By Sgt. Daniel SchroederJuly 1, 2012
FORWARD OPERATING BASE WOLVERINE, Afghanistan -- In order to maintain operational readiness, the 25th Combat Aviation Brigade ensures that all its equipment is serviced within the proper guidelines to provide security for the Soldiers on the ground.
For Soldiers of Company D, 2nd Battalion, 25th Aviation Regiment, 25th CAB, the equipment they service are not computers or vehicles, but UH-60 Black Hawk and AH-64 Apache helicopters.
These services are called preventative maintenance inspections, or more commonly referred to as phase maintenance. During phase maintenance, the aircraft is systematically broken down into sections and each part is inspected for cleanliness and condition by the PMI manual.
"Our mission is to find any problems with the aircraft, repair them, and push out a bird (helicopter) as close to new conditions as possible," said Sgt. Phillip Dowdy, a UH-60 Black Hawk mechanic with D/2-25 AVN, 25th CAB. "There is something new to be learned each phase. Each individual inspection helps us to learn about each part."
When an aircraft is received for phase maintenance, a team of Soldiers begin the break down.
"We have 10 UH-60 crew chiefs and 10 mechanics from our support shop made up of avionics, sheet metal, power train and power plant technicians," Dowdy said. "We brought some new Soldiers with us, fresh from the school house. Each of us has gained a lot of experience from the nine PMIs completed since arriving here."
Phase maintenance is based off the amount of flight hours the aircraft has since the time it was built or after its last phase maintenance session. Two time periods are used for the PMIs conducted for UH-60s; the first is at 360 flight hours and usually lasts for seven days. The second is at 720 flight hours and lasts for roughly 14 days due to the extensive tear down and inspection. During the deployment rotation, the phase teams will continue to perform PMI 1 and 2 until it is the aircraft's time to be shipped back to the states. Once back in the states, the aircraft will undergo a reset where it will receive a complete overhaul.
During a PMI 1, panels are removed from the aircraft, a fuel integrity test is performed, basic inspections of the aircraft are conducted, it is washed, and a rig test is used to verify the measurement of the blade angle. When a PMI 2 is underway, both engines, oil cooler, drive shafts, and auxiliary power units are removed from the aircraft. Air is run through the fuel lines to help check for leaks. Also removed are the main rotor head and main mast seal.
"We note the deficiencies when we come across them in our inspections," said Chief Warrant Officer 4 William Rector, the Production Control Officer-In-Charge for D/2-25 AVN, 25th CAB, originally from Austin, Texas. "Of those deficiencies, we remove, repair and replace anything we can down to the smallest nut and bolt, rivets, and cracks in the airframe. Every inch of the rotor blades are inspected. During the PMI 2, we conduct a full serial number verification to match up all the components on the checklist."
In the past nine years, the UH-60s have gone from receiving phase maintenance once every 500 flight hours to 360 flight hour interval inspections. Before the aircraft goes in for phase, two 120 flight hour inspections are conducted by the line companies. With the increase of inspections and phases, the UH-60s started to use the Integrated Vehicle Health Maintenance System to better determine a components time before overhaul.
According to Rector, parts will be replaced based on what the actual condition is and not historical life. This system results in condition based maintenance. An onboard system monitors the health of individual components based on vibrations in order to catch the failure before a catastrophic failure.
"Each time we perform a phase, we challenge ourselves to see how clean we can get the aircraft," Dowdy said. "It is a great feeling to watch the helicopter fly on a test flight and return safely with no issues which lets us know we gave the line companies a good product."