Aerospace Composite Repair
Major airplane and helicopter manufacturers increasingly rely on composite materials for primary structural applications. Even more, industry experts expect the use of composites to increase in the future. In particular, helicopter manufacturers often turn to composites using Kevlar, fiberglass, and carbon fibers to improve strength and decrease weight.
Repairing, inspecting, and testing these new materials requires different processes, materials, and skills than traditional sheet metal. At the same time, the specialized skills needed to repair composite components remain in high demand. This growing need explains why many commercial and military aviation organizations rely on a trusted, experienced, and certified partner, like Overhaul Support Services (OSS), for composite repair and other services.
The TIGHITCO OSS Composite Repair Process
Step 1: Disassemble, Clean, and Inspect
Our state-of-the-art facility can disassemble, clean, and inspect composite parts. While detecting damage to sheet metal relies on a relatively straightforward visual inspection and repair, diagnosing composite damage often requires a more rigorous approach and different techniques than simply visually inspecting the surface.
A quick visual inspection can reveal internal damage; however, it takes the right equipment and training to detect significant problems below the surface. For instance, a surface crack might appear trivial. Still, a trained technician needs to determine if the damaged area has led to serious water damage, which requires structural repairs to ensure the proper balance and integrity of the aircraft.
In addition, every original equipment manufacturer (OEM) will offer distinct guidelines for the material, part, and brand. Most OEMs provide relatively consistent inspection instructions, including a visual inspection and a deeper inspection of suspected or known damaged areas. Examples of inspection procedures could include non-destructive inspection (NDE), paint removal, tap testing, and ultrasound. A qualified MRO facility, like OSS, will keep up with specs from various manufacturers.
Step 2: Composite Repair and Overhaul
Composite aircraft parts may suffer from various types of wounds, which may require repairs that range from simple to complex. In turn, the type of repairs needed will depend upon the type and severity of the damage.
Types of Damage to Aircraft Composites
The repair process will depend upon the severity and kind of problem and which components the damage affects. Examples of types of composite damage in aircraft that OSS can diagnose and repair include:
- Abrasions and punctures: Typically, visual inspections will reveal minor scratches, dents, or shallow indentations that are relatively quick and easy to repair. Still, aviators should repair even minor damage promptly to keep it from letting in moisture or spreading.
- Disbonding and delamination: Sometimes, this more severe kind of impact damage evades casual inspections. The skin can separate from the core, reducing the part’s integrity. This kind of damage also makes the core more susceptible to water or UV damage. Permanent solutions for this type of damage will take more effort than repairing superficial abrasions.
- Water damage Water can seep under the surface because of seemingly small cracks or dents. In time, the water weighs down the structure. Expanding ice can seriously hurt the component’s structural integrity if it freezes. Technicians must take extra care to completely dry the component before the curing step, as steam can build up enough pressure to blow off the skin.
- Fuel damage: Some composites cannot recover from contamination by fuel, oil, or hydraulic fluid. Since the technicians can’t clean or dry them, they must remove and replace the contaminated materials.
Before designing the appropriate repair, the technicians will gather information about the component, like its composite fibers, resin, and core materials. Typically, they will also need to sand the part to remove the paint.
Composite Repair Types
Types of repairs generally fall under these four general categories:
- Nonstructural repairs: Mostly cosmetic, these repairs may require adding filler materials, sanding, and repainting.
- Semistructural repairs: These repairs address more than just cosmetic damage. Still, repairing the damage only requires removing damaged core materials, rebuilding with laminates, sanding, and refinishing.
- Resin injection repairs: The technician injects resin into a damaged component as a quick and typically temporary repair for delamination. This type of repair may not offer a long-term solution.
- Structural repairs: Extensive repairs to primary structural parts will require more extensive processes, including the scarf or step method. These methods can restore the damaged part to its initial bonding, strength, and stiffness requirements.
Step 3: Assemble and Test
Finally, our team must reassemble the components and reinspect or test the parts. Each OEM will provide specific criteria, possibly including inspections for proper curing, complete bonding between the structure and repair, and any porosity or voids in the repair.
Find a Trusted Aircraft Composite Repair Partner
Today, composite materials make up a sizable portion of modern aircraft structures. Manufacturers primarily favor composites for their favorable strength-to-weight ratios and other beneficial characteristics. At the same time, various aircraft types and models use many different types of composites, with new materials introduced constantly. The proper approach to composite repair will depend upon the material, component, and damage. Thus, relying on trained, experienced, certified, and up-to-date aircraft repair facilities is essential.
At OSS, military and commercial aerospace customers trust our highly trained and certified staff and facility for reliable, secure repairs. We boast a workforce with an average of 10 years on the job and operate in an EASA- and FAA-certificated repair facility. Find out more about our aircraft repair services, and contact us today to tell us about your aircraft.