The manager of regulatory compliance for the operator reported that a service truck had impacted the airplane, which resulted in substantial damage to the left wing. He added that the first officer was on the ground and that the captain was in the terminal at the time of impact. The Federal Aviation Administrator (FAA) inspector reported that the flight crew reported that the captain was on-board the airplane and that the first officer was on the ground at the time of impact. The airplane was scheduled to depart in 1 hour, and they were preparing to fuel the airplane. The FAA inspector added that the service truck driver reported that he was crossing the taxiway on the zipper road, and as he approached the main terminal road, a bag cart tug pulled out in front of him, causing him to swerve into the parked airplane. The airplane sustained substantial damage to the left wing. The manager reported that there were no preaccident mechanical failures or malfunctions with the airplane that would have precluded normal operation.