Invisible to the naked eye: NDI cracks down on the unseen

  • Published
  • By Senior Airman Marcus Morris
  • 8th Fighter Wing Public Affairs
KUNSAN AIR BASE, Republic of Korea --  Over time, aircraft parts wear out and break due to use. Some of the breaks and cracks are invisible to the naked eye and can lead to catastrophic problems if not found.

This is where nondestructive inspection comes into play. NDI is responsible for using nondestructive techniques to examine for cracks in the aircraft and to check the oil for contaminants and wear metals.

"The best part about my job is that we are able to find defects not visible to others," said Staff Sgt. Morgan Quinn, 8th Maintenance Squadron NDI assistance section chief. "It feels good to know that with our inspection methods we are potentially saving lives and aircraft."

NDI has five different portable crack detection methods for on- and off-aircraft inspections. The methods are penetrant, magnetic particle, eddy current, ultrasonic and radiography. Depending on what sections of the aircraft need to be inspected determines the testing method.

Along with the crack detection techniques, NDI uses a spectrometer to detect wear metals or contaminants in oil samples from the engines and the oil carts that refill the aircraft.

"Specific elements in a test can show what part is failing which is very important since it is a single-engine jet," said Master Sgt. Christopher Baldwin, 8th MXS fabrication flight chief.

Despite the name, wear metals are not just metals - silicon also falls into this category. Not all of the particles found are caused by wear -- some originate outside the machinery and others are additives. These checks are done every 10 flight hours to maintain the integrity of the aircraft.

"The jets wouldn't be able to fly without NDI's oil monitoring program," said Baldwin.

The magnetic chip detector from the aircraft's engine also allows NDI to detect wear metals and determine which part is wearing down. This is done after every flight with a scanning electron microscopy and energy dispersive X-ray analysis machine which checks carbon residue on the magnet to tell them where in the engine there is wear.

NDI works 24-hour operations five to six days a week to maintain the quality of the aircraft and its parts. They work hand in hand with crew chiefs, metals technicians and sheet metal fabricators to keep the F-16 Fighting Falcon flying and taking the fight north.