Loss of control Accident de Havilland Canada DHC-6 Twin Otter 100 N157KM,

ASN Wikibase Occurrence # 321158

Date:	Tuesday 8 March 2011
Time:	11:40
Type:	de Havilland Canada DHC-6 Twin Otter 100
Owner/operator:	Desert Sand Aircraft Leasing
Registration:	N157KM
MSN:	57
Year of manufacture:	1967
Total airframe hrs:	16541 hours
Cycles:	20927 flights
Engine model:	Pratt & Whitney Canada PT6A-27
Fatalities:	Fatalities: 2 / Occupants: 2
Aircraft damage:	Destroyed, written off
Category:	Accident
Location:	1,3 km SW of Clayton County Airport-Tara Field, GA - United States of America
Phase:	Approach
Nature:	Test
Departure airport:	Clayton County Airport-Tara Field, GA
Destination airport:	Clayton County Airport-Tara Field, GA
Investigating agency:	NTSB
Confidence Rating:	Accident investigation report completed and information captured

Narrative:
A DHC-6 Twin Otter skydiving plane was destroyed when it crashed during a local post-maintenance test flight from Clayton County Airport-Tara Field, GA.
The airplane came down in trees and broke up, killing both occupants.
The accident flight was the first flight after both of the airplane's Pratt & Whitney Canada PT6A-20, 550-horsepower engines, were replaced with PT6A-27, 680-horsepower engines. The airplane took off with a pilot and a pilot-rated mechanic on board. Two uneventful touch-and-go landings were completed.
The airplane was then observed flying in the traffic pattern for runway 6. An eyewitness reported that the airplane was "struggling to gain altitude and airspeed." As the airplane turned to line-up with the runway, it "stalled" and descended nose first toward the ground.
The airplane impacted trees in a wooded marsh area, short of the threshold, near the extended centerline of runway 6. The airplane came to rest about 80-degrees vertically and canted about 25-degrees on the right wing.

PROBABLE CAUSE: "The pilot did not maintain airspeed while maneuvering, which resulted in an aerodynamic stall."

Accident investigation: