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Behind the KC-135 periodic inspection

  • Published
  • By Airman 1st Class Mackenzie Richardson
  • 92nd Air Refueling Wing Public Affairs
The hangar smells of oil while the sound of Kenny Loggin's "Danger Zone" echoes through the rafters of the hangar. The KC-135 Stratotanker is torn apart, panels removed, screws extracted and the pilot's chair is sitting on a table. The 92nd and 141st Maintenance Squadrons are in the "look phase" of the last periodic inspection of the year. PEs are one of the most thorough and time-consuming inspections conducted on an aircraft. It is conducted every 24 months, 1,800 flight hours or 1,000 landings. On average, the 92nd and 141st MXSs conduct 12 PEs a year.

Day shift and swing shift are comprised of roughly 35 Airmen who can be found looking over every nook, cranny, fastener and wire on the jet. During mid-shift, about five Airmen work on the tanker. PEs involve approximately 16 different Air Force Specialty Codes. Nondestructive inspection Airmen are found working along hydraulics and fuels Airmen. The 92nd Aircraft Maintenance Squadron offers their crew chiefs and avionics Airmen for assistance.

"Working with various AFSCs helps everyone become a well-rounded maintainer," said Senior Airman Frederick Chung, 92nd MXS periodic inspection crew chief. "Everybody gets a little knowledge about every system."

All the maintainers who work on a PE jet are held to high standards of performance. With millions of dollars of technology, equipment and people's lives on the line, ensuring the highest quality aircraft is sent back to the fleet is the goal for every PE. The inspection ensures all problems on a jet are identified and repaired. These problems can span anywhere from worn padding on the arm of the co-pilot's chair to a hydraulic fluid leak in the wing.

The periodic inspection begins with a "pre-dock." Pre-dock is a meeting between maintenance shop representatives where an agreement is made on what work will be conducted throughout the 13-day inspection. This allows flight line Airmen to locate initial discrepancies and log them for the PE team. PE Airmen take ownership of the discrepancies and the jet when it rolls into the hangar for the start of the inspection. Periodic inspections are a buying and selling process in which the 92nd and 141st MXSs purchase the jet from 92nd AMXS to begin the initial phase of the inspection. This phase is known as the "look phase," and lasts for five days.

During the look phase, all the discovered discrepancies are logged both in paper form and in a computer system.  Parts needed for the jet are ordered during this time and become available for install during the "fix phase." The 92nd MXS works closely with the 92nd Logistics Readiness Squadron during this process to ensure the proper parts are ordered and arrive in a timely manner.

"The most important part of a periodic inspection is the diligence and thoroughness of your work," added Chung. "Because we are conducting a much more in depth inspection; we have to have sharp eyes to catch every small defect in order to prevent any further mishaps down the line."

The 92nd MXS recently proposed a plan for a longer periodic inspection based on data collected by the squadron since September 2013. The new proposal for PEs was approved by 92nd and 141st Maintenance Group command, changing the 10-day process to a total of 13 days. Higher rates of use, the increase of aircraft age and the decline of parts available for the KC-135 has led to a significant increase in discrepancies found during the "look phase." Over the last 24 months, the average amount of discrepancies found during a PE increased by approximately 129 percent. In addition to the increase of discrepancies, within the last 12 months the PE team has lost a combined total of 138 years of active duty and guard KC-135 experience. The average Airman has approximately three years of experience.

"A 13-day periodic inspection gives Airmen more time to train, slow down and take a better look at things," said Tech. Sgt. Jeremy Martinez, 92nd MXS periodic inspection section NCO in-charge and PE dock controller. "A big aspect was giving more time for training to our younger Airmen."

At the end of the look phase, quality assurance representatives visit the site of the PE to validate the inspection process and ensure it was a success. QA is a hand-picked team who serve as the primary technical advisory agency in the maintenance organization, assisting maintenance supervision at all levels to resolve quality problems. The evaluation and analysis of deficiencies and problem areas are key functions of QA that highlight and identify underlying causes of poor quality in the maintenance production effort. During a PE, QA averages 15 to 30 evaluations, checking four areas for safety and security violations.

After the initial phase of PE is complete, the second phase begins. This phase is known as the "fix phase."  Airmen have a total of eight days to repair, fix and replace various parts on the jet.

The fix phase challenges Airmen to use their maintenance knowledge and their technical orders to complete repairs, replacements and the installation of various parts. Technical orders are instruction manuals on how to complete any task in maintenance. These manuals help ensure the safety of pilots, crews and millions of dollars in equipment. On average, a PE jet has 1,200 maintenance actions to include installations, evaluations, or discrepancies to be refurbished or repaired.

The PE jet must fly locally before it's able to participate in missions, deploy or go on a temporary duty assignment. After the fix phase, the condition of the jet must be determined safe-to-fly. Aerospace propulsion Airmen assist in testing the performance of the engines. To ensure the safe-to-fly status, engines are ran anywhere from idle to full power over an eight to 16-hour time frame. Running these engines ensures certain operational checks are completed.

When the testing is complete, the jet is moved from PE to fuel cell. Aircraft fuel systems specialists work inside and outside the fuel tanks to repair, inspect and install aircraft fuel system components, preparing the jet for its first flight.

After fuel cell has completed their repairs, panels are put back on the jet and sealed. The jet has officially entered "post-dock." This wraps up the periodic inspection, the jet is sold back to the flight line and is returned to the 92nd AMXS for a "pre-flight" inspection prior to the first flight. Even after the 92nd AMXS resumes possession of the aircraft, the 92nd and 141st MXSs continue to show maintenance pride by performing the pre-flight inspection and launching the aircraft for its first flight.

"A PE affects the health of the fleet," added Martinez. "The aircraft is getting older and we identify a lot of issues that could be potentially catastrophic if we didn't repair them now. Without periodic inspections, we wouldn't be able to support the mission properly."