Flight 222 to Quito departed Guayaquil at 08:06. Some 13 minutes later the crew reported an ETA over the Manta intersection of 08:41. One minute later the pilot reported at 4000 feet and said they were maintaining this altitude. Further climb clearance was requested and which was granted at 08:40. At 08:41 the crew reported overhead the Manta beacon at 5000 feet and a Quito ETA of 09:16. Last contact with the flight was when it was cleared to climb above the clouds. At an altitude of 7500 feet the aircraft flew into Mount Illiniza in the Chugchilan mountain range. PROBABLE CAUSE: “The pilot did not follow he 358deg Guayaquil-Esmeraldas track, authorised for instrument flight, until clear of cloud, but probably assumed a heading of 25deg as soon as he left Guayaquil, in order to fly the most direct route between Guayaquil and Quito. In so doing while on instruments, he deviated from the Guayaquil-Esmeraldas track at too low an altitude to clear the Chugchilan range, before him with an adequate safety margin.”