Narrative:

A couple of min prior to pushback, the tug driver entered the cockpit to inform me that 1 of the 'pitot tubes' was cracked on the captain's side. After a brief discussion with my first officer about not noticing any airspeed/altitude indication abnormalities on previous legs, I went outside to investigate. I looked at the pitot tubes and saw no cracks. The tug driver then pointed to the aoa vane where a crack was present along the inboard side for about 1/4- 1/2 the distance from the leading edge to the trailing edge. The following was obvious to me from my inspection: we had been flying the aircraft with the cracked vane for at least 1 leg and possibly more: the vane had been 'flight tested' and was completely secure and operational. The introduction to our MEL has discussions concerning 'inoperative' items and ability of components to perform 'intended functions.' I decided that this component was/had been capable of 'intended function' (albeit cracked) and not subject to MEL. I decided it was safe and proper to continue on to that leg's destination (phx) and inform our maintenance upon arrival. This I did and wrote up the cracked vane upon arrival in phx where maintenance replaced the vane. Later, in my discussions with maintenance/management, I learned that I probably erred in not calling maintenance/dispatch about the vane prior to pushback from my departure point. This is the reason I write this report. In hindsight, I agree that I did make a mistake in my on-the-spot mental interpretation of MEL/logbook write-up requirements/procedures. I believe that the desire to push on time resulted in a hasty, twisted interpretation in my mind as to what the MEL says relating to a captain's judgement involved in deciding to fly an aircraft and maintenance logbook entry requirements.

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Original NASA ASRS Text

Title: RPTR ERROR ADMITTED IN NOT REPLACING DEFECTIVE ANGLE OF ATTACK VANE PRIOR TO FLT.

Narrative: A COUPLE OF MIN PRIOR TO PUSHBACK, THE TUG DRIVER ENTERED THE COCKPIT TO INFORM ME THAT 1 OF THE 'PITOT TUBES' WAS CRACKED ON THE CAPT'S SIDE. AFTER A BRIEF DISCUSSION WITH MY FO ABOUT NOT NOTICING ANY AIRSPD/ALT INDICATION ABNORMALITIES ON PREVIOUS LEGS, I WENT OUTSIDE TO INVESTIGATE. I LOOKED AT THE PITOT TUBES AND SAW NO CRACKS. THE TUG DRIVER THEN POINTED TO THE AOA VANE WHERE A CRACK WAS PRESENT ALONG THE INBOARD SIDE FOR ABOUT 1/4- 1/2 THE DISTANCE FROM THE LEADING EDGE TO THE TRAILING EDGE. THE FOLLOWING WAS OBVIOUS TO ME FROM MY INSPECTION: WE HAD BEEN FLYING THE ACFT WITH THE CRACKED VANE FOR AT LEAST 1 LEG AND POSSIBLY MORE: THE VANE HAD BEEN 'FLT TESTED' AND WAS COMPLETELY SECURE AND OPERATIONAL. THE INTRODUCTION TO OUR MEL HAS DISCUSSIONS CONCERNING 'INOP' ITEMS AND ABILITY OF COMPONENTS TO PERFORM 'INTENDED FUNCTIONS.' I DECIDED THAT THIS COMPONENT WAS/HAD BEEN CAPABLE OF 'INTENDED FUNCTION' (ALBEIT CRACKED) AND NOT SUBJECT TO MEL. I DECIDED IT WAS SAFE AND PROPER TO CONTINUE ON TO THAT LEG'S DEST (PHX) AND INFORM OUR MAINT UPON ARR. THIS I DID AND WROTE UP THE CRACKED VANE UPON ARR IN PHX WHERE MAINT REPLACED THE VANE. LATER, IN MY DISCUSSIONS WITH MAINT/MGMNT, I LEARNED THAT I PROBABLY ERRED IN NOT CALLING MAINT/DISPATCH ABOUT THE VANE PRIOR TO PUSHBACK FROM MY DEP POINT. THIS IS THE REASON I WRITE THIS RPT. IN HINDSIGHT, I AGREE THAT I DID MAKE A MISTAKE IN MY ON-THE-SPOT MENTAL INTERP OF MEL/LOGBOOK WRITE-UP REQUIREMENTS/PROCS. I BELIEVE THAT THE DESIRE TO PUSH ON TIME RESULTED IN A HASTY, TWISTED INTERP IN MY MIND AS TO WHAT THE MEL SAYS RELATING TO A CAPT'S JUDGEMENT INVOLVED IN DECIDING TO FLY AN ACFT AND MAINT LOGBOOK ENTRY REQUIREMENTS.

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.