What is the result of the XBLEED pushbutton being in ISOL?

When the XBLEED pushbutton is in the ISOL position, it serves to isolate the left and right bleed air systems from each other. This means that the operation of one bleed air source will not influence the other, allowing for independent management of the bleed air systems. This capability is crucial for achieving efficient aircraft performance and maintaining system integrity, especially in the event of a malfunction in one of the bleed air systems.

Isolating the bleed air sources can prevent cross-contamination or undesired performance impacts that might arise from one system failing or behaving poorly. This means that, while the system is isolated, operators can have better control and can troubleshoot issues without risking system-wide impact on performance and safety.