Overview
• Operator: Wizz Air
• Aircraft Model: Airbus A321-200
• Registration: HA-LTK
• Flight Number: W4-3176
• Route: Barcelona (Spain) → Bucharest Otopeni (Romania)
• Date: 4 February 2025
• Occupants: Unspecified
• Nature of Incident: Cabin pressure problem leading to an emergency descent
Incident Summary
Wizz Air flight W4-3176, operated by an Airbus A321-200 (HA-LTK), was cruising at FL330 approximately 140 nautical miles west-southwest of Bucharest, still within Bulgarian airspace, when the crew identified a cabin pressure issue. The aircraft began an emergency descent in a circular pattern before crossing into Romanian airspace, eventually leveling off at FL120 and later FL100.
During the descent, the cabin altitude exceeded 14,000 feet, prompting the crew to don oxygen masks and deploy passenger oxygen masks as a precaution. The Mayday call was initially cancelled upon reaching a stable altitude, but on approach to Bucharest Otopeni, the crew redeclared Mayday due to a passenger (female, 32) requiring medical attention. The aircraft landed safely on runway 08R approximately 35 minutes after leaving FL330.
Sequence of Events
Cruise Phase (FL330)
• The crew detected an issue with cabin pressurization while flying at FL330.
• The aircraft initiated an emergency descent, circling within Bulgarian airspace before crossing into Romania.
Emergency Descent
• The cabin altitude exceeded 14,000 feet, triggering the deployment of passenger oxygen masks.
• The crew donned oxygen masks and performed a controlled descent to FL120.
• The Mayday call was initially cancelled after stabilizing at FL100.
Approach & Medical Emergency
• During the final approach to Bucharest Otopeni, the crew redeclared Mayday, reporting a passenger (32-year-old female) required medical attention.
• The aircraft landed safely on runway 08R and was met by emergency services.
Post-Landing & Aircraft Status
• The aircraft remained grounded in Bucharest for further inspection and investigation.
• As of 5 February 2025, the aircraft is still on the ground.
Investigation Findings & Safety Implications
Bulgaria’s AIB Statement (14 February 2025)
• The incident has been classified as a “serious incident” and is under investigation.
• The crew identified a cabin pressure issue at FL330 and attempted to manage the situation before performing an emergency descent.
• The cabin altitude exceeded 14,000 feet, triggering the automatic deployment of passenger oxygen masks.
• The aircraft descended to FL100, at which point the emergency was cancelled.
• The passenger’s medical condition is currently unknown, but the aircraft was met by medical personnel upon landing.
Potential Causes & Technical Analysis
1. Aircraft Pressurization System Failure
• A malfunction in the cabin pressure control system could have led to the gradual loss of pressurization.
• Possible failure of the outflow valve, pressure sensors, or air conditioning packs.
2. Structural Integrity Issue
• A slow cabin decompression might indicate a minor fuselage leak or door seal failure.
• However, no reports suggest explosive decompression or structural damage.
3. Crew Response & Handling
• The crew correctly identified the issue, initiated an emergency descent, and followed standard safety procedures.
• The deployment of passenger oxygen masks was a precautionary measure and aligns with best practices.
Safety Recommendations & Preventative Measures
• Thorough inspection of the aircraft’s pressurization system, including:
• Outflow valves
• Air conditioning packs
• Door seals and structural integrity
• Enhanced monitoring of pressurization trends during flight operations to detect early signs of failure.
• Review of crew training for handling pressurization anomalies, ensuring rapid recognition and response to minimize passenger impact.
Disclaimer
This report is based on available information as of 14 February 2025. While every effort has been made to ensure accuracy, the completeness of the details cannot be guaranteed. If you are the rightful owner of any referenced materials and wish them removed, please email takedown@cockpitking.com.
