Accident PZL-M-18 Dromader N4506K, Friday 15 November 1991

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Date:	Friday 15 November 1991
Time:	16:00 LT
Type:	PZL-M-18 Dromader
Owner/operator:	Fable Spray Service, Inc.
Registration:	N4506K
MSN:	1Z011-05
Engine model:	WSK PZL-KALISZ
Fatalities:	Fatalities: 0 / Occupants: 1
Other fatalities:	0
Aircraft damage:	Substantial
Category:	Accident
Location:	Florida City, FL - 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:
AFTER MANEUVERING, THE ENG EXPERIENCED A NEAR TOTAL LOSS OF POWER. THE PLT APPLIED FULL THROTTLE BUT THE ENG FAILED TO RESPOND. HE OPENED THE VALVE TO DUMP THE CHEMICAL & WHILE DESCENDING, THE ACFT COLLIDED WITH RISING TERRAIN. THE ACFT THEN CAME TO REST IN A FIELD. EXAM OF THE ENG ASSY REVEALED THAT THE INTAKE MANIFOLD ATTACHED TO THE BOTTOM OF THE OIL SUMP WAS LOOSE. THIS ALLOWED AN EXCESSIVELY LEAN FUEL/AIR MIXTURE WHICH WAS VERIFIED BY VISUAL EXAMINATION OF THE SPARK PLUGS. REVIEW OF THE ENG LOGBOOK REVEALED THAT THE ENG WAS INSTALLED ON APRIL 5, 1989. THERE WERE NO ENTRIES INDICATING THAT THE CARBURETOR ASSY WAS REMOVED SINCE THE ENG WAS INSTALLED.

Probable Cause: PARTIAL LOSS OF ENGINE POWER DUE TO A LOOSE INTAKE MANIFOLD. ALSO, IMPROPER MAINTENANCE BY AN UNKNOWN PERSON.

Accident investigation: