TAME Flight 173

Investigation

Initial fears of a possible sabotage were advanced by the civil aviation authorities after a radio station reported witnesses to a mid-air explosion. During the investigation, this was discarded due to lack of evidence. The civil authorities of aviation initiated an investigation, with cooperation from Boeing, Pratt & Whitney, and the United States National Transportation Safety Board (NTSB).

The investigation results concluded that pilot error was a direct cause of the crash. Several factors were identified: training of the pilots was not properly delivered by TAME for the Boeing 737-2V2 Advanced, the crew was not fully familiar with the controls of the aircraft, and the crew was distracted while trying to locate the runway in heavy fog. As a consequence, the plane went below the minimum safe altitude in a mountainous region, with the flight crew ignoring the voice commands of the ground proximity warning system until seconds before impact.

The training problem emerged due to a lack of compliance with the purchase conditions of the 737, as Boeing reportedly committed to training the pilots for six weeks in Seattle. In addition, the agreements stipulated that after the course, the pilots would begin flying accompanied for one month by an instructor appointed by Boeing. The following month, a foreign safety co-pilot approved by Boeing would join. Finally, only after completing 100 hours of flight would an Ecuadorian pilot be qualified to become commander of the 737. However, for unknown or undeclared reasons, this process was not followed through, and in March 1983 Captain Terán was sent to Brazil to learn to fly jet airplanes in a simulator for only three weeks. In the end, by the time of the accident, Terán had barely 30 flight hours on a Boeing 737.

The above-mentioned distraction factor was compounded by labor problems at the company, as the CVR is reported to have recorded the following quote from the conversation between Captain Terán and First Officer Sommerfeld.

Finally, the airline's military nature, with its corresponding hierarchy, also influenced why Captain Terán, despite being grossly underqualified to fly the 737, had been flying the aircraft. After Terán came back from Brazil in March 1983, he sat on the left in the cockpit seat because, back then, a general could not be "demoted" to co-pilot.