Flight 168 was a scheduled domestic service connecting São Paulo to Fortaleza with a stop in Rio de Janeiro. The aircraft, a Boeing 727-212 registered PP-SRK, had completed the São Paulo-Rio leg uneventfully. The flight deck crew were experienced by the numbers: Captain Fernando Antônio Vieira de Paiva, age 43, had more than 15,000 hours in the air. First Officer Carlos Roberto Duarte Barbosa, 28, had over 5,000. The flight engineer, José Erimar de Freitas, 31, had worked at VASP as an aircraft engineer since 1971 - more than a decade on the ground - before qualifying as a flight engineer in 1979; he had about 279 hours in that seat. The aircraft was in working order. The weather over the Ceará coast was dark but flyable. Nothing about the setup, on paper, suggested what was coming.

The 128 passengers were the usual cross-section of an internal Brazilian route in the early 1980s: families, business travelers, students returning to the Northeast. Among them was Edson Queiroz, a prominent businessman from Ceará whose industrial group had helped drive the country's shift from wood-burning to gas stoves. Queiroz had originally been booked on a VARIG flight the following morning, but he worried it would arrive too late for a meeting in Fortaleza. A few minutes before pushback, he exchanged that ticket for a seat on Flight 168. Around him were schoolteachers, engineers, workers finishing trips, relatives returning home. The numbers that matter in an accident like this are not abstractions. They were 137 people - each with a reason to be on that plane, each with someone waiting to meet them in Fortaleza.

From cruise altitude at flight level 330 - about 33,000 feet - the crew was cleared to descend to 5,000 feet for the approach. Fortaleza at night presents a specific visual environment: the bright line of the city stretched along the coast, the dark inland terrain behind it, few intermediate reference points. The 727 descended through its clearance limit and kept going. The co-pilot called out the terrain. The ground proximity warning system sounded twice. The descent continued. At roughly 2,500 feet above sea level, the aircraft flew into the forested flank of a ridge in the Serra da Aratanha and broke up on impact. The first rescuers reached the wreckage early the next morning, after a difficult climb through dense vegetation.

CENIPA, Brazil's aviation accident investigation body, reviewed the flight data and cockpit voice recorders. The conclusion was a specific kind of pilot-error case, one aviation psychologists call a visual illusion on approach. At night, with a bright city lying in front and no clear horizon behind, the lights of Fortaleza could have appeared closer than they were - or lower than the aircraft was - producing a false sense of correct altitude. The captain appears to have trusted that visual picture over the warnings he was being given by his instruments and his crew. This is why ground proximity warning systems exist; two warnings were issued and two went unheeded. The accident became a teaching case in Brazilian aviation training, one of many that would gradually change cockpit culture around the world: when the machine says pull up, you pull up.

The death toll of VASP 168 stood as the worst aviation accident in Brazilian history until the 2006 mid-air collision of Gol 1907 over the Amazon, and later the 2007 runway overrun of TAM 3054 in São Paulo. Today it ranks as Brazil's third-deadliest air disaster and the worst of its twentieth century. A small memorial was built near the crash site in Pacatuba; the Serra da Aratanha is now crossed by hiking trails that pass near the ridge where the 727 came down. VASP itself survived for another quarter-century before collapsing in the 2000s. The lessons from the investigation - about visual illusions, about GPWS authority, about the specific hazards of night approaches to coastal cities - were folded into Brazilian and international training. Flight 168 did not disappear from the record. It became part of what came next.