The Lamia airlines plane that crashed last month near the northwestern city of Medellin, killing 71 people, the majority of them members of Brazil's Chapecoense soccer club, was low on fuel and overloaded, Colombian civil aviation agency Aerocivil said in its preliminary report on the accident Monday.

According to the secretary of aircraft safety at Aerocivil, Col. Fredy Bonilla, on the recordings from the aircraft cabin of the Bolivian airliner, the pilot and copilot are heard talking about possibly making a stop at Leticia, Colombia, or at Bogota, "because they were almost out of fuel," but they finally decided against it.

"They were aware they didn't have enough fuel," the official said, adding that during the flight the pilot, Miguel Quiroga, "decided to land at Bogota but later changed his mind and headed directly for Rionegro," where Medellin's Jose Maria Cordova International Airport is located.

Most of the audio recordings presented Monday were taken from the black box that was examined in London by the manufacturers of the Avro RJ85 aircraft, said Bonilla, noting that "everything is based on evidence."

According to the investigation, according to the flight plan presented by the pilot at Bolivia's Viru Viru International Airport at Santa Cruz de la Sierra, the airliner's period of fuel autonomy was 4 hours, 22 minutes, exactly the same as the flight time, whereas it should have had enough fuel for a longer flight.

"It should have had 1 hour, 30 minutes more (worth of fuel) than the time of the flight," Bonilla said.

The aircraft should also have had a second alternative airport on its flight plan, but it only showed Bogota, the investigation found.

The report further reveals that when the pilot asked the control tower at Jose Maria de Cordova International Airport for permission to land, though his plane was not yet anywhere near the landing field, he neither mentioned how serious the situation was, nor that two of the plane's four motors had stopped working.

Shortly afterwards, with the third motor stopped, the audios revealed Monday that when the control tower asked if some additional service was needed on land for a possible emergency, the pilot said no.

According to the director general of civil aviation, Alfredo Bocanegra, the report presented Monday is not aimed at "determining guilt or responsibility," but rather to prevent further accidents.

The final results of the investigation will be presented in a few months.