NTSB Identification: LAX91LA388.
The docket is stored on NTSB microfiche number 45501.
Accident occurred Wednesday, September 11, 1991 in FARMINGTON, CA
Probable Cause Approval Date: 09/29/1993
Aircraft: TEXAS HELICOPTER M74, registration: N43921
Injuries: 1 Fatal.

NTSB investigators may not have traveled in support of this investigation and used data provided by various sources to prepare this aircraft accident report.

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 National Transportation Safety Board determines the probable cause(s) of this accident to be:

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).

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