Accident de Havilland Canada DHC-6 Twin Otter 100 N656WA,

Date:	Wednesday 18 June 2008
Time:	10:01
Type:	de Havilland Canada DHC-6 Twin Otter 100
Owner/operator:	Wiggins Airways
Registration:	N656WA
MSN:	47
Year of manufacture:	1967
Total airframe hrs:	38185 hours
Engine model:	Pratt & Whitney Canada PT6A-20
Fatalities:	Fatalities: 1 / Occupants: 1
Aircraft damage:	Destroyed, written off
Category:	Accident
Location:	Hyannis-Barnstable Airport, MA (HYA) - United States of America
Phase:	Take off
Nature:	Cargo
Departure airport:	Hyannis-Barnstable Airport, MA (HYA/KHYA)
Destination airport:	Nantucket Memorial Airport, MA (ACK/KACK)
Investigating agency:	NTSB
Confidence Rating:	Accident investigation report completed and information captured

Narrative:
Wiggins Airways has a twice daily flight to the Nantucket Memorial Airport, MA (ACK) carrying UPS and Federal Express packages. It was carrying about 200 pounds of cargo for the morning flight out of Hyannis-Barnstable Airport, MA (HYA). The airplane taxied to runway 24 for departure. According to an eye witness the pilot made a rolling takeoff. The airplane banked left immediately after takeoff. It then struck terrain in a steep bank.
Investigation results indicate that the upper flight control lock was still attached to the column by its removable pin. The pin attaching the upper control lock to the control column remained tethered to upper flight control lock by a steel cable. However, the pins from the two other flight control lock cables were missing, and the cables exhibited pin retaining end failures consistent with overstress.

PROBABLE CAUSE: "The pilot's failure to remove the flight control lock prior to takeoff. Contributing to the accident was the Federal Aviation Administration's failure to issue an airworthiness directive making the manufacturer's previously-issued flight control lock service bulletins mandatory."

Accident investigation: