AIRFRAME
If we suspect that the irreversible valve attached to the actuator assembly is at fault, measure the temperature diff erence between the pressure and return lines. If one is higher than the other, check the other irreversible valves and compare the temperatures. This could pinpoint the problem unit.
Relief valves are also a culprit that can generate heat in
hydraulic system component. We obviously have not covered all possibilities concerning
internal hydraulic leaks, but we have a path to quickly look at the systems major components. If you have any problems with internal hydraulic leaks, please feel free to contact me at
robertwpeterson69@yahoo.com.
Photo: Courtesy of the Canby Herald by Ray Hughey
Robert Peterson entered the aviation fi eld when he was drafted in 1963, despite being in college working towards a degree in mechanical engineering. He joined the U.S. Air Force and went to technical school on hydraulics and spent fi ve years working on hydraulic systems on a virtual air show of aircraft. The F-4, F-105, F-106, F-102, B-52, KC-135, C-130, C-54, C-47, H-19 and the H-43, among others. If a new air aircraft came in, Peterson volunteered to work on it.
Hydraulic Filter
In the picture of the fi lter assembly, measure the pressure coming from the hydraulic pump, through the fi lter assembly and out to the hydraulic system. The temperature between the inlet and outlet should be within about 15 degrees of each other. If we see a diff erence in the temperatures greater than 15 degrees, there is a strong possibility the fi lter element is starting to load up with contaminants.
After leaving the military, Peterson went back to college to get his A&P certifi cation and arrived at Columbia Helicopters in 1972. In 18 months, he became the hydraulic shop chief and held that position for more than 30 years. Peterson was a member of the Air National Guard for 31 years and is a member of the Standards of American Engineering (Aerospace Actuation, Control and Fluid Power Systems) A-6. He is currently under contract with Sunset Helicopters Inc. in Aurora, OR.
“We use Airwolf’s TT Straps and are glad that someone is helping keep our Bell helicopters flying while reducing costs.”
— Alfonso Garcia, Great Slave Helicopters.
Airwolf 204/205/212, UH-1, AH-1 TT Straps Now FAA STC’d and IN STOCK
36 Month Bell 206/206L, OH-58 Straps also in stock.
Phone: 440-632-1687 •
www.airwolfaerospace.com 8
HelicopterMaintenanceMagazine.com April | May 2015
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