Trip No. 9 departed from Santiago, Chile at 05:30 with Lima, Peru as its destination. The flight arrived at Arequipa, Peru at 13:59 for an intermediate stop. It left Arequipa at 14:09. At 14:25, the captain reported to Arequipa that the flight was “leaving control zone altitude 12,200, climbing on instruments, course 290.” Fifty minutes later, the DC-3 struck a mountain peak at an elevation of about 13,000 feet. PROBABLE CAUSE: “Action of the pilot in continuing the flight on instruments in the overcast, contrary to company flight procedure of which, according to the evidence, the pilot was aware. CONTRIBUTING FACTORS: 1. Absence of adequate flight dispatch control by the company.; 2. Failure of the company to inaugurate and maintain written flight and operating procedures in such a form as to be constantly available for the guidance of pilots and dispatchers.”