What happened
During a flight segment from PPRF to PPKG, the aircraft was cleared to maintain an altitude of 1,800 metres. However, upon reaching the Nazaré position, the pilot performed an unauthorized descent to 1,200 metres. The aircraft subsequently passed over the PPKG facility at an altitude of only 1,000 metres, which was 200 metres below the minimum altitude required by the Directorate of Air Routes for initiating the standard procedure.
Following this descent, the pilot reviewed the approach procedures for PPKG. Despite a suggestion from the copilot regarding the management of the procedural documentation, the pilot proceeded based on memory. The crew initiated an approach that deviated from approved charts, flying on a heading that was not identified by investigators until the aircraft reached 520 metres. At this stage, the aircraft was already below the critical altitude of 647 metres.
Although the crew established vertical visual contact with the runway, they had already passed the critical point and were positioned directly over the runway. In an attempt to maintain visual contact with the landing strip, the pilot attempted to enter the traffic pattern. This maneuver failed during the final approach phase. While flying on a heading of 200 degrees, the aircraft began a descent, signaled by the activation of the aircraft lights. The copilot attempted to regain visual references through the window but was unable to do so before a violent impact occurred. The accident resulted in 13 fatalities and 5 serious injuries.
Findings
Investigations revealed that the flight path followed by the pilot did not align with the official approach charts approved by the Directorate of Air Routes. Additionally, while the crew established visual contact at a low altitude, the aircraft was only approximately 40 metres above the ground at that moment. Although meteorological data from the Loide station indicated a ceiling of 130 metres and visibility of 6 km, improper adherence to established flight procedures was a primary factor in the sequence of events.