Accident Cessna 421C N6205X, Saturday 14 April 1984

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Date:	Saturday 14 April 1984
Time:	23:50 LT
Type:	Cessna 421C
Owner/operator:	Aztec Well Servicing Co.
Registration:	N6205X
MSN:	421C0901
Total airframe hrs:	1380 hours
Engine model:	Continental GTSIO-520-N
Fatalities:	Fatalities: 0 / Occupants: 2
Other fatalities:	0
Aircraft damage:	Substantial
Category:	Accident
Location:	Farmington, NM - United States of America
Phase:	Taxi
Nature:	Executive
Departure airport:	Odessa, TX (EO2)
Destination airport:
Investigating agency:	NTSB
Confidence Rating:	Accident investigation report completed and information captured

Narrative:
WHILE TAXIING AFTER LANDING, THE ACFT WAS IN A LEFT TURN WHEN THE RIGHT MAIN GEAR COLLAPSED. THE PLT REPORTED THAT ALL 3 GEAR INDICATED DOWN & LOCK, BOTH BEFORE & AFTER THE MISHAP. AN EXAM OF THE RIGHT MAIN GEAR ACTUATOR, PN 9910136-4, REVEALED THAT CONTAMINATION HAD COLLECTED ON THE INNER CYLINDER WALL & PREVENTED THE KEYS FROM PROPERLY EXTENDING TO THE LOCKED POSITION. ALSO, THE GEAR SYS WAS DESIGNED TO MAINTAIN HYDRAULIC PRESSURE ON THE DOWN SIDE OF THE ACTUATOR WHEN IT WAS EXTENDED. HOWEVER, THE CONTAMINANT ALSO PREVENTED THE SWITCH (IN THE ACTUATOR) FROM OPERATING PROPERLY.

Probable Cause:

Accident investigation: