ACFT MAINT DISCREPANCY ACFT FLOWN PAST MAINT EXTENSION.

Narrative

THE ACFT BEING FLOWN IS A CESSNA 402. (THE ACFT ADHERES TO A 50 HR INSPECTION). ON FEB/MON/95; PRIOR TO ANY FLT; I WAS ASSIGNED AN ACFT THAT HAD 1.9 HRS REMAINING BEFORE INSPECTION. I ADDRESSED THIS SIT TO ONE OF THE MECHS; AND TOLD HIM THIS WAS NOT ENOUGH TIME FOR ME TO DO A TRIP AND COME BACK. THE MECH THEN AUTH AN EXTENSION OF THIS INSPECTION OF WHICH I WAS TO USE THE REMAINING 1.9 HRS PLUS A 5 HR EXTENSION TO RETURN. BEING NEW TO PART 135 OPS; I WASN'T SURE IN DETAIL HOW THIS EXTENSION WORKED. I ELECTED TO ASK A MECH IF; AFTER I DID A TRIP; DID I HAVE TO BRING THE PLANE BACK UNDER PART 91 WITH NO PAX IF I WAS TO RUN OUT OF TIME ON THE RETURN LEG HOME? HE SAID 'NO.' HE SAID THAT I COULD FLY THE PLANE UP TO 5 HRS PAST THE ORIGINAL INSPECTION DUE TIME - AS LONG AS YOU DON'T FLY PAST THE 5 HR EXTENSION. AFTER COMING BACK FROM A TRIP; OPS STILL DISPATCHED ME TO DO 2 OTHER TRIPS THAT DAY KNOWING THE FACT I WAS FLYING AN ACFT ON A 5 HR EXTENSION. (NEITHER THE MECH NOR OPS INFORMED ME THAT I SHOULD HAVE GONE BACK TO THE HANGAR ONCE THE ACFT RETURNED TO ITS HOME BASE - PLANE SHOULD HAVE BEEN GNDED). THE IMPRESSION THEY WERE GIVING ME WAS THAT I COULD FLY UP UNTIL THE END OF THE 5 HR EXTENSION. MY LAST TRIP THAT DAY ON FEB/MON/95 REQUIRED AN OVERNIGHT AT THE DEST. THE FOLLOWING MORNING; FEB/TUES/95; I RETURNED TO HOME BASE WHERE I STILL HAD APPROX 2 HRS REMAINING ON THE EXTENSION. (OPS NONETHELESS; STILL WANTED ME TO DO 1 MORE TRIP. I TOLD OPS THAT I COULDN'T DO ANOTHER TRIP (BECAUSE I DIDN'T HAVE ENOUGH TIME ON THE ACFT) AND THAT THE PLANE NEEDED TO GO TO THE HANGAR. OPS AGREED WITH ME. BEFORE TAKING THE ACFT BACK; THE FAA RAMP CHKED MY ACFT. THEY DID A WALK AROUND; LISTED AND POINTED OUT SOME SQUAWKS AND WANTED TO LOOK AT THE ACFT LOG. THEY DISCOVERED THAT THE ACFT WAS OVERDUE. AT THAT TIME THE FAA INSPECTORS BRIEFED ME IN HOW THIS 5 HR EXTENSION IS SUPPOSED TO WORK. BASICALLY THE EXTENSION IS PRIMARILY USED TO PREVENT AN ACFT FROM BEING GNDED DUE TO BEING TIMED OUT AT A PLACE OTHER THAN THE ACFT'S HOME BASE. ONCE THE ACFT DOES RETURN TO ITS HOME BASE; IT MUST BE GNDED FOR THE INSPECTION AT THAT TIME. IT CANNOT BE DISPATCHED AGAIN.