Engine Forensics

Failure Analysis Service Technology (FAST) FOD kit

The base FOD Monitor, SSgt. George McMillen, took samples of the damage using the newly acquired FAST (Failure Analysis Service Technology Inc.) FOD kit and sent them out for analysis. The kit takes a nondestructive sample using sticky tape and acetone which is then analyzed using a scanning electron microscope. The makers of the FAST FOD kit then read the atomic makeup of the residual debris on the sample and determine the composition of the culprit. Safety wire has a different chemical signature from an aircraft grade bolt, and when items impact the engine they leave behind their unique chemical fingerprints.

As was noted earlier, forensics is the scientific analysis of physical evidence and this process is really comparable to lifting a fingerprint. In this case, the results came back stating that concrete had caused the damage. The signature not only included concrete, but it also showed paint with a slightly metallic characteristic.

Shortly thereafter the crew chiefs started noticing paint chips lodged in the aircraft tires and subsequent examination of the runway revealed heavy flaking of the paint used for the runway numbers and stripes. The paint had multiple coats over years of repaints and the concrete was breaking loose underneath. Recent repairs to the primary had dictated the use of this alternate runway which was not commonly used for fighter operations. The dents on the strake and ventral fin had also been caused by the paint/concrete being thrown against the airframe from the aircraft tires on landing. The problem was quickly solved by the 122nd and the local airport authority by having all the old paint removed and new reapplied.

CMSgt. John Maxson, chief of quality assurance, says, “The main runway was out of service for several weeks which caused us even greater concern because we were afraid we were using a runway with multiple problems. Bottom line: the FAST FOD kit clued us into a problem that may not have been resolved without the results provided by the manufacturer.”

In another nonrelated incident, an aircraft returned from flight with damage to the wing fuel tanks, one of which had a large hole in the nose of the tank. The pilot reported flying into heavy precipitation and FAST FOD analysis results showed no foreign fingerprint and the consensus was that the damage had been caused by hail. Even in this case there was an advantage to using FAST FOD because it helped determine that no further action was required.

Many other uses of the kit can be envisioned, such as determining damage to airframes from ground equipment, and even nonaircraft related incidents. Undoubtedly the use of the kits will continue to grow as aircraft maintenance personnel become more aware of their usefulness. Other branches of the U.S. military are implementing the use of the FAST FOD kit to help them improve FOD programs and help with investigations. There are many other success stories and there will, in all probability, be more as the kits see wider implementation. In this case it helps the 122nd to continue to be ready to meet any threats posed to the United States and its allies and to safeguard the aircrew flying the jets.

And of particular interest to us all — it saves the taxpayers money.

David Chamberlin has an A&P and a degree in aviation management. He is currently a senior customer service rep at Rolls-Royce and a quality assurance inspector with the Indiana Air National Guard.

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