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| Date: | Thursday 1 December 2022 |
| Time: | |
| Type: |  Airbus A330-202 |
| Owner/operator: | Iberia |
| Registration: | EC-MLP |
| MSN: | 1740 |
| Year of manufacture: | 2016 |
| Engine model: | GE CF6-80E1A4 |
| Fatalities: | Fatalities: 0 / Occupants: 215 |
| Other fatalities: | 0 |
| Aircraft damage: | None |
| Category: | Incident |
| Location: | Montevideo FIR -
 Uruguay
|
| Phase: | En route |
| Nature: | Passenger - Scheduled |
| Departure airport: | Montevideo-Carrasco Airport (MVD/SUMU) |
| Madrid-Barajas Adolfo Suárez Airport (MAD/LEMD) | |
| Investigating agency: | CIAIA |
| Confidence Rating: |  Accident investigation report completed and information captured |
Iberia Airlines flight IB6012, an Airbus A330-202, was climbing normally along airway UM540, about 30 minutes after departure from MVD, established at flight level 350, when the crew noticed the "CAB ALT" (Cabin Altitude) warning flashing on the CAB PRESS system page.
The cabin was ascending at about 300 feet per minute, the outflow valves (which control the release of air to maintain cabin pressurization) were fully closed, there were no door noises indicating a loss of pressurization, and the bleed valves (which supply air for pressurization) were functioning normally.
The cabin’s barometric altitude exceeded 9,550 feet, triggering the ECAM warning "CAB PR EXCESS CAB ALT" along with the Master Warning light and a continuous repetitive aural alarm. In response, the crew donned their oxygen masks.
The failure was detected while the aircraft was still in Uruguayan airspace, although air traffic control responsibility had already been transferred to Brazil. The aircraft continued its flight path and entered the airspace of the Brazil, at which point the crew issued a "PAN PAN PAN" message to Curitiba air traffic control, requesting an immediate descent.
After the aircraft descended to approximately 25,000 feet, the high cabin pressure condition resolved.
The crew maintained contact via SATCOM with the operator’s flight monitoring center.
Two attempts were made to climb again, but as the aircraft gained altitude, the cabin altitude also rose uncontrollably, regardless of whether the Cabin Pressure Controller (CPC) was set to automatic or manual mode.
Coordination was made with Curitiba air traffic control for a descent to FL120 and a return to the point of origin, MVD, canceling the "PAN PAN PAN" message, with coordination also carried out with the operator.
The aircraft landed at 20:09 hours on runway 25 at MVD, with a weight exceeding the maximum landing weight, but completed the arrival without incident.
CONCLUSIONS
Chain of events leading to the occurrence
The bellows connecting the condenser outlet to the duct carrying air to the mixing unit, a component of the air conditioning system, was improperly installed.
During the pressurization failure that occurred the day before the event, the air leak was not detected.
The aircraft resumed service on 5 December 2022.
Accident investigation:
 |
|
Sources:
CIAIA
Revision history:
| Date/time | Contributor | Updates |
|---|---|---|
| 06-Apr-2025 18:03 | ASN | Added |
| 06-Apr-2025 18:12 | ASN | Updated [Narrative, ] |
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