Narrative:The aircraft, an EC-47, was assigned to the 361st Tactical Electronics Warfare Squadron. It operated a normal classified combat sortie under call sign Baron 56. The flight was cleared for takeoff by the tower at Nakhon Phanom, Thailand at 10:44.
The co-pilot made the right seat takeoff with the aircraft commander in the left seat. Takeoff, climb out, and level off at 10,000 feet were normal and a normal, uneventful tactical mission was flown.
After the mission, the aircraft proceeded to Nakhon Phanom and entered the GCA pattern at 17:00. The weather at the base was 5,000 feet scattered, 10,000 feet scattered with winds 070 degrees variable three to seven knots. The co-pilot made two uneventful GCA precision low approaches: after the second low approach the aircraft commander took control of the aircraft and requested and received permission to enter a left-closed downwind. The VFR approach was normal and the tower cleared Baron 56 to land calling the winds at 070 degrees at seven knots. According to statements from crewmembers, the touchdown was normal with perhaps a slight bounce, but the aircraft then began a gradual movement to the left, nearly departing the runway; the aircraft commander applied high power to the left engine and the aircraft then swerved sharply to the right, departing the right hand side of the runway approximately 1800 feet from the approach end at a 45 degree angle.
Power was applied to go-around. The airplane crossed a ditch, and became airborne after the right main landing gear struck the west (far) side of the ditch embankment. After becoming airborne the aircraft cut a wire to the base perimeter lights and also contacted a tree along the west base perimeter. Apparently some damage was done to the Number One (left) propeller or engine since the third pilot, sitting in the flight engineer's seat noticed that the propeller disc was erratic instead of flat as it is normally. Also, other crewmembers thought the Number Two propeller or engine was not functioning properly, causing vibration, and noticeable slowing down. All crewmembers recall vibrating or knocking throughout the airframe at approximately this time; the aircraft was momentarily in a shallow left bank attempting to clear the trees and parallel the runway.
Approximately three fourths of the way down the runway a shallow right turn was begun and the aircraft commander, who had noted a power loss of failure of the Number Two engine ordered the Number Two engine feathered. The aircraft was just above the trees at this point still in a shallow right turn. The navigator thinks he heard the co-pilot acknowledge the order to feather the Number Two engine. The aircraft commander then initiated the emergency procedure for engine failure by stating "throttle - closed" and at approximately this time the third pilot states he saw the Number one propeller slow down and a blade pitch change occur. Also crewmembers agree that at this point no sound of engine power was heard from either engine. According to the third pilot, the aircraft commander told the co-pilot "you feathered the wrong one, you feathered Number One," followed shortly by "Bring it in, bring it in." Shortly after this, at 17:40, the aircraft impacted the trees and crashed.
» Thai Aviation History website
» Vietnam Air Losses : United States Air Force, Navy and Marine Corps fixed-wing aircraft losses in Southeast Asia 1961-1973 / Chris Hobson
This information is not presented as the Flight Safety Foundation or the Aviation Safety Networkĺs opinion as to the cause of the accident. It is preliminary and is based on the facts as they are known at this time.