What happened
On February 26, 2023, a McDonnell Douglas DC-9-81, registration YV1243, operated by LÍNEA AÉREA DE SERVICIO EJECUTIVO REGIONAL, C.A. (LASER), departed from El Vigía's Juan Pablo Pérez Alfonso International Airport at 18:44 UTC. The flight was bound for Maiquetía's Simón Bolívar International Airport with 98 people on board, including the crew and 90 passengers.
While cruising at FL330, approximately 40 NM from the Barquisimeto VOR (SVBM) at 19:15 UTC, the flight crew observed a cabin altitude alert indicating a loss of pressure. The crew immediately implemented the Quick Reference Handbook (QRH) procedures, donned oxygen masks, and requested an emergency descent from Maiquetía Area Control Center. The aircraft descended to FL110, where cabin pressurization stabilized. The flight continued without further incident, landing safely at 19:41 UTC with no injuries and no damage to the aircraft.
The investigation
The JIAAC investigation included a visual inspection of the air conditioning and engine systems conducted by the maintenance organization (OMAC N° 475). Technicians tested the pressurization control boxes in the electrical/electronic compartment and performed pressure tests using both the APU and both engines; no leaks were detected during these procedures.
During the inspection, investigators noted that while the pilot and co-pilot emergency masks remained sealed in their original packaging, the deployment switch brake for the passenger oxygen masks was broken. Following the inspection, the maintenance organization replaced the broken mask deployment switch brake and, as a preventive measure, replaced the automatic pressure control module on the upper panel and the Pressurization Control Box #2.