RAF MILDENHALL, England -- The KC-135 Stratotanker first flew for the U.S. Air Force in August 1956, and it continues to be a vital part of the Air Force’s arsenal to this day.
Although the 15 KC-135s of the 100th Air Refueling Wing have seen plenty of years, the teamwork of several different shops within the 100th Maintenance Squadron and Aircraft Maintenance Squadron will keep flying them for years to come.
One method of keeping the KC-135 operational is an isochronal inspection, or ISO inspection.
“The ISO inspection is the most in-depth maintenance and inspection done at home station,” said Staff Sgt. Jason Hansen, 100th MXS periodic dock controller. “It is conducted every 24 months, 1,800 hours of flight or 1,100 landings.”
Since the ISO is a comprehensive inspection, it takes multiple phases and multiple Air Force specialties to complete the two to three-week inspection.
“There are multiple phases during the ISO, including the de-panel and inspection phase, fix phase and back lines phase, which is essentially an operations check of everything that was fixed,” explained 1st Lt. Nathan Zimprich, 100th MXS maintenance flight officer in charge.
The various shops involved in the ISO work hand-in-hand during the critical inspection, with Airmen from eight different specialties involved.
“We have work-cards specifically for the engines, which is a detailed list of what needs to be inspected during the ISO,” said Staff Sgt. Andrew Plemmons, 100th MXS aerospace propulsion craftsman. “One of the many things we check are magnetic-chip detectors, which grab metals out of the oil and give us a good indication of the health of that engine.”
After de-paneling, the Non-Destructive Inspection team conducts inspections, like the ultrasonic process, said Staff Sgt. Ryan Dowtin, 100th MXS NDI technician. The ultrasonic process checks for a difference in thickness, indicating a weakness or defective layer below the surface. This could be caused by icing, wear and tear, or fuel deterioration, he explained.
Airmen from hydraulics and corrosion control also work on the aircraft while NDI completes their inspections.
“During the ISO, we remove the boom from the aircraft and get parts thoroughly checked by NDI,” said Senior Airman Dakota David, 100th MXS hydraulic systems journeyman. “NDI will inspect for cracks and while the boom is off, corrosion will strip the paint from the other side of it - the side that attaches to the aircraft - so NDI can come inspect the forward fitting pivot for cracks.”
In order to coordinate all of the work between the different shops, it’s essential to have a dock controller overseeing the entire inspection.
“Our job as the dock controller is coordinating steps A through Z -- overall there is a goal and our mission is to ensure that the aircraft is ready to go,” Hansen said. “We manage all the shops and coordinate for each of the jobs through meetings, constant communication and good solid turnover.”
Although the dock controller facilitates the communication between the different shops, it’s the cooperation of each shop that is the reason these aircraft are still flying to this day.
“I’m a big advocate for the team effort, and I love being a part of this process,”Zimprich said. “One team, one fight. We all come together, we know what our mission is, we have a job to do, and we set out to do it and we do it excellently every time.”