What happened
On July 8, 2008, a Boeing 757, registration G-MONC, operated by Monarch Airlines, was performing a passenger flight approaching Faro Airport. During the approach phase, the aircraft's pneumatic system experienced a failure on the left side, which triggered a "LEFT BLEED OVER FLOW" alert in the cockpit.
The investigation
Following the occurrence, maintenance personnel inspected the aircraft and identified damage to the pneumatic duct located along the leading edge of the left wing. The inspection also revealed that the associated thermal insulation had been damaged. Due to the nature of the damage, the operator contacted its headquarters to arrange for the necessary repair materials to be delivered to the site.
Because the aircraft was registered in the United Kingdom, the GPIAAF notified the UK Air Accidents Investigation Branch (AAIB) of the incident and shared all collected information. The investigation was subsequently closed after no further requests for assistance were received from the AAIB.