ppos holding
boeingdream,
the aircraft would remain in the holding pattern until running out of fuel. it happened a few years ago with the helios 737 accident over athens(greece), where the cockpit crew went unconscious due to lack of oxygen because of confusing in mishandling the pressurization system. the plane continued on autopilot & went into a preprogrammed holding until running on empty. the fmc would just put a msg in the scratchpath:" using reserve fuel".
kind regards,
bm