A CL65 ON ROTATION DECLARED AN EMER AND DIVERTED DUE TO A L 14TH STAGE DUCT LEAK WARNING CAUSED BY A DUCT COVER MISSING AND LOOP SENSING ELEMENT TOUCHING THE DUCT.

Narrative

ON OUR MORNING RPT TO OUR COMPANY AT ZZZ; THE CONTRACT MECH HAD THE ACFT ALREADY PWRED UP AND HAD THEN COMPLETELY SHUT IT BACK DOWN. AS I WAS PWRING THE APU UP AGAIN; HE COMES TO THE FLT DECK AND SAID HE GOT A 'L 14TH DUCT' WARNING COME ON AND STAY ON. WHEN I XFERRED TO THE APU GENERATOR; THE 'L 14TH DUCT' WARNING CAME ON; THEN APPROX 10-15 MINS LATER WENT OUT. THE MECH THEN WENT OUT TO CONSULT WITH OUR COMPANY MECHS. HE THEN CAME BACK AND TOLD US TO COMPLETELY SHUT DOWN THE ACFT SO HE COULD INSPECT SOME DUCT AND WIRING IN THE TAIL. AFTER WE SHUT DOWN AND THE MECH COMPLETED HIS INSPECTION (FOUND NOTHING); WE PWRED THE ACFT UP FOR THE THIRD TIME; AND UPON APU GENERATOR SWITCHING; THIS TIME WE DID NOT GET THE WARNING. AFTER 10-15 MINS; STILL NO WARNING. IN DISCUSSIONS WITH THE MECH; HE SAID OUR COMPANY MECHS BASICALLY WERE OF THE OPINION THAT SINCE THERE IS NO HISTORY ON THIS PROB; IT SHOULD BE GOOD TO SIGN OFF SINCE THE THIRD TIME IT DID NOT APPEAR! I TOLD THE MECH THAT MY CONCERN IS THAT IF THIS COMES UP INFLT; OUR PROCS CALL FOR IDLE PWR ON THE AFFECTED ENG OR POSSIBLE ENG SHUTDOWN; AND IF I DO GET IT INFLT; I WILL DO IT EVEN THOUGH IT LOOKS DOWN HERE ON THE GND LIKE AN ELECTRICAL GLITCH! AFTER DISCUSSING ABORT PROCS WITH MY FO AND SEVERAL OTHER ITEMS; WE ACCEPTED THE SIGN-OFF; BOTH OF US AGREEING THAT IF THE WARNING COMES UP AT ALL REGARDLESS OF THE LENGTH OF TIME DURING THE START-UP AND TAXI OUT TO THE RWY; WE WILL TURN AROUND BACK TO THE GATE! EVERYTHING WAS NORMAL UNTIL RIGHT AT ROTATION; THE WARNING 'L 14TH DUCT' APPEARED. WE PERFORMED A NORMAL CLBOUT; CLEANED THE ACFT UP; TOLD ATC WE NEEDED TO RETURN TO THE ARPT. MY FO SUGGESTED DECLARING AN EMER; WHICH WE DID; AND GOT ATC TO LEVEL US OFF AT 5000 FT AND GAVE US A HDG FOR VECTORS TO THE ILS RWY 23. THE FO WAS THE PNF; SO HE RAN ALL THE CHKLIST ITEMS UP TO CRUISE; THEN RAN THE PROC FOR THE 'L 14TH DUCT' WARNING. WE DECIDED NOT TO SHUT THE ENG DOWN NOR REDUCE THE THRUST TO IDLE SINCE WE WERE 10 MINS FROM LNDG; NO ANTI-ICE NEEDED AND PAST HISTORY; SO HE RAN THE PROC UP TO SINGLE ENG PROCS. ON VECTORS FOR THE ILS; THE WARNING WENT AWAY AND STAYED AWAY. WE LANDED 5 MINS LATER. LATER INSPECTION SHOWED A SECTION OF THE 14TH STAGE BLEED DUCT COVERING MISSING AND THE DUCT LOOP TOUCHING THAT SECTION OF DUCTING. IN OUR DEBRIEFING (CAPT AND FO); WE DISCOVERED THAT THE FO RAN THE WRONG PROC. THERE WAS A TEMPORARY REVISION FOR THIS PROC (YELLOW COLORED PAGES) RIGHT NEXT TO THE NORMAL PROC; BUT THE NORMAL PROC WAS NOT CROSSED OUT NOR EVEN BETTER WAS NOT REMOVED. ALSO; WITH VISIBILITY AT 1 MI AND THE WINDS AT 050 DEGS AT 3 KTS; I NEVER THOUGHT TO USE RWY 5. RWY 23 VISIBILITY WAS 1 MI (CAT D) WHILE RWY 5 WAS 1/2 MI. ALSO; MDA (DECISION HT) FOR RWY 23 WAS 462 FT WHILE RWY 5 WAS 200 FT. CEILINGS WERE RPTED AT 100 FT OVCST. THESE POTENTIALLY CRITICAL OVERSIGHTS WERE OVERLOOKED AND MISSED IN THE RUSH TO GET SET UP FOR THE APCH. WE SAW THE RWY APPROX 200 FT ABOVE DECISION HT ON RWY 23. AND THE 'L 14TH DUCT' WARNING.