Each aircraft undergoing planned or scheduled depot-level maintenance is clean, painted, and free of corrosion once its sustainment cycle has been completed.
The 558th Aircraft Maintenance Support Squadron’s corrosion control team, part of the Warner Robins air logistics complex at Robins Air Force Base, Georgia, USA, does its best to ensure each aircraft has a showroom finish.
Todd Lavender, process engineer and corrosion control process manager, says the team’s mission is to make sure that aircraft are de-painted correctly, using proper materials, and then repainted properly.
“The de-paint portion of the aircraft is mainly to prepare the aircraft for overhaul, as well as reduce the amount of paint on the surface,” he says. “Also, it provides a better means to inspect the aircraft, perform non-destructive inspections, and helps them to identify any corrosion areas, as well.”
Lavender says once the aircraft has gone through most of its P/SDLM cycle, it returns to start the paint process.
“They’ll mask the aircraft, wash the aircraft, and apply surface pretreatment to promote adhesion for the primer that we apply,” he says. “Then they will apply the primer. In some areas, they will apply polysulfides sealant, which is mainly used in the high corrosion areas—such as the surfaces that take all the direct wind forces during flight, like the leading edges of the wing. Then they apply the topcoat of paint.”
In the early years of the Air Force, Lavender explained that aircraft coming into Robins for sustainment were polished aluminum, as opposed to being painted.
“I think from a corrosion control standpoint, the paint and primer that we apply is specifically made for protecting aircraft from corrosion,” he says. “It protects the aircraft from the hazards of flight and the harshness of weather during flight. Also, it protects from the different conditions an aircraft might land in, like blowing sand from the desert, winter snow and ice, or salt from ocean spray you get on the coast.”
Lavender notes that the paint gate time depends on the size of aircraft.
“For the large cargo aircraft like the C-5 and the C-17, it typically takes about 24 workers per shift,” he says. “The whole process from induction into that paint gate usually takes seven to 10 days, with the C-5 Super Galaxy aircraft on the tail end of that time frame.”
Lavender believes the current way of mixing paint is time consuming.
“Currently we mix the paint using one-gallon (3.8 L) kits, which is a base can and a catalyst can, and they are mixed together, times 200 for C-5 aircraft,” he says. “Each can is mixed individually and dumped into our paint carts, which is a large pot that feeds all the paint guns. What we are installing in two of our buildings now—and then later in our other two buildings—is a plural mixing system that will mix the paint on demand to provide a consistent mix. This will be faster than our old method of manually mixing the one-gallon kits.”
“So, instead of coming in one-gallon can kits, we will have 200-gallon (757.1 L) kits in drums that will be pumped into the tanks for the plural mixing system… and then they’ll be dispensed out of those tanks and mixed up to the proper ratio,” he adds.
With less interaction with the paint, Lavender believes it will be safer, quicker, and a more efficient way of painting.
“There are things in the paint people don't really need to be around while it’s being mixed,” he says. “There will be less paint cans going into the hazardous waste barrels and a reduced cost in disposal of material. It will be a more efficient way of mixing the paint for the aircraft. Instead of having different individual mixes by different people, you’ll have a consistent mix meaning one paint consistency for the entire aircraft.”
Lavender says their goal is to send an aircraft back to the customer without any defects.
“They expect their aircraft to have a showroom-quality paint finish,” he says. “To me personally, there's a satisfaction for me knowing there are steps in the process that I've helped to lay out. By using those steps that I helped develop, we're sending a good aircraft back to the customer that should perform like they need it to perform.”
Source: Robins Air Force Base, www.robins.af.mil.