Serious incident Fairchild SA227-AC Metro III N446MA, Monday 30 August 1993

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Date:	Monday 30 August 1993
Time:	13:30 LT
Type:	Fairchild SA227-AC Metro III
Owner/operator:	Mesaba Airlines
Registration:	N446MA
MSN:	AC-693
Year of manufacture:	1987
Total airframe hrs:	11069 hours
Engine model:	GARRETT TPE-331-11U
Fatalities:	Fatalities: 0 / Occupants: 2
Other fatalities:	0
Aircraft damage:	None
Category:	Serious incident
Location:	Grand Rapids, MN - United States of America
Phase:	Manoeuvring (airshow, firefighting, ag.ops.)
Nature:	Executive
Departure airport:	Thief Rve Falls, MN (TVF
Destination airport:
Investigating agency:	NTSB
Confidence Rating:	Accident investigation report completed and information captured

Narrative:
THE FLIGHT CREW WAS ON A REPOSITIONING FLIGHT. THE CREW EXPERIENCED A RESTRICTION TO AILERON CONTROL WHILE MANEUVERING TO LAND. ON APPROACH TO LANDING THERE WAS LIMITED AILERON CONTROL TO THE LEFT, AND NO AILERON CONTROL TO THE RIGHT. THE AIRPLANE LANDED SUCCESSFULLY. SUBSEQUENT EXAMINATION OF THE AILERON CABLE DISCLOSED THAT IT WAS BROKEN. AN INDEPENDENT METALLURGICAL EXAMINATION OF THE CABLE REVEALED THAT THE FAILURE WAS CONSISTENT WITH IT HAVING COME OFF THE PULLEY AND WEARING AGAINST A SMALL DIAMETER STEEL PIN. AFTER THE INCIDENT, A COMPLETE INSPECTION OF THE AIRLINE'S FLEET WAS CONDUCTED ON THE AILERON CONTROL CABLES AND NO SIMILAR DISCREPANCIES WERE FOUND.

Probable Cause: the fractured aileron cable and other maintenance personnel's inadequate maintenance/adjustment.

Accident investigation: