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.