AN A320 IN POS AND HOLDING FOR TKOF AT ORD RWY 4L GUARDS THE WRONG FREQ WITH THE TWR. CTLR THEN ISSUED A GAR TO AN ACFT ON SHORT FINAL.

Narrative

AFTER ACFT PUSH FROM GATE; INITIAL TAXI CLRNC FROM GND CTL WAS TO TAXI TO RWY 9L VIA TXWYS A; A6; AND J. THIS IS A RELATIVELY SHORT TAXI; BUT WE WERE 4TH IN LINE FOR THE RWY. DURING THIS TIME; WE WERE INSTRUCTED BY GND TO MONITOR TWR ON FREQ 126.9. SINCE THE BEFORE TKOF CHKLIST WAS BEING PERFORMED AND WE WERE 4TH IN LINE FOR RWY 9L; I DID NOT IMMEDIATELY CHANGE THE RADIO TO THE NEW FREQ. ABOUT 30 SECONDS LATER; GND AGAIN TOLD US TO MONITOR FREQ 126.9; AT WHICH POINT I CHANGED CHANNELS. ONCE ON TWR FREQ; TWR ASKED WHY WE WEREN'T TURNING R ON TXWY W FOR RWY 4L. I SURMISED TWR MUST HAVE GIVEN THESE CHANGE OF RWY INSTRUCTIONS PREVIOUSLY WHILE WE WERE STILL ON GND (121.75). IN THE AIRBUS THE COMPUTERS MUST BE REPROGRAMMED FOR THE NEW RWY; AS WELL AS NEW TKOF DATA CALCULATED; FLAP SETTINGS AND TKOF SPDS. THE LENGTH OF TXWY W TO RWY 4L IS ONLY ABOUT 200 YARDS. WHILE THESE COMPUTATIONS WERE BEING PERFORMED; TWR CLRED US FOR POS AND HOLD RWY 4L. AT THIS TIME; I THOUGHT TWR GAVE A NEW TWR FREQ OF 127.4 FOR TKOF. I ASKED THE CAPT IF HE CONCURRED; AND HE DID; SO I ANSWERED AND CHANGED FREQ. WHILE ON THE RWY AWAITING TKOF CLRNC; I HEARD DEP TALKING TO AN ACFT WITH A SIMILAR CALL SIGN TO OURS. I THEN REALIZED WE WERE ON A WRONG FREQ AND WENT BACK TO TWR ON 126.9. TWR ASKED WHERE WE HAD BEEN AND SAID HE HAD GIVEN TKOF CLRNC TO US; BUT SINCE WE HAD NOT ACKNOWLEDGED HE HAD TO SEND ONE ACFT AROUND. TWR CANCELED OUR TKOF CLRNC; BUT THEN IMMEDIATELY REISSUED; 'CLRED FOR TKOF RWY 4L; HDG 070 DEGS;' AT WHICH POINT TKOF OCCURRED WITHOUT INCIDENT. I FEEL TWR NEEDS TO UNDERSTAND THAT WHEN REISSUING OR CHANGING RWYS FOR AN AUTOMATED ACFT LIKE THE AIRBUS; A LOT NEEDS TO BE ACCOMPLISHED IN A VERY SHORT TIME AND THAT NEEDS TO BE COMPENSATED FOR DURING THEIR EXPEDITED OPS. SUPPLEMENTAL INFO FROM ACN 434472: APCHING TXWY W ON TXWY J WE WERE TOLD (A BIT CURTLY) TO TURN R ON TXWY W FOR RWY 4L. THIS WAS THE FIRST TIME WE HAD HEARD ANY MENTION OF RWY 4L. WE TURNED ON TXWY W AND THE FO BEGAN TO ENTER THE NEW DATA AND RE-DO THE TKOF CHKLIST; FINISHING IT AS WE TAXIED INTO POS. ABOUT THAT TIME WE THOUGHT WE HEARD A NEW FREQ FOR US. WHAT I THOUGHT I HEARD WAS A NEW DEP CTL FREQ ASSIGNMENT (127.4); WHICH DIDN'T SURPRISE ME BECAUSE IT WAS SUNDAY AND THEY OFTEN COMBINE DEP SECTORS ON WKENDS. WHAT I THINK HAPPENED NEXT WAS THAT THE FO; RELATIVELY INEXPERIENCED IN ACR OPS AND THIS AIRPLANE AND ORD IN PARTICULAR; SOMEHOW THOUGHT THIS NEW FREQ WAS GIVEN BECAUSE OF THE LAST MIN RWY CHANGE; AND THOUGHT IT WAS RWY 4L'S FREQ; AND SO CHANGED TO IT. HE EVEN ASKED ME IF HE'D GOTTEN IT CORRECT ('127.4?'). I NODDED YES; MEANING I HAD HEARD THE SAME 127.4. HE APPARENTLY TOOK THAT TO MEAN THAT I HAD ALSO THOUGHT THAT WE WERE TO CHANGE TO THAT FREQ NOW; WHICH HE DID. WHEN HE CHANGED THE FREQ; I THOUGHT HE WAS MERELY ENTERING IT IN THE STANDBY FREQ WINDOW SO THAT IT WOULD BE READY TO SWITCH TO WHEN AIRBORNE. THE RESULT WAS THAT WE HELD ON THE RWY FOR A MIN OR SO; EFFECTIVELY 'NORDO;' CAUSING ANOTHER ACFT TO HAVE TO GO AROUND. AN ACFT HOLDING SHORT ON TXWY E CAUGHT MY ATTN BY FLASHING HIS LNDG LIGHT; AND WE BEGAN LOOKING AROUND THE COCKPIT FOR SOMETHING AWRY; AND FOUND THE WRONG FREQ SET. WE PUT THE CORRECT ONE IN AND CHKED IN WITH TWR (AND GOT A SNIDE REMARK BACK). THE CONFIGN AT THE TIME AT ORD WAS: DEPARTING RWYS 4L; 9L; 32L AND 14L. LNDG RWYS 4L; 4R; 9L AND (I THINK) RWY 9R. THIS TYPE AND TEMPO OF OP LEAVES VIRTUALLY NO ROOM FOR ERROR. THAT WE HAVE AS FEW AS WE DO IS A CREDIT TO BOTH THE CTLRS AND AIR CREWS WHO (USUALLY) PERFORM AT THEIR VERY BEST. IT'S JUST TOO BAD ARPTS LIKE ORD HAVE TO OPERATE AT THE EDGE OF THE ENVELOPE SO MUCH OF THE TIME.