MIL MIL-DTL-8815/33 covers hydraulic filter elements for the Aviation Ground Power Unit (AGPU). This specification describes:A multi-pass filtration performance test under cyclic flow and vibration conditions with continuous contaminant injection for hydraulic fluid power filter elements;A procedure for determining the contaminant capacity, particulate removal and differential pressure characteristics; andSpecific changes, revisions, and modifications to paragraphs of Military Specification MIL-F-8815D.