(Left to right) Airman Mark Vadnais and Airman 1st Class Christian Mains, 28th Aircraft Maintenance Squadron able chiefs, study a B-1B Lancer technical order at Ellsworth Air Force Base, S.D., Jan. 21. B-1 crew chief Airmen must attend 22 academic days, consisting of 108 hours of training, before becoming a true crew chief. (U.S. Air Force photo/Senior Airman Anthony Sanchelli)