Longerons help sustain safety of F-15s Published March 4, 2016 By Jenny Gordon Robins Public Affairs ROBINS AIR FORCE BASE, Ga. -- Without canopy sill longerons the F-15, one of the Air Force's most dependable fighter aircraft, can't safely fly and fight. These heavy duty strips of material are essential structural components by which the aircraft's skin is fastened. It holds the front third of the aircraft together and is the support structure that runs the length and side of the aircraft. It's also the structural piece where the canopy - the protective cover that encloses a pilot's body while in flight - rests before opening and closing. Following last fiscal year's recovery in the 561st Aircraft Maintenance Squadron, fiscal 2016 began with a new workload through the addition of canopy sill longeron replacements. The final F-15 rewire aircraft is currently in programmed depot maintenance. With that workload ending this fiscal year, many mechanics have already begun working on longeron replacements. Still in its early stages, a team of seven aircraft and sheet metal mechanics have already replaced longerons on two F-15Es. "It's important at this point because we're still in validation and verification - the learning phase of the process," said Wilnis Louis, 561st AMXS deputy flight chief. Driving the replacements include an area of the longeron, each measuring over 13 feet, that are subject to cracks in high stress areas due to the aircraft's high speeds and G forces. A total of six aircraft are planned for longeron replacements this fiscal year, which are being worked in conjunction with regular PDM. Craig Wright, 561st AMXS sheet metal mechanic, who has worked in F-15s for six years, was part of the team that worked on the first two aircraft. "We improved the process on the second one," said Wright. Mechanics must diligently tear down the cockpit area, removing such things as electrical boxes and duct work, the model's two seats, insulation blankets and the bulkhead longeron. "This is a very critical part where the canopy itself closes, sits on the longeron and is pressurized," he said. "It's very important - helping to keep the F-15 flying longer and last longer." Removing one longeron at a time on the first aircraft took eight days, for a total of 77 flow days. That aircraft sold last week. "This workload will continue to keep us busy as well as make the planes more efficient, while helping us get these back to the warfighter soon," said James Maddox, 561st AMXS structural work leader.