A LEARJET-45 WITH TFE-731SER TYPE ENGINES EXPERIENCED FLUCTUATING LOW OIL PRESSURE. ACFT LANDED SAFELY. OIL DIPSTICK CAP FOUND NOT LOCKED DOWN.

Narrative

ROUGHLY 8 MINS INTO FLT; LEVEL AT 6000 FT THE OIL PRESSURE STARTED TO FLUCTUATE AND WAS OCCASIONALLY IN THE YELLOW (BELOW 60 PSI). ABOUT 14 MINS INTO THE FLT AFTER DSNDING TO 3000 FT AND WITH VISUAL OF THE ARPT; AND FLAPS SET AT 8 DEGS WE GOT A RED 'L ENG OIL PRESSURE LOW' CAS WITH NO TIME TO REVIEW THE CHKLIST AND IN A GOOD POS TO LAND WE CHOSE TO LAND; AND MONITORED THE OIL PRESSURE KNOWING THAT 50 PSI IS A MAGIC NUMBER; WHICH IT NEVER WENT BELOW. UPON COMPLETION OF THE PRE-LNDG CHKLIST AND LNDG SAFELY WE SHUT DOWN THE L ENG. TAXIED INTO THE RAMP AND SHUT DOWN THE REST OF THE PLANE. ONCE WE GOT OUT TO CHK THE PHYSICAL CONDITION OF THE L ENG; WE FOUND IT COVERED IN OIL FROM THE OIL SVC DOOR BACK. OPENING THE DOOR THE OIL DIPSTICK WAS IN THE HOLE BUT NOT LOCKED DOWN AND IT WAS VERY OBVIOUS THAT WAS THE SOURCE OF THE OIL LEAK. SAFELY GOT THE AIRPLANE ON THE GND WITH NO FURTHER DAMAGE. WE HAD CHKED THE OIL ON THE PREFLT; FOUND IT THE NORMAL OPS RANGE. AFTER CHKING THE OIL; FELT THE CAP HAD BEEN SECURED; HOWEVER IT APPEARS LATER IT MAY NOT HAVE BEEN. BE SURE THE OIL DIPSTICK CAP IS TOTALLY SECURED. WHEN IN LOW LIGHT CONDITIONS DOUBLE-CHK IT WITH A BRIGHT FLASHLIGHT; TO MAKE SURE THE SMALL TAB IS VISIBLE IN THE HOLE; AND THAT THE YELLOW INDEX LINES MATCH UP.