Narrative:

My captain and I flew 2 passenger carrying legs of a trip without complying with a required maintenance MEL procedure. It took an FAA line check by a maintenance inspector to point out to us that we had done so, and were about to fly a third leg without doing so. We had an inoperative main system hydraulic pressure gauge. We often fly several different airplanes each trip, many of which have MEL write-ups. Most of the MEL write-ups really are simple, common sense items that require no special procedures. We always check to see what is written up, and should always read the MEL to see if there are any special procedures. In this case, the captain mentioned to me that the main system hydraulic pressure gauge had a little bit of hydraulic fluid leaking into it. It had been written up by the last crew and I really didn't think much of it, and neither did he. We proceeded with 2 legs of our trip. An FAA maintenance inspector rode with us on the third leg, and before we started, he asked us about the procedure required before engine start with the gauge inoperative, and neither of us knew it. We pulled out the MEL, and sure enough, there is an important, required procedure to follow to be sure the hydraulic system was working properly, and that we would have hydraulics for the flight. It was obvious to the inspector we had not done this previously. To top that off, the captain and I failed to lock our cockpit doors, which is a new procedure for us before takeoff. We used to lock them after takeoff, and it's not on our new checklist.

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Original NASA ASRS Text

Title: AN ACR LTT CREW WAS CHALLENGED BY AN ACR MAINT INSPECTOR ON THEIR KNOWLEDGE OF THEIR MEL PROCS.

Narrative: MY CAPT AND I FLEW 2 PAX CARRYING LEGS OF A TRIP WITHOUT COMPLYING WITH A REQUIRED MAINT MEL PROC. IT TOOK AN FAA LINE CHK BY A MAINT INSPECTOR TO POINT OUT TO US THAT WE HAD DONE SO, AND WERE ABOUT TO FLY A THIRD LEG WITHOUT DOING SO. WE HAD AN INOP MAIN SYS HYD PRESSURE GAUGE. WE OFTEN FLY SEVERAL DIFFERENT AIRPLANES EACH TRIP, MANY OF WHICH HAVE MEL WRITE-UPS. MOST OF THE MEL WRITE-UPS REALLY ARE SIMPLE, COMMON SENSE ITEMS THAT REQUIRE NO SPECIAL PROCS. WE ALWAYS CHK TO SEE WHAT IS WRITTEN UP, AND SHOULD ALWAYS READ THE MEL TO SEE IF THERE ARE ANY SPECIAL PROCS. IN THIS CASE, THE CAPT MENTIONED TO ME THAT THE MAIN SYS HYD PRESSURE GAUGE HAD A LITTLE BIT OF HYD FLUID LEAKING INTO IT. IT HAD BEEN WRITTEN UP BY THE LAST CREW AND I REALLY DIDN'T THINK MUCH OF IT, AND NEITHER DID HE. WE PROCEEDED WITH 2 LEGS OF OUR TRIP. AN FAA MAINT INSPECTOR RODE WITH US ON THE THIRD LEG, AND BEFORE WE STARTED, HE ASKED US ABOUT THE PROC REQUIRED BEFORE ENG START WITH THE GAUGE INOP, AND NEITHER OF US KNEW IT. WE PULLED OUT THE MEL, AND SURE ENOUGH, THERE IS AN IMPORTANT, REQUIRED PROC TO FOLLOW TO BE SURE THE HYD SYS WAS WORKING PROPERLY, AND THAT WE WOULD HAVE HYDS FOR THE FLT. IT WAS OBVIOUS TO THE INSPECTOR WE HAD NOT DONE THIS PREVIOUSLY. TO TOP THAT OFF, THE CAPT AND I FAILED TO LOCK OUR COCKPIT DOORS, WHICH IS A NEW PROC FOR US BEFORE TKOF. WE USED TO LOCK THEM AFTER TKOF, AND IT'S NOT ON OUR NEW CHKLIST.

Data retrieved from NASA's ASRS site as of July 2007 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.