Incident Overview
The aircraft, while en route to its cruising altitude, ceased its climb at flight level 330 (FL330) when the flight crew determined that the pressurization system was not functioning correctly. The crew noticed abnormal cabin altitude readings and initiated standard procedures.
Pressurization Indications
During the climb, the cabin rate of climb indicator showed +500 feet per minute, indicating a rise in cabin altitude. The cabin altitude index displayed 8.0, and the differential pressure reading was 5.0. Within a few seconds, the cabin altitude index increased to 10.0, signaling a further loss of pressurization.
Crew Actions
The flight crew performed the applicable Quick Reference Handbook (QRH) procedures for the pressurization anomaly. They donned oxygen masks and instructed passengers to do the same. The aircraft was subsequently returned to Rio de Janeiro/Galeão International Airport (SBGL). The landing was executed without incident, and no damage to the aircraft or injuries to occupants were reported.
Investigation
The investigation is being conducted by the Brazilian Aeronautical Accident Investigation and Prevention Center (CENIPA). Inquiries regarding the incident should be directed to that authority. No further details have been released at this time.