df6d848e7ab3b42e7d7c7a03ff403303057a26ca04c95b3ea67201c3ce74
Source notes (4)
  • Unreviewed is an editorial label, not an investigation status. API-sourced is not report-checked or human-reviewed. Explicit event totals are used without summing aircraft injury tables; onboard allocation is withheld. Unknown values remain unknown. The operation category is mapped from the NTSB-reported FAR part and has not been reviewed.
  • Filled from the NTSB case API where the bulk record had no value: investigation status. Values present in the bulk record are kept.
  • The date is the local date, which is the same as the UTC date the NTSB stores.
  • API snapshot SHA-256: 4ff1e166d01bc0191b28bece782a0fe6c8d3aab777b60e2e62d704f673aa634d; retrieved 2026-09-21T01:35:26.251Z.