Structural Repair Design is a process that starts from the conceptual design phase until the retirement of an air vehicle, it provides a price competition advantage, and influences the air vehicle’s safety and airworthiness. With the development of material technology and the advanced use of composite materials in the aviation industry, there have been changes in the repair design methods which play a crucial role in the competition among companies.
The aviation industry grows day by day while the materials used increase in diversity along with it. The increasing importance of aviation, advances in technology, and the desire to reduce cost make significant contributions to the development of the industry.
Although we are more interested in the features of the aircraft, we’re also surprised by the materials used in their production.
The Use of “Cloth” in Repair Services
Currently, “cloth” is used to make repairs in the air vehicle’s fuselage or wings. The damage caused by birds, hard landing, or an impact of any kind is repaired by “cloth” which is an advanced composite material reinforced by carbon or glass fibers.
As in other design processes, the structural repair design requires this material to fulfill all qualifications, to be tested for endurance values, and to be verified in terms of the load scenarios the air vehicle can meet with resistance calculations. Global aviation authorities like the European Aviation Safety Agency (EASA) and the Federal Aviation Administration (FAA) or local authorities like the Directorate General of Civil Aviation (DGCA) audit the companies' repair design processes and nonconformity cycles for the Company Design Organization Approval (DOA) release or Type Certificate (TC) release of the product. “Step sanding wet layup repair” is a repair method that meets the certification requirements.
The Importance of Repairable Design and Air Vehicles
Repairability is one of the dozens of main criteria in the design of an indigenous air vehicle. “Easy, fast, and low-cost repairability” along with other design criteria such as low fuel consumption, high payload capacity, and durability provide advantage in the sale of air vehicles and the competition among aviation companies.
With the replacement of thermosets by thermoplastics and the additive manufacturing method in the aviation industry, new methods of repair design will add new chapters to structural repair manuals. Companies that follow and pioneer these technologies will be on the front line of the industry.
At Turkish Aerospace, repair design operations are carried out by the Department of MRB Engineering of the Deputy Directorate General of Central Engineering. The Department of MRB Engineering has the only team of engineers with a delegation with signature authorization from Boeing, Airbus, Northrop Grumman, and Bombardier.
Story: Faruk Oğuz - Chief Engineer of MRB Engineering