These planes all come with handbooks that the manufacturer provides for anomalous situations, like when some landing gear don't work. Once the flight crew run t

These planes all come with handbooks that the manufacturer provides for anomalous situations, like when some landing gear don't work. Once the flight crew run through the checklists in the handbooks for the problem, that's pretty much it. In certain cases and time permitting, the crew might also be in contact with their airline's maintenance/engineering staff in case there's something else that might be done. But once those options are exhausted there's no point in staying in the air, and these checklists can generally be done fairly quickly by a trained crew.