C-5 full crown skins being replaced Published Dec. 15, 2011 By Jenny Gordon 78th Air Base Wing Public Affairs ROBINS AIR FORCE BASE, Ga. -- Maintainers in the 559th Aircraft Maintenance Squadron are carrying out a unique mission at Robins. For the first time, 20 full crown skin replacements are being done on a C-5C. In the past, only a portion of each skin would be removed and replaced. Crown skins are the outer layers of an aircraft, held together by fasteners. There can be between 4,000 to 7,000 fasteners per skin, depending on its size. Due to the scope of the work, special scaffolds were built. "We've never changed multiple skins like this," Jeffrey Cranford, 559th AMXS aircraft supervisor, said. "When we would do a segment, we'd take about a 3-foot piece out, replace it and put a splice on it, but now we're changing the entire skin." It's taking between eight to 10 days for each skin to be replaced, but it's not the only maintenance being done. Flap tracks are being changed and repairs to aileron hinges are also being done. In addition to the C-5C's regularly scheduled depot maintenance, the crown skin package has added 26,000 man hours. Twenty eight day and swing-shift maintainers working 10-hour shifts are performing the work. It takes about a day and a half to remove fasteners, and several days to pull the skin down, drill holes, and complete installation. Wilbur Mathews, 559th AMXS work leader, gave kudos to his hard-working team. "The crew makes this happen," Mathews said. "No matter what you asked them to do, these mechanics did it with no issues or problems," he said. "And Senior mechanics have stepped up to lead apprentices." Ninety-five percent of the work has been completed to date.