Narrative:

During cockpit setup, I inadvertently reversed last 2 numbers of squawk. Captain also missed the reversal on before takeoff check. Cleared to taxi to runway 22L via taxiway D. Second of 2 aircraft in runway 27L pad was just entering pad as we approached pad. About halfway along the pad, we checked final, saw an ATR on short final to runway 27L and told tower to cancel our takeoff clearance. Tower complied and after a few seconds asked where we were. We were just turning corner at end of taxiway D to approach runway 22L. So informed tower and after ATR landed, tower again told fly heading 270 degrees, cleared takeoff runway 22L which I read back. After takeoff there was an unusually long, for ord, delay switching us to departure. Captain asked tower if they had us. New voice said turn southerly, 180 degrees I believe, hurry to 5000 ft. Captain and I both thought 270 degrees from runway 22L for eastbound flight a bit unusual, so were watching TCASII closely. Tower said check transponder. Captain saw the error, and corrected it. We saw no conflict either visually or on TCASII. We were given further turns east and continued without incident. New procedure at ord said don't read pre departure clearance information to clearance, just tell metering if clearance received. I did so, giving the squawk which I read from transponder readout window. In future, I am going to check both paper and transponder to backup other pilot and confirm no error.

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Original NASA ASRS Text

Title: NEW PROC FOR PDC AT ORD COMPLICATED BY MD80 CREW WHEN FO REVERSES LAST 2 NUMBERS ON HIS XPONDER. ATC THINKS THEY ARE GOING TO ANOTHER DEST AND GIVES THEM A WESTERLY RADAR VECTOR FOR AN EBOUND FLT.

Narrative: DURING COCKPIT SETUP, I INADVERTENTLY REVERSED LAST 2 NUMBERS OF SQUAWK. CAPT ALSO MISSED THE REVERSAL ON BEFORE TKOF CHK. CLRED TO TAXI TO RWY 22L VIA TXWY D. SECOND OF 2 ACFT IN RWY 27L PAD WAS JUST ENTERING PAD AS WE APCHED PAD. ABOUT HALFWAY ALONG THE PAD, WE CHKED FINAL, SAW AN ATR ON SHORT FINAL TO RWY 27L AND TOLD TWR TO CANCEL OUR TKOF CLRNC. TWR COMPLIED AND AFTER A FEW SECONDS ASKED WHERE WE WERE. WE WERE JUST TURNING CORNER AT END OF TXWY D TO APCH RWY 22L. SO INFORMED TWR AND AFTER ATR LANDED, TWR AGAIN TOLD FLY HDG 270 DEGS, CLRED TKOF RWY 22L WHICH I READ BACK. AFTER TKOF THERE WAS AN UNUSUALLY LONG, FOR ORD, DELAY SWITCHING US TO DEP. CAPT ASKED TWR IF THEY HAD US. NEW VOICE SAID TURN SOUTHERLY, 180 DEGS I BELIEVE, HURRY TO 5000 FT. CAPT AND I BOTH THOUGHT 270 DEGS FROM RWY 22L FOR EBOUND FLT A BIT UNUSUAL, SO WERE WATCHING TCASII CLOSELY. TWR SAID CHK XPONDER. CAPT SAW THE ERROR, AND CORRECTED IT. WE SAW NO CONFLICT EITHER VISUALLY OR ON TCASII. WE WERE GIVEN FURTHER TURNS E AND CONTINUED WITHOUT INCIDENT. NEW PROC AT ORD SAID DON'T READ PDC INFO TO CLRNC, JUST TELL METERING IF CLRNC RECEIVED. I DID SO, GIVING THE SQUAWK WHICH I READ FROM XPONDER READOUT WINDOW. IN FUTURE, I AM GOING TO CHK BOTH PAPER AND XPONDER TO BACKUP OTHER PLT AND CONFIRM NO ERROR.

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.