Master Sgt. Dave Penisten of the 440th Air Expeditionary Advisory Squadron, verifies a compressor blade with 1st Lt. Ahmad Shah, Afghan air force maintainer at the AAF compound in Kabul, Afghanistan. Coalition advisers work daily at the AAF compound to instruct Afghan maintainers on the fine art of maintaining the Afghan Mi-17 and Mi-35 helicopters. Sergeant Penisten is stationed at Royal Air Force Mildenhall, England. (U.S. Air Force photo by Senior Airmen Amber Williams)