Since September 11, 2001, the air transports of the U.S. Air Force Air Mobility Command (AMC) have moved 445,000 tons of cargo and 447,000 passengers to Afghanistan and the Persian Gulf. Some 54 percent of that traffic went through the U.S. military air base of Rhein-Main (next to the Frankfurt, Germany airport.) The aircraft used include both military and leased commercial transports. This is the first major war for the new C-17 transport. Built to move over oceans, but still able to land on primitive airfields, the C-17 pilots have learned a lot about operating under rough conditions. In Afghanistan, the C-17s were sometimes fired on. Many C-17 crews can now land and take off using Night Vision Goggles. Even the ground crews loading and loading the C-17s have used Night Vision Goggles, as lighting up just makes the C-17s a better target at night. The air force is setting a "tactics school" for C-17 crews similar to the one for C-130 pilots. The smaller, prop driven C-130 has long been the principal tactical transport. But the C-17 is now sharing some of that load. In the past, large transports had to land a better equipped air bases and shift their cargo to C-130s for the final run to front line air fields. But now, in many cases, stuff can be brought in directly, from North American airports to front line airfields, on C-17s. Operating in Central Asia also caused many C-17s to have additional fuel cells (9,523 gallons) installed in the center wing section. While the C-17s were designed and built to be used intensively, the ground crews were not. Most reservist support troops (especially mechanics) have been called to active service to avoid wearing out the active duty maintenance crews. Even so, six day work weeks, with 12 hour shifts, are common. One positive aspect of all this is that the flight and ground crews have gained enormous practical experience in carrying out such intensive operations.