What happened
On November 17, 2018, a Boeing 737-86J, registration LV-HFR, operated by FB Líneas Aéreas S.A. (Flybondi), was performing a scheduled commercial flight from Iguazú to El Palomar. While cruising at flight level 360 near Paso de los Libres, Corrientes, the aircraft experienced a sudden cabin depressurization.
Upon the activation of the cabin altitude warning, the flight crew immediately initiated emergency procedures. The captain instructed the crew to don oxygen masks and directed an emergency descent. The pilots communicated with air traffic control to request a descent to 10,000 feet. During the descent, the crew manually manipulated the pressurization mode selector and the outflow valve to stabilize the cabin. Once the aircraft reached 10,000 feet and the cabin altitude was controlled, the crew continued the flight to the destination, landing without further incident. There were no injuries among the 143 passengers and 7 crew members.
The investigation
The Argentine Transportation Safety Board (JST) examined the flight data, cockpit voice recorder, and maintenance records. The investigation focused on the technical cause of the depressurization, the crew's operational performance, and the maintenance of the aircraft's air conditioning and pressurization systems. The JST also reviewed the airline's training programs and the adequacy of emergency signage and automated announcements.
Findings
- The primary cause of the incident was a cabin depressurization during the cruise phase.
- The investigation identified several systemic safety risks, including the fact that emergency signage on the aircraft was only available in Turkish, German, and English, failing to meet local regulatory requirements for Spanish-language signage.
- Automated passenger address (PA) announcements were also not provided in Spanish.
- Discrepancies were found in the airline's operations manual regarding center of gravity calculations and the identification of memory items in abnormal procedure lists.
- The investigation noted that the airline's training program for the Boeing 737-800 did not explicitly include cabin depressurization or emergency descent maneuvers in the initial simulator training requirements.