AN EMB 140 WAS DISPATCHED WITH THE APU OIL CAP NOT SECURED. UNIT SHUT DOWN FOR LOW OIL QUANTITY. UNIT OPERATED FOR 25 LEGS BEFORE SHUTDOWN.

Narrative

ACFT WAS SCHEDULED FOR A PS-2 CHK AT BASE. I SVCED OIL ON ENGS AND APU. THE ACFT THEN PROCEEDED FOR DEP; AND FLEW WITHOUT PROBS ON THURSDAY; FRIDAY; AND SATURDAY. ON SUNDAY; THE ACFT WAS SCHEDULED AGAIN FOR A PS-1 CHK. IT THEN PROCEEDED FOR DEP TOWARDS ZZZ1 WHERE IT EXPERIENCED A SHUTDOWN OF THE APU (I AM UNSURE IF IT WAS INFLT OR ON GND). THE MECHS AT ZZZ1 THEN PROCEEDED TO EXAMINE THE OCCURRENCE AND FOUND THE OIL CAP FOR THE APU TO BE UNSECURED. I HAVE NOT BEEN ABLE TO REVIEW THE LOGBOOK FOR THIS ACFT; BUT I DID NOT FIND ANY ENTRIES THAT INDICATE ANYBODY ELSE SVCED EITHER ENGS OR APU FOR OIL AND; AT THIS POINT; ALL EVIDENCE POINTS TO ME BEING AT FAULT FOR INCORRECTLY SECURING THE APU OIL SVC CAP AND IT MAY HAVE RATTLED OPEN AFTER LEAVING THE STATION; POSSIBLY DURING ANY ONE OF THE 25 LEGS IT FLEW FROM THE TIME I SVCED OIL ON THE APU UNTIL IT WAS DISCOVERED; 3 DAYS LATER -- OR MAYBE ANOTHER MECH SVCED OIL ON THE APU SOMETIME AFTER MY PS-2 CHK AND IT IS NOT MY FAULT. THIS RINGS POSSIBLE BUT; LIKE I STATED EARLIER; I COULD NOT FIND EVIDENCE TO SUPPORT THIS CLAIM.