Aeropostal flight 109 originated in Caracas (CCS), Venezuela on a domestic round trip via Porlamar (PMV), Maracay (MYC), Maracaibo (MAR), Santa B rbara del Zulia (STB), and Maracaibo. The flight departed Caracas at 12:05 local time. The first legs of the flight were uneventful. It took off from Maracaibo at 15:58 for the twenty-minute leg to Santa B rbara del Zulia. The cruising altitude of FL165 was reached at 16:04. The controller at Santa B rbara del Zulia cleared the flight to descend to 5500 feet, which was confirmed by the crew. The crew then asked if the VOR/DME at the airport was inoperative, which was denied by the air traffic controller. About 16:15 the descent was arrested. The captain had noticed an erroneous heading selection on the instruments and concluded that they were off course. A climbing right hand turn was flown. The GPWS sounded and a few seconds later, the airplane flew into the side of a fog-shrouded mountain in the La Aguada sector of the p ramo Los Torres. Accident elevation was 9912 feet. PROBABLE CAUSAL FACTORS (translated from original Spanish report): Collision with mountainous terrain while performing a flight in instrument meteorological conditions under visual flight rules (VFR into IMC) following wrong selection of heading or departure radial which the aircraft followed on its way to the destination airport. CONTRIBUTING FACTORS 1. The wrong selection of the departure heading from the Maracaibo Airport; the crew selected a course of 153 instead of 193. 2. Lack of supervision of the pilot in command, contributing to flight acts of indiscipline manifested by the following facts: A) For the modification of flight rules going from visual meteorological conditions (VMC) to instrument flight meteorological conditions (IMC) without appropriate assessment of the geographical position where he was flying. B) Distraction in the cockpit, the result of the conversation between the captain in command of the aircraft and a third person who was there, a male with aeronautical knowledge specific to a pilot. This situation allowed the error in departure radial selection or error or heading to the airport of destination to go unnoticed while performing the checklist called “Taxi Checklist” . C) Also influenced by the act of indiscipline, was the fact that an aircraft ADF frequency was tuned to a commercial station throughout the flight, broadcasting a musical program. 3. Unfavourable weather conditions on the flight, present on site at the time of the incident were crucial in its occurrence. 4. The total lack of interaction between the crew (crew coordination).