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|NDT.net Issue - 2007-08 - NEWS ||NDT.net Issue: 2007-08|
Publication: e-Journal of Nondestructive Testing (NDT) ISSN 1435-4934 (NDT.net Journal)
Maintainers seek hidden flaws, help save livesUnited States Air Force, Washington, DC, USA
by Senior Airman Olufemi A. Owolabi 332nd Air Expeditionary Wing Public Affairs
When it comes finding and detecting flaws that can cause a potential failure to aircraft engines, NDI Airmen are relied on to use various analytical methods and technologically advanced equipment.
"What we're trying to do is to predict a failure before a pilot steps into the aircraft," said Tech. Sgt. Roy Giller, a non-destructive tester deployed from the Oklahoma Air National Guard's 138th Fighter Wing at the Tulsa International Airport. "If there's a failure and we can't catch it before it happens, that means a pilot could die."
When a crew chief finishes a pre- or post-flight inspection and finds a defect or crack in an aircraft, the NDI Airmen are called for additional inspections.
The NDI team here, consisting of ten Airmen, has five discipline areas used to inspect and detect cracks or pits in aircraft parts. They are radiography, ultrasound, magnetic particle, fluorescent penetrant and eddy current inspections.
"All these inspections are very important because each one is unique," Sergeant Giller said, "and each one has its own specific way of detecting various types of defects. If one is looking for surface defects on one part, the fluorescent penetrant is a good method to use, but if one needs to go deep and check aircraft parts, the ultrasonic soundwaves is a perfect method."
Radiography is used to examine the interior of a part and to look for defects like cracks, water entrapments and foreign object damages. Magnetic particle, ultrasonic soundwave and radiology are used when looking for surface and internal defects.
"The majority of NDI shops use eddy current," the sergeant said. "It is an all-around and good-to-use instrument when it comes to checking for cracks in aircraft."
Among these methods, the most commonly used here is the eddy current inspection for detecting cracks in aircraft parts.
"We do a lot of eddy current jobs, especially with the F-16 (Fighting Falcons)," said Senior Airman Brien Kwapisz, an NDI member deployed from the 35th Fighter Wing, Misawa Air Base, Japan. "Radiography checks internal parts to make sure they are in proper working condition. We do magnetic particle inspections on or off an aircraft."
Apart from checking parts on aircraft, NDI Airmen also analyze oil samples as part of the joint oil analysis program. They do trend analysis on oil samples taken from aircraft engines, and by doing this, they are looking for critical oil wear metals such as iron, aluminum, silver, titanium, chrome and nickel, among others.
A high rating of iron in an oil sample, for example, can indicate an abnormal engine wear in an aircraft engine.
"Nickel, iron, chromium and silver are big ones for us," Sergeant Giller said. "Aircraft bearing department is comprised of a lot of these materials."
The shop uses Spectroil M/N oil analysis and jet scan machines for this oil analysis procedure. Spectroil M/N checks for very minute wear metals and the jet scan checks bigger pieces of wear metals.
"Our biggest job in NDI, either in a war zone or home station, is the joint oil analysis program," Airman Kwapisz said. "The only time we don't do this here is when an aircraft doesn't fly, and it is rare for aircraft to not fly here."
NDI Airmen man their 24-hour shop doing oil analysis and inspections to ensure the flying mission goes on every day.
"Because we never know when an inspection on an aircraft might come due, and planes are flying around the clock, we have to do oil analysis on them daily," Sergeant Giller said. "The same thing with jet scan, we have to do it 24 hours, seven days a week."
Whether deployed or at a home-duty station, NDI Airmen do similar jobs but with a little difference in a deployed environment.
Airman Kwapisz described this difference as the expeditionary mindset each NDI Airman must have while in a combat zone.
"Our job is a lot more stressful in a combat zone because we can't keep planes down very long here," he said. "We always want to get that part taken care of in a timely manner. Just like a Blackhawk (helicopter) here, its unit needed it right away, and we had to jump on it very quickly and made sure it was working properly so that it could be used to fight the enemy and to support the Air Force, Marine and Army troops on the ground."
The Airman said deploying here has opened his eyes to so many different units and how the NDI shop can support these units.
As a result, he said NDI Airmen always should be willing to learn something new every time especially from other Airmen in the shop with lots of experiences.
Their job satisfaction comes when they go out and actually find a crack in an aircraft. They know this crack is going to be fixed by the sheet metal shop, metals technology or other maintenance units here before the crack develops into a catastrophic failure.
For Airman Kwapisz, apart from finding cracks and gaining new experiences, he feels a sense of pride, knowing how his job impacts the mission here and, in effect, how it saves many lives.
"A little crack can cause a bigger crack, and with this, maybe a wing can fall off an aircraft; we don't know what can happen," he said. "In our job, knowing that we help put jets in the air by preventing an accident before it happens is a big satisfaction for an NDI Airman. Also, knowing that we can prevent a pilot from being hurt by simply burning an oil sample is always a mission-accomplished day for me."
United States Air Force, Washington, DC, USA - Air Force Link http://www.af.mil