Managing Efficient Aircraft Maintenance with the Right NDT Inspection Technology

Aviation is impressively complex—and incredibly high-stakes. That’s why governments across the world mandate detailed inspections of aircraft at regular intervals. All companies operating aircraft must have the means to maintain them, whether in-house or on contract. Some aspects of aircraft inspections, like cleaning the instrument panel, can be performed by hand, eye, and a little elbow grease. Others, like mapping corrosion and metal fatigue in the fuselage longerons, wings, and turbines, can only be accomplished with special instruments. To comply with regulations and maintain flight safety, companies must invest in nondestructive inspection technology for aircraft maintenance. In order to maximize value, companies performing inspections should seek out the nondestructive testing (NDT) equipment that allows their employees to work as efficiently as possible.

Aircraft Maintenance and Inspection Regulations

There’s no ambiguity involved. United States Federal Aviation Administration regulations insist that an aircraft is not allowed to be operated unless it has undergone an annual inspection or airworthiness certificate inspection within the last 12 months.Foreign governments make similar inspection demands. For U.S. aircraft, the requirements of these inspections are detailed in the federal code. In short, aircraft components are separated into several groups, including fuselage and hull, cabin and cockpit, all internal systems (electrical, mechanical, etc.), engine and nacelle, engine fan blades, internal engine components, landing gear, wing and center section, empennage, propeller, radio, and everything else not included in one of the other groups. Each component in every group must be inspected, and the inspection must be documented. Thorough inspections of large commercial aircraft can take thousands of man-hours and weeks of aircraft downtime. Special equipment is required to accurately inspect these components without damaging them. The more efficient and powerful the inspection technology used, the less time it takes to complete inspections and give these aircraft the all-clear for a safe flight.

The Most Effective Nondestructive Analysis Technologies Used for Aircraft Inspections

When you’re inspecting aircraft, you can’t just kick the tires and call it good. Often, corrosion, density, thickness, or conductivity variations, honeycombing, and even cracks in metallic, composite, or multilayer materials are invisible to the naked eye. It’s likewise extremely difficult to detect cracks and voids in welds, beads, joints, bolt holes, and rivet boundaries. To clearly see such damage or defects, you need to be able to look inside the material. You won’t be able to do this with the naked eye without cutting the material open. That’s where nondestructive testing comes in. Two of the most effective nondestructive imaging technologies that give aircraft inspectors insight into their work include ultrasonic testing and eddy current testing.

• Ultrasonic testing uses echoes from high-pitched sound waves to identify and evaluate anomalies. Ultrasonic testing is best used to measure the thickness of materials and to detect deep subsurface anomalies, making it an ideal technology for inspecting turbines and other thick components. Advanced phased-array ultrasonic testing (PAUT) is the preferred NDT inspection method of composite materials including carbon fiber reinforced polymers (CFRP).
• Eddy current technology detects abnormalities near the surface of conductive materials by analyzing the “eddies” created when the material interacts with a magnetic field. Eddy Current technology is capable of detecting surface and sub-surface defects including cracks, corrosion, and heat damage in conductive materials with a high degree of precision while at the same time producing a digital record of the results. In aviation, Eddy Current testing is used to inspect skins, stringers, frames, rivet holes, tubing, and many other ferrous and non-ferrous components. Multi-coil arrays take eddy current technology many steps further. Technicians can capture more information in a single pass and dramatically increase the speed, accuracy, and repeatability of nondestructive tests, especially on large inspection areas like fuselage skin panels. Multi-coil arrays transform the eddy current inspection from a process that might last several minutes per joint to one that takes seconds.

All inspection techniques can be time-intensive, and technicians must be properly trained and equipped in order to achieve meaningful results. At the same time, high-volume MROs must meet demanding inspection schedules. In order to negotiate these conflicting demands, maintenance managers must equip their workers with fast, powerful instruments, which can reliably find flaws without delaying work. Instruments with simple, intuitive software are preferred, to cut down on training time and operator errors. Portability, ergonomics, and battery life are vital to flight line technicians. In addition, the more easily that software can export data for compliance documentation, the better. To maximize value, inspection equipment should be durable and able to stand up to dirt, dust, and vibration. Inspecting aircraft properly keeps passengers and crew safe, and keeps companies in compliance with federal regulations. Specialized ultrasonic and eddy current equipment is ideal for performing these inspections. In order to meet busy fleet inspection schedules, maintenance managers should seek out the fastest, most reliable, and easiest-to-use equipment available.

For over 50 years, Zetec has been a leader in the NDT industry. We’re proud to be a leading provider of nondestructive analysis instruments for aircraft inspections. For testing equipment that’s accurate, simple, dependable, and fast, contact us today.