The TACA Viscount took off from Las Mercedes Airport for a flight to San Salvador Guatemala, Mexico and New Orleans. Shortly after lift-off the no. 1 engine was observed to have stopped. The aircraft started an abrupt left turn followed by an excessive bank to the left. The plane lost height, collided with a tree and crashed inverted. PROBABLE CAUSE: “In accordance with the documentation obtained and data collected during the inquiry, the Investigating Board reached the following conclusions: The accident was caused by the following factors: 1) Failure of No.1 engine at the end of runway 29 during takeoff and before reaching V2 speed. 2) The non-retraction of the landing gear immediately after the aircraft reached V2 speed; 3) Failure of engine no.2 a few seconds later, during a climb with insufficient speed to maintain control which resulted in a forced turn to the left that became tighter and tighter; the aircraft finally rolled into an inverted position and hit a tree with its left wing. Several possible reasons for the failure of engines no.1 and 2 and the non-retraction of the landing gear were considered, however the Board found no substantiating evidence or proof in the various tests carried out on the aircraft’s parts to support any one of them. The Board was therefore, unable positively to attribute the accident to any mechanical or electrical failure or to any piloting error.”