What happened
On August 7, 2023, at 11:20 UTC, a Boeing 737-401, registration YV3158, operated by Avior Airlines, was climbing through 11,000 feet en route from Barcelona (SVBC) to Maiquetía (SVMI). The flight was carrying 101 passengers and 5 crew members. During the climb, the flight crew noticed an audible noise indicating a pressurization leak near the R1 window (co-pilot side). As the aircraft continued to ascend, the intensity of the noise increased, and the crew observed that part of the R1 window seal had become exposed.
Before reaching 14,000 feet, the captain notified Maiquetía Area Control Center of the intention to return to the departure airport. The flight attendant chief informed the captain that the passenger cabin oxygen masks had not deployed. The aircraft subsequently returned to Barcelona and landed safely on Runway 15. There were no injuries to the passengers or crew, though the aircraft sustained the aforementioned technical fault.
The investigation
Investigators examined the aircraft' and conducted inspections following specific maintenance tasks. A pressure test was performed on the cabin, which confirmed noise at the lower right corner of the R1 window. Maintenance personnel then applied torque to the securing bolts according to manufacturer specifications and performed a subsequent pressurization test, which yielded satisfactory results.
Findings
- The R1 window seal had become detached due to inadequate installation regarding the torque applied to the securing bolts, failing to meet maintenance manual requirements.
Safety action
- The maintenance organization (OMAC-N 440 Avior Airlines) is required to conduct recurrent training for all maintenance technicians and personnel responsible for fleet maintenance to ensure strict adherence to manufacturer maintenance manuals.