What was found
.1250 INCH ALUMINUM LINE WHICH CONNECTS BETWEEN ENGINE CRANKCASE AND FLEXIBLE LINE GOING TO OIL PRESSURE GAUGE BROKE IN-FLIGHT CAUSING LOSS OF APPROXIMATELY 5 QUARTS (OUT OF TEN) OF OIL BEFORE AIRCRAFT COULD BE LANDED. SUBMITTER FEELS AN AD REQUIRING REPLACEMENT OF THE METAL LINE WITH A SUITABLE FLEXIBLE LINE SHOULD BE GENERATED. THIS FAILURE OCCURRED INSIDE AN ADEL CLAMP MAKING PRE-FLIGHT INSPECTION DIFFICULT.