Narrative:

Taxied air carrier xx heavy into position and hold runway 32R because he was not ready for takeoff and told him to advise ready. 10 mins later he called ready. I told him to continue holding. I then cleared medium large transport for takeoff and I then cleared air carrier yxx heavy runway 32L T1 intersection for takeoff. When I looked behind me air carrier xx heavy was departing and medium large transport was flying right over air carrier xx heavy. Supplemental information from acn 197456. (Our flight was air carrier xx heavy). Ord tower asked us if air carrier xx heavy was ready for takeoff. We were not ready (load, checklist) and so advised tower. Tower cleared air carrier xx heavy into position runway 32R and hold. We acknowledged and went into position. After final load was received and reviewed, checklist completed, first officer notified tower 'air carrier xx heavy ready for takeoff.' tower replied 'roger, I'll get right back to you.' shortly after that exchange, crew heard tower say 'air carrier xx heavy, right turn, heading 340, cleared for takeoff.' first officer read back clearance verbatim. Captain scanned cockpit, asked if crew was ready. On affirmative from each, takeoff was started. As aircraft passed intersection of 32R/9L, crew observed medium large transport taking off on 9L, gear retraction almost complete when first sighted. Medium large transport passed over and behind us while we continued to accelerate for normal takeoff. After airborne, tower advised to turn to 360 and that we had taken the clearance for Y heavy. First officer replied we had a clearance for air carrier xx heavy and had read that back. Tower again said 'the clearance was for Y heavy -- no problem.' but there was a problem, and that is why this report is filed. Because we had been on tower frequency for so long, we had no awareness of the other aircraft with a similar call sign. Remaining on ground control and off the runway until ready for takeoff would have helped in this situation. Also, a takeoff stop/hold -- go light would have prevented this conflict. Supplemental information from acn 197454. Air carrier xx while taxiing towards runway 32R at ord, tower asked if we were ready for takeoff. We had not received our load close out and advised the tower we were not ready for takeoff. Despite this, tower advised us to taxi into position and hold. (The crew discussed this unusual situation of holding on a runway when not ready for departure). The load close out arrived, we completed our checklists, and advised the tower we were ready for departure. At this point in time ord field was conducting simultaneous and intersecting runway departures. Our flight, air carrier xx heavy, was unaware of the aircraft air carrier yxx heavy holding in position on runway 32L. After advising the tower we were ready for takeoff, tower replied, 'air carrier xx heavy will get right back to you.' a short time later the following takeoff clearance was heard by the 4 people in the cockpit wearing earphones. Tower: 'air carrier xx heavy, turn right heading 340 degree, cleared for takeoff.' the clearance was read back. The captain asked if everyone was ready and with positive replies we proceeded to takeoff at the intersection of 32R and runway 9L. The medium large transport passed over the tip of us by 200 ft. The takeoff clearance we received was apparently for air carrier yxx heavy. The following are contributing factors. Similar sounding call signs. Aircraft on intersecting runways holding for takeoff simultaneously. Split tower frequencys (we were unaware of medium large transport departing runway 9L). Absence of runway issued in takeoff clearance. Lack of action when takeoff clearance was read back. The following corrective actions should be implemented. During simultaneous intersecting ry departures, extreme care should be taken with aircraft having like call signs. 2 aircraft on intersecting runways holding for takeoff should be made aware of each other. Stop lights, like in europe, should be constructed. Supplemental information from acn 197459. After we were airborne, tower advised us that we had taken off on air carrier yxx heavy's clearance. The first officer answered that he was certain that we had received and acknowledged the clearance as air carrier xx heavy. Tower repeated that it hd been for yxx, and added, '...but no problem.' for a moment, that seemed to say that it was only a single digit cll sign mix-up on tower's part. But when we switched frequencys, departure control also advised us that the clearance had been for air carrier yxx heavy. Looking left, we saw another widebody transport that had just taken off 32L and decided that he was yxx and probably he had, in fact, taken off on our clearance. At no timeon the ground do I recall hearing any reference to air carrier yxx heavy or the aircraft on runway 4L. Supplemental information from acn 197458. Medium large transport approached the runway 4L hold line, ord tower cleared 'aircraft' for takeoff then us into 'position and hold.' as I was making a slow right turn to line up, tower cleared us for takeoff. I pushed the throttles forward gave the aircraft to the first officer and we started our roll. At about half way down the runway I saw a widebody transport on his takeoff roll on 32R. I determined that the safest course of action would be to continue the takeoff. We passed right over the top of the widebody transport at about 150 ft. When I questioned ord tower about the incident they replied that the aircraft had only been cleared 'position and hold.' they had misunderstood takeoff clearance for an aircraft with a similar sounding call sign, on another runway. Tower personnel should keep their eyes on all aircraft that are holding in position. Ord tower never said a word! Supplemental information from acn 197554. Medium large transport was cleared into position runway 9L at ord. As we turned onto the runway, ord tower cleared us for takeoff. During the takeoff roll, the captain pointed out another aircraft departing on runway 32R which crossed our runway. We continued our takeoff because an abort would have caused us to strike the other aircraft.

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Original NASA ASRS Text

Title: ACR XX UNAUTH TKOF ON MULTIPLE RWY OP INTERSECTING PARALLEL RWYS HAD LTSS FROM MLG. PLTDEV. SIMILAR A/N. NMAC.

Narrative: TAXIED ACR XX HVY INTO POS AND HOLD RWY 32R BECAUSE HE WAS NOT READY FOR TKOF AND TOLD HIM TO ADVISE READY. 10 MINS LATER HE CALLED READY. I TOLD HIM TO CONTINUE HOLDING. I THEN CLRED MLG FOR TKOF AND I THEN CLRED ACR YXX HVY RWY 32L T1 INTXN FOR TKOF. WHEN I LOOKED BEHIND ME ACR XX HVY WAS DEPARTING AND MLG WAS FLYING RIGHT OVER ACR XX HVY. SUPPLEMENTAL INFO FROM ACN 197456. (OUR FLT WAS ACR XX HVY). ORD TWR ASKED US IF ACR XX HVY WAS READY FOR TKOF. WE WERE NOT READY (LOAD, CHKLIST) AND SO ADVISED TWR. TWR CLRED ACR XX HVY INTO POS RWY 32R AND HOLD. WE ACKNOWLEDGED AND WENT INTO POS. AFTER FINAL LOAD WAS RECEIVED AND REVIEWED, CHKLIST COMPLETED, FO NOTIFIED TWR 'ACR XX HVY READY FOR TKOF.' TWR REPLIED 'ROGER, I'LL GET RIGHT BACK TO YOU.' SHORTLY AFTER THAT EXCHANGE, CREW HEARD TWR SAY 'ACR XX HVY, R TURN, HDG 340, CLRED FOR TKOF.' FO READ BACK CLRNC VERBATIM. CAPT SCANNED COCKPIT, ASKED IF CREW WAS READY. ON AFFIRMATIVE FROM EACH, TKOF WAS STARTED. AS ACFT PASSED INTXN OF 32R/9L, CREW OBSERVED MLG TAKING OFF ON 9L, GEAR RETRACTION ALMOST COMPLETE WHEN FIRST SIGHTED. MLG PASSED OVER AND BEHIND US WHILE WE CONTINUED TO ACCELERATE FOR NORMAL TKOF. AFTER AIRBORNE, TWR ADVISED TO TURN TO 360 AND THAT WE HAD TAKEN THE CLRNC FOR Y HVY. FO REPLIED WE HAD A CLRNC FOR ACR XX HVY AND HAD READ THAT BACK. TWR AGAIN SAID 'THE CLRNC WAS FOR Y HVY -- NO PROB.' BUT THERE WAS A PROB, AND THAT IS WHY THIS RPT IS FILED. BECAUSE WE HAD BEEN ON TWR FREQ FOR SO LONG, WE HAD NO AWARENESS OF THE OTHER ACFT WITH A SIMILAR CALL SIGN. REMAINING ON GND CTL AND OFF THE RWY UNTIL READY FOR TKOF WOULD HAVE HELPED IN THIS SIT. ALSO, A TKOF STOP/HOLD -- GO LIGHT WOULD HAVE PREVENTED THIS CONFLICT. SUPPLEMENTAL INFO FROM ACN 197454. ACR XX WHILE TAXIING TOWARDS RWY 32R AT ORD, TWR ASKED IF WE WERE READY FOR TKOF. WE HAD NOT RECEIVED OUR LOAD CLOSE OUT AND ADVISED THE TWR WE WERE NOT READY FOR TKOF. DESPITE THIS, TWR ADVISED US TO TAXI INTO POS AND HOLD. (THE CREW DISCUSSED THIS UNUSUAL SIT OF HOLDING ON A RWY WHEN NOT READY FOR DEP). THE LOAD CLOSE OUT ARRIVED, WE COMPLETED OUR CHKLISTS, AND ADVISED THE TWR WE WERE READY FOR DEP. AT THIS POINT IN TIME ORD FIELD WAS CONDUCTING SIMULTANEOUS AND INTERSECTING RWY DEPS. OUR FLT, ACR XX HVY, WAS UNAWARE OF THE ACFT ACR YXX HVY HOLDING IN POS ON RWY 32L. AFTER ADVISING THE TWR WE WERE READY FOR TKOF, TWR REPLIED, 'ACR XX HVY WILL GET RIGHT BACK TO YOU.' A SHORT TIME LATER THE FOLLOWING TKOF CLRNC WAS HEARD BY THE 4 PEOPLE IN THE COCKPIT WEARING EARPHONES. TWR: 'ACR XX HVY, TURN R HDG 340 DEG, CLRED FOR TKOF.' THE CLRNC WAS READ BACK. THE CAPT ASKED IF EVERYONE WAS READY AND WITH POSITIVE REPLIES WE PROCEEDED TO TKOF AT THE INTXN OF 32R AND RWY 9L. THE MLG PASSED OVER THE TIP OF US BY 200 FT. THE TKOF CLRNC WE RECEIVED WAS APPARENTLY FOR ACR YXX HVY. THE FOLLOWING ARE CONTRIBUTING FACTORS. SIMILAR SOUNDING CALL SIGNS. ACFT ON INTERSECTING RWYS HOLDING FOR TKOF SIMULTANEOUSLY. SPLIT TWR FREQS (WE WERE UNAWARE OF MLG DEPARTING RWY 9L). ABSENCE OF RWY ISSUED IN TKOF CLRNC. LACK OF ACTION WHEN TKOF CLRNC WAS READ BACK. THE FOLLOWING CORRECTIVE ACTIONS SHOULD BE IMPLEMENTED. DURING SIMULTANEOUS INTERSECTING RY DEPS, EXTREME CARE SHOULD BE TAKEN WITH ACFT HAVING LIKE CALL SIGNS. 2 ACFT ON INTERSECTING RWYS HOLDING FOR TKOF SHOULD BE MADE AWARE OF EACH OTHER. STOP LIGHTS, LIKE IN EUROPE, SHOULD BE CONSTRUCTED. SUPPLEMENTAL INFO FROM ACN 197459. AFTER WE WERE AIRBORNE, TWR ADVISED US THAT WE HAD TAKEN OFF ON ACR YXX HVY'S CLRNC. THE FO ANSWERED THAT HE WAS CERTAIN THAT WE HAD RECEIVED AND ACKNOWLEDGED THE CLRNC AS ACR XX HVY. TWR REPEATED THAT IT HD BEEN FOR YXX, AND ADDED, '...BUT NO PROB.' FOR A MOMENT, THAT SEEMED TO SAY THAT IT WAS ONLY A SINGLE DIGIT CLL SIGN MIX-UP ON TWR'S PART. BUT WHEN WE SWITCHED FREQS, DEP CTL ALSO ADVISED US THAT THE CLRNC HAD BEEN FOR ACR YXX HVY. LOOKING L, WE SAW ANOTHER WDB THAT HAD JUST TAKEN OFF 32L AND DECIDED THAT HE WAS YXX AND PROBABLY HE HAD, IN FACT, TAKEN OFF ON OUR CLRNC. AT NO TIMEON THE GND DO I RECALL HEARING ANY REF TO ACR YXX HVY OR THE ACFT ON RWY 4L. SUPPLEMENTAL INFO FROM ACN 197458. MLG APCHED THE RWY 4L HOLD LINE, ORD TWR CLRED 'ACFT' FOR TKOF THEN US INTO 'POS AND HOLD.' AS I WAS MAKING A SLOW R TURN TO LINE UP, TWR CLRED US FOR TKOF. I PUSHED THE THROTTLES FORWARD GAVE THE ACFT TO THE FO AND WE STARTED OUR ROLL. AT ABOUT HALF WAY DOWN THE RWY I SAW A WDB ON HIS TKOF ROLL ON 32R. I DETERMINED THAT THE SAFEST COURSE OF ACTION WOULD BE TO CONTINUE THE TKOF. WE PASSED RIGHT OVER THE TOP OF THE WDB AT ABOUT 150 FT. WHEN I QUESTIONED ORD TWR ABOUT THE INCIDENT THEY REPLIED THAT THE ACFT HAD ONLY BEEN CLRED 'POS AND HOLD.' THEY HAD MISUNDERSTOOD TKOF CLRNC FOR AN ACFT WITH A SIMILAR SOUNDING CALL SIGN, ON ANOTHER RWY. TWR PERSONNEL SHOULD KEEP THEIR EYES ON ALL ACFT THAT ARE HOLDING IN POS. ORD TWR NEVER SAID A WORD! SUPPLEMENTAL INFO FROM ACN 197554. MLG WAS CLRED INTO POS RWY 9L AT ORD. AS WE TURNED ONTO THE RWY, ORD TWR CLRED US FOR TKOF. DURING THE TKOF ROLL, THE CAPT POINTED OUT ANOTHER ACFT DEPARTING ON RWY 32R WHICH CROSSED OUR RWY. WE CONTINUED OUR TKOF BECAUSE AN ABORT WOULD HAVE CAUSED US TO STRIKE THE OTHER ACFT.

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.