AFMC Command News

New tool assures aircraft material integrity, performance

  • Published
  • By Pete Meltzer, Jr.
  • AFRL Materials and Manufacturing Directorate
WRIGHT-PATTERSON AIR FORCE BASE, Ohio --  Air Force researchers working with industry have developed and effectively demonstrated a portable, nondestructive evaluation technology that measures in real time the electrical properties of specialty materials underneath the exterior coating of advanced military aircraft.

The new technology, referred to as the R-Card Characterization, or RCC, tool, is a handheld maintenance and support device that enables maintainers to verify the characteristics of specialty materials beneath the aircraft's protective topcoat, where they are not readily accessible for inspection. The tool helps ensure that the integrity and performance of these materials are within established technical order limits.

The Air Force Research Laboratory Materials and Manufacturing Directorate oversees the development effort. According to Juan Calzada, a project engineer in the directorate's Metals, Ceramics, and Nondestructive Evaluation Division, the RCC tool outperforms the technology currently used to inspect advanced aircraft materials and is a viable replacement for the existing technique.

"The small size and portability of the RCC tool allow easy deployment and use on the flight line, enabling real-time measurements in an operational support environment," Mr. Calzada said. "The new measurement device assures that maintenance actions and repairs have restored aircraft characteristics to within established limits."

Before the RCC tool was deployed, basic functionality was demonstrated by a previous AFRL research initiative. However, a fully functional, handheld system suitable for use by field-level maintainers in an operational environment had not yet been developed or demonstrated.

"Our goal was to develop a rugged, handheld device that could replace the antiquated, Special Test Equipment Mini Probe currently used by the Air Force to inspect these materials," Mr. Calzada explained.

The RCC nondestructive evaluation program had four objectives: to develop an RCC system performance specification; design the system; fabricate and deliver three prototype units; and evaluate system performance.

"System evaluation and demonstration, initiated in March 2006, indicated that the RCC system is comparable to the Special Test Equipment Mini Probe," Mr. Calzada said. "In short, a design effort was needed to mature the technology to a flight line-ready tool."

The RCC tool design addressed known deficiencies of the previous research and also leveraged opportunities to insert new technology. Beyond reliability and toughness, the design approach focused on ease of manufacture and featured easily replaced, disposable components. The program achieved all of these objectives, Calzada said

The RCC tool is composed of two major subsystems: the Processor Unit and the Probe Unit. The Probe Unit contains the radio frequency circuitry to generate the electric field and measure the signal properties from the electrical circuit created with the specialty material. The Probe Unit includes the electronics required to digitize analog signals.

The Processor Unit receives the measurements from the Probe Unit and determines the reflection coefficients. Once these are known, the resistance and reactance values can be calculated. The new tool is powered by three D-cell batteries and is completely self-contained and fully supportable in a flight line environment.