By DAVID WESTLUND
The corporate climate is highly competitive, the competition fierce; best your competitors or be bested. Narrow margins between profit and loss, urgent deadlines to meet, and logistics are all challenges that corporations face. Perhaps nowhere is this truer than in the airline industry. There is one venue, however, where the airlines put aside their competitiveness in the name of safety: The Airlines 4 America (A4A) Nondestructive Testing (NDT) Forum.
The A4A NDT Forum enables NDT professionals and industry leaders to meet each year and discuss current trends, issues and successes in NDT methodologies. The Forum draws participants from various disciplines, including equipment designers, technicians, vendors, regulatory authorities, Original Equipment Manufacturers (OEMs), Maintenance and Repair Organizations (MROs) and airline personnel. The Forum exhibit hall features displays, including the latest NDT and related equipment, processes and services.
NDT plays a huge role in the safety of commercial and general aviation. Throughout an aircraft’s life, there is the potential for damage from numerous sources including: bird strike, hail, runway debris, lightning, ground service equipment (GSE), incursions with other aircraft, and fatigue damage from repetitive loads from normal operation. The role of the inspector is first to determine if there is damage from an event and, if there is damage, to determine the severity of the damage by sizing it. This information can then be used by structural analysis engineers, who use tools like Finite Element Modelling (FEM), to determine the residual strength of the structure. The extent of the damage will determine whether the part needs to be repaired or replaced. NDT even plays a role in making sure the repair is done properly. Regardless of the decision that is made of whether to repair or replace or to bolt or to bond, the airplane must still meet the Federal Aviation Regulations (FARs) in order to be considered airworthy. For example, in the United States, Title 14 (Aeronautics and Space) CFR Part 25 (Airworthiness Standards, Transport Category Airplanes) Subpart C (Structure) contains the regulations that set forth the standard for an aircraft’s ability to withstand the loads (forces) that it will experience in flight.
There are many tools that an inspector has available to them to inspect damage on an aircraft. Each tool has a unique purpose and there is really no tool that can do it all. The most basic of all inspections is the visual inspection. This can be as simple as a walk around the aircraft, looking for signs of damage. The shortcoming of this method is that some spots on the aircraft can be difficult to see from a walk around and the human eye isn’t always going to catch everything. In some cases, such as on a composite structure, there is no external indication of damage even though there may be hidden damage beneath the surface of the aircraft.