What happened
On March 4, 2022, at 17:05 UTC, a Boeing 737-800, registration LV-FXQ, operated by Aerolíneas Argentinas, experienced a rapid cabin depressurization during a scheduled commercial flight. The aircraft was cruising at flight level 360 near Recreo, Santiago del Estero, en route from Córdoba to Salta.
Upon the activation of the cabin altitude warning, the flight crew immediately initiated emergency procedures. The crew donned oxygen masks and transitioned the pressurization system to manual mode to stabilize the cabin. Following the incident, the pilots declared a 'MAYDAY' to Córdoba Air Traffic Control and executed an emergency descent, eventually returning to the departure airport in Córdoba. There were no fatalities and no serious injuries among the 145 people on board, though one passenger sustained minor injuries.
The investigation
The investigation conducted by the Argentine Transportation Safety Board (JST) focused on the technical performance of the aircraft's pressurization system and the crew's response. Investigators analyzed the Flight Data Recorder (FDR) and Cockpit Voice Recorder (CVR) to reconstruct the sequence of events.
Technical examination of the aircraft's outflow valve (OFV) mechanism was performed. The investigation looked into the electrical signals and mechanical operation of the valve, specifically examining the 28V DC power supply and the manual control switches on the air conditioning panel. The investigation also reviewed the flight crew's training records, noting that the captain had recently completed simulator training that specifically included emergency procedures for cabin altitude warnings and rapid depressurization.