Preliminary Investigation of In-Flight Pressurization Issue on LASER Airlines Flight (YV3465)

Incident Overview and Aircraft Details On October 12, 2022, a McDonnell Douglas MD-83 (DC-9-83), registration YV3465, serial number 49452, operated by Linea Aerea de Servicio Ejecutivo Regional (LASER) C.A., departed from Simón Bolívar International Airport (SVMI) in Maiquetía, Venezuela, bound for Las Américas International Airport (MSDS) in Santo Domingo, Dominican Republic. The aircraft was a twin-engine turbofan with Pratt & Whitney JT8D-219 engines, and it carried 103 people on board: two pilots, four cabin crew members, three other crew members, and 94 passengers. ## Sequence of Events The aircraft took off at 15:45 UTC. During initial climb, the captain performed an evasive maneuver to avoid a flock of birds. Shortly after, the cabin crew reported a loud noise beneath the floor near the left front door. The flight crew observed that the cabin was not pressurizing, although no open door or compartment warning light was illuminated; only the flow light was on. The crew followed the Quick Reference Handbook (QRH) procedure for an illuminated flow light and notified air traffic control of their decision to return to SVMI. They requested holding circuits north of the station to reduce weight by burning fuel. The aircraft landed at 16:30 UTC with all passengers unharmed and no reported damage to the aircraft. ## Post-Landing Inspection Upon arrival, investigators found that the main stairway door on the left front door was not fully closed and its securing lever was in the open position. Because this compartment is pressurized and communicates with the electronics compartment, the door was secured and a pressure test was conducted. The test confirmed that the only pressure leak was at the improperly closed stairway door. ## Identified Non-Conformities The inspection revealed three non-conformities: 1. The cockpit warning light did not illuminate when the stairway door was open. 2. The cabin crew front control panel warning light did not illuminate when the stairway door was open. 3. The mechanical locking system for the stairway door with the main door closed was not functioning, and the locking arm was of the incorrect size. ## Preventive Measures The Venezuelan Civil Aviation Accident and Incident Investigation Board (JIAAC) issued preliminary preventive measures to LASER Airlines, requiring the activation of the warning lights in both the cockpit and cabin crew panel to ensure the crew is informed of compartment malfunctions. The board also required the installation of the correct locking arm in accordance with the manufacturer's manual to prevent the deactivation of the securing hooks and avoid unsafe operations. ## Investigation Status The investigation was in the development and execution phase, with technical, operational, and documentary analysis ongoing for the final report. The preliminary information was subject to change and potential errors. The incident was reported to the ICAO ADREP system, and the United States, as the state of design and manufacture, was notified. The NTSB responded by assigning an accredited representative. All times in the report are in UTC.