Flight Y4-3519 | Registration: XA-VVB
Date: 2 April 2025 | Location: Near Queretaro, Mexico
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Introduction
On 2 April 2025, a Volaris Airbus A320-200, registration XA-VVB, operating scheduled passenger service Y4-3519 from Queretaro Intercontinental Airport (MMQT) to Cancun International Airport (MMUN), experienced a sudden loss of cabin pressure while climbing to cruising altitude. Shortly after levelling at FL390, the crew initiated an emergency descent to FL100, deployed passenger oxygen masks, and declared a return to Queretaro.
The aircraft landed safely approximately 85 minutes after initial departure. No injuries were reported among passengers or crew. A replacement aircraft was dispatched, reaching Cancun with a delay of over five hours.
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Flight Details
• Aircraft Type: Airbus A320-232
• Engines: 2 × IAE V2527-A5
• Operator: Volaris
• Tail Number: XA-VVB
• Flight Number: Y4-3519
• Departure Airport: Queretaro Intercontinental Airport (MMQT)
• Destination Airport: Cancun International Airport (MMUN)
• Date of Incident: 2 April 2025
• Phase of Flight: Cruise (Initial level-off at FL390)
• Occupants: Estimated 170 (passengers and crew combined)
• Time of Occurrence: Approx. 12:00 local time
• Oxygen Mask Deployment: Yes
• Aircraft Ground Time Post-Incident: ~17.5 hours (as of 3 April 2025)
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Sequence of Events
Climb and Onset of Pressurisation Failure
The A320 departed Queretaro normally and climbed towards its cruising altitude. Upon levelling at FL390, flight crew received indications of cabin pressure loss. Rapid depressurisation was suspected due to the automatic deployment of oxygen masks throughout the passenger cabin.
Emergency Descent
In accordance with Airbus emergency procedures, the crew immediately initiated a descent to 10,000 feet, where breathable oxygen levels could be sustained without supplemental oxygen systems. The rate of descent and flight data parameters are under review, though no indications of erratic descent or further mechanical issues have been reported.
Air Traffic Control was notified, and the crew declared an emergency (likely squawking 7700), requesting priority handling for return to Queretaro.
Safe Return and Landing
The aircraft completed the emergency descent, stabilised at FL100, and returned to MMQT. The landing was uneventful, with emergency services on standby. After touchdown, the aircraft taxied to the apron under its own power.
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Technical and Operational Analysis
Pressurisation System Overview
The Airbus A320 is equipped with an automatic cabin pressure control system, typically comprising:
• Cabin Pressure Controllers (CPCs)
• Outflow Valves
• Safety valves (overpressure and negative pressure relief)
• Cabin altitude indicators
Possible failure points include:
• Malfunction of CPCs or pressure sensors
• Faulty outflow valve operation
• Structural failure or door seal leaks
Given the deployment of passenger oxygen masks, the depressurisation was likely significant enough to cross the threshold of cabin altitude >14,000 ft, triggering automatic oxygen release.
Maintenance and Follow-up
Initial inspections are likely focused on:
• Fault codes from the ECAM (Electronic Centralised Aircraft Monitoring)
• Pressurisation logs from the Flight Data Recorder
• Physical examination of pressure seals, valves, and air conditioning packs
The aircraft remains grounded as of 3 April 2025 while Volaris maintenance teams and Mexican civil aviation authorities conduct an investigation.
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Replacement and Passenger Handling
• Replacement Aircraft: XA-VLO (A320-200)
• Delay to Destination (Cancun): ~5 hours 20 minutes
• Passenger Care: Volaris provided rebooking and refreshments during the delay. No medical emergencies were reported, though some passengers described mild discomfort or stress during the oxygen mask deployment.
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Summary and Safety Considerations
This event underscores the importance of crew readiness and system redundancy during high-altitude operations. Rapid depressurisation, although rare, presents immediate risks including hypoxia, system malfunctions, and passenger panic.
In this case, the crew responded swiftly and in accordance with Airbus emergency protocols. The safe outcome—with no reported injuries—demonstrates the effectiveness of training and aircraft safety systems.
Volaris and aviation safety investigators are expected to issue a full report following their internal review.
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Disclaimer
This report is based on publicly available information as of 3 April 2025. It is subject to revision pending the outcome of any official investigation. If you are the rightful owner of any content or material used in this report and wish it to be removed, please contact takedown@cockpitking.com.
