Structural maintainers provide backbone of RPAs
By Senior Airman Christian Clausen, 432nd Wing/432nd Air Expeditionary Wing Public Affairs
/ Published February 22, 2016
CREECH AIR FORCE BASE, Nev. (AFNS) -- When people have a blemish, they see a dermatologist; when they have a physiological problem, they see an orthopedist. For the MQ-1 Predator and MQ-9 Reaper, aircraft structural maintainers fill both the aesthetic and structural maintenance roles to keep remotely piloted aircraft in check.
Aircraft structural maintenance is part of the fabrication flight at Creech Air Force Base. The flight consists of the nondestructive inspection shop and the metals technology shop, which work together to ensure the life of the RPA enterprise is sustained with aircraft fully capable of mission execution.
"Depending on the base, aircraft structural maintenance is responsible for repair and fabrication of aircraft skin, structures, metallic tube assemblies, windows, canopies and corrosion control," said Tech. Sgt. Daniel, a 432nd Maintenance Squadron aircraft structural maintenance craftsman. "Here we focus on performing advanced composite repairs."
RPAs are mostly constructed of advanced composites materials which are as strong or stronger than metal but are superior in areas such as weight and stealth. These factors help give RPAs their 18-24 hour endurance time, high flight ceiling and the ability to stay off of some radar detection. Materials included in these composite groups used in RPA construction are carbon fiber, Kevlar and specialized versions of fiberglass.
"The RPAs are unique in that they're made completely of composite material," Daniel said. "In my opinion, this is the future of aviation because composites are stronger, cheaper, more durable, and they don't corrode. Like everything, they aren't invincible so we fabricate and repair the skin and structure for the aircraft."
If damage to the aircraft is suspected during an inspection, the structural maintainers will determine the type of damage, the severity and whether or not it's repairable.
"Typically with the composite material we commonly experience surface defects most followed by delamination and disbonds," Daniel said. "The number one enemy of composite is damage by water intrusion. The water vapor gets into a panel and then freezes at altitude, expands, and causes the panels to break."
To construct an aircraft out of composite material, carbon is generated into thread and then woven together to make a cloth-like material or laminate. The cloth is then covered in a resin and then shaped into panels before being subjected to extreme heat and pressure to form a solid panel.
Some common issues are disbonds, a separation of the laminate from the core and delamination, a separation of multiple plies of laminate. To fix these problems the structural maintainers use tools to sand panels down to the base of the panel and then replace the layers that were sanded away.
"If we didn't exist there wouldn't be a means of organizational level or even field level repair," Daniel said. "If an MQ-1 or MQ-9 had a structural flaw caused by wear and tear, moisture absorption or any way of structurally damaging the aircraft, it would eventually, dependent on the damage, become structurally unsound and not airworthy."
Aircraft structural maintenance is extremely important because an aircraft that can't fly is not only a loss of money for the Air Force, but in the RPA enterprise, reduces the situational awareness available to the joint commanders.
"The job can be very tedious because everything we do is very precise and has to be perfect the first time," said Senior Airman Brian, a 432nd MXS aircraft structural maintenance journeyman. "There's a lot on your shoulders because if you mess up, that plane is down for another 24 hours and you have to answer a lot of questions. It's a very important job because if we mess up, a plane could crash."
During the repair process, even if one layer of carbon fiber, Kevlar or fiberglass is improperly bonded, it could result in a mistake that still renders the aircraft unable to fly, making the shop start the process over from scratch.
Although the job may be tedious, Creech structural maintenance takes it seriously, ensuring everything is ready to go. They consistently produce an excellent quality assurance inspection pass rate of 95 percent. The average Air Force QA inspection rate is 80 percent.
(Editor’s note: Last names were removed due to security and operational concerns.)