Accident Hiller UH-12E N4254X, Sunday 4 June 1995

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Date:	Sunday 4 June 1995
Time:	18:00 LT
Type:	Hiller UH-12E
Owner/operator:	Main Street Aviation, Inc
Registration:	N4254X
MSN:	1378
Total airframe hrs:	6183 hours
Engine model:	Lycoming VO-540-B1A
Fatalities:	Fatalities: 0 / Occupants: 1
Other fatalities:	0
Aircraft damage:	Substantial
Category:	Accident
Location:	Checotah, OK - United States of America
Phase:	Manoeuvring (airshow, firefighting, ag.ops.)
Nature:	Agricultural
Departure airport:
Destination airport:
Investigating agency:	NTSB
Confidence Rating:	Accident investigation report completed and information captured

Narrative:
WHILE DISPENSING A HERBICIDE, 'THE ENGINE LOST POWER, RPM, AND A VIBRATION WAS FELT. THE ENGINE RECOVERED TO FULL POWER CAUSING THE HELICOPTER TO YAW.' THIS EVENT OCCURRED THREE ADDITIONAL TIMES FOR UNDETERMINED REASONS DURING AN ATTEMPTED RUN-ON LANDING TO A FIELD. AS THE HELICOPTER'S SKIDS CONTACTED THE GROUND, THE PILOT HEARD A 'BOOM', THE HELICOPTER YAWED, THE SKIDS SEPARATED FROM THE FUSELAGE, AND THE HELICOPTER CAME TO REST ON ITS SIDE.

Probable Cause: THE PILOT ALLOWING THE HELICOPTER TO TOUCHDOWN IMPROPERLY. A FACTOR WAS THE ERRATIC RUNNING ENGINE.

Accident investigation: