Routine Oil Change, Non-routine Result

A regional evangelical association flew their Piper Aztec in for a routine oil change this morning. MMS regularly maintains and inspects their Aztec. Upon positioning the aircraft in the hangar Tim noticed a pattern of fresh oil on the underside of the left wing culminating in oil dripping from the trailing edge of the flap.

Going ahead with the oil change, Tim brought MMS Chief Inspector, Dennis Satterthwaite, into the picture and the two of them gave the engine an in-depth inspection. With suspicions of a cracked oil cooler, Tim and Dennis isolated the oil cooler, hooked up shop air, and prepared to simulate the 100 pounds of oil pressure that would normally push through the cooler. At 40 pounds a drip began to seep from the the cooler. At 60 pounds it was a steady flow. Tim and Dennis surmise that at 100 pounds a steady spray of oil would have been hitting the firewall, draining through the landing gear doors, and exiting off the wing.

Tim positions the aircraft in Hangar A.

Tim drains the oil from the left engine.

Tim and Dennis inspect the engine.

Testing the oil cooler with shop air.

After checking local suppliers for a new oil cooler, a new cooler had to be ordered from California and will be delivered tomorrow. Lord willing, the Aztec will be back in the sky shortly after the oil cooler arrives.

This is the kind of thing we look for and are glad to find. Routine maintenance is done routinely in order to find the non-routine. It's a blessing to have the facility, the expertise, and God's enabling to serve the mission community by making sure its airplanes are airworthy and safe to fly. In tomorrow's post I hope to show the installation on the new oil cooler and then the return of the aircraft to mission service!