Narrative:

We departed the gate and we were instructed to taxi to runway 21R via the blue-8 taxi route. While we were on taxiway pp and approaching the intersection with taxiway F, we were told to stop. There was an rj that stopped short of the high speed taxiway, and was clearing runway 21L on taxiway F. I assumed that we would allow the rj to proceed by us on taxiway F, and then we would continue to runway 21R via the blue-8. Well, we were issued new taxi instructions at this time. We were told to taxi to runway 21R via taxiway F. We weren't instructed to hold short of runway 21R. As we approached runway 21R, we received in quick succession several ACARS messages. The first message title read, 'you are illegal.' this got our attention, as we couldn't understand what was up. The first officer pulled up this message to see what was going on. We then received another, and then another ACARS message. In total, we received about 4 messages from the time we turned onto taxiway F. As we approached the hold short line, we heard ground control telling us to stop. His words were something to the effect of, 'air carrier X, stop.' we instantly stopped, and quickly looked to our right and noticed a crj taking off. We definitely weren't on the runway, but we may have been over the hold short line. Ground then cleared us to taxi to runway 21R via taxiway F, runway 9L and taxiway M to runway 21R. I do not recall receiving a hold short clearance, and my first officer was positive that we were cleared to cross runway 21R at taxiway F. The problem seems to be a miscom between us and ground control. We understood that we were cleared to cross runway 21R. Getting several ACARS messages at this time also led to some confusion. I recall asking him to read the first message titled, 'you are illegal,' as this isn't a normal message. He was heads down as we approached the runway reading the different messages, and relaying the information to me. Part of the first 'you are illegal' message stated that we should remain at the gate. We didn't understand this, as we blocked out over 5 mins earlier. Supplemental information from acn 617908: suddenly we began to receive multiple ACARS messages. I went heads down to read the messages. I also observed an aircraft just rotating and climbing out from the same runway. The departing act passed us at an altitude of about 50 ft.

Related reports:

Google
 

Original NASA ASRS Text

Title: RWY INCURSION BY A DC9 FLT CREW WHEN CLRED TO TAXI TO RWY 21R FROM INTXN F AND INTXN PP AT DTW, MI.

Narrative: WE DEPARTED THE GATE AND WE WERE INSTRUCTED TO TAXI TO RWY 21R VIA THE BLUE-8 TAXI RTE. WHILE WE WERE ON TXWY PP AND APCHING THE INTXN WITH TXWY F, WE WERE TOLD TO STOP. THERE WAS AN RJ THAT STOPPED SHORT OF THE HIGH SPD TXWY, AND WAS CLRING RWY 21L ON TXWY F. I ASSUMED THAT WE WOULD ALLOW THE RJ TO PROCEED BY US ON TXWY F, AND THEN WE WOULD CONTINUE TO RWY 21R VIA THE BLUE-8. WELL, WE WERE ISSUED NEW TAXI INSTRUCTIONS AT THIS TIME. WE WERE TOLD TO TAXI TO RWY 21R VIA TXWY F. WE WEREN'T INSTRUCTED TO HOLD SHORT OF RWY 21R. AS WE APCHED RWY 21R, WE RECEIVED IN QUICK SUCCESSION SEVERAL ACARS MESSAGES. THE FIRST MESSAGE TITLE READ, 'YOU ARE ILLEGAL.' THIS GOT OUR ATTN, AS WE COULDN'T UNDERSTAND WHAT WAS UP. THE FO PULLED UP THIS MESSAGE TO SEE WHAT WAS GOING ON. WE THEN RECEIVED ANOTHER, AND THEN ANOTHER ACARS MESSAGE. IN TOTAL, WE RECEIVED ABOUT 4 MESSAGES FROM THE TIME WE TURNED ONTO TXWY F. AS WE APCHED THE HOLD SHORT LINE, WE HEARD GND CTL TELLING US TO STOP. HIS WORDS WERE SOMETHING TO THE EFFECT OF, 'ACR X, STOP.' WE INSTANTLY STOPPED, AND QUICKLY LOOKED TO OUR R AND NOTICED A CRJ TAKING OFF. WE DEFINITELY WEREN'T ON THE RWY, BUT WE MAY HAVE BEEN OVER THE HOLD SHORT LINE. GND THEN CLRED US TO TAXI TO RWY 21R VIA TXWY F, RWY 9L AND TXWY M TO RWY 21R. I DO NOT RECALL RECEIVING A HOLD SHORT CLRNC, AND MY FO WAS POSITIVE THAT WE WERE CLRED TO CROSS RWY 21R AT TXWY F. THE PROB SEEMS TO BE A MISCOM BTWN US AND GND CTL. WE UNDERSTOOD THAT WE WERE CLRED TO CROSS RWY 21R. GETTING SEVERAL ACARS MESSAGES AT THIS TIME ALSO LED TO SOME CONFUSION. I RECALL ASKING HIM TO READ THE FIRST MESSAGE TITLED, 'YOU ARE ILLEGAL,' AS THIS ISN'T A NORMAL MESSAGE. HE WAS HEADS DOWN AS WE APCHED THE RWY READING THE DIFFERENT MESSAGES, AND RELAYING THE INFO TO ME. PART OF THE FIRST 'YOU ARE ILLEGAL' MESSAGE STATED THAT WE SHOULD REMAIN AT THE GATE. WE DIDN'T UNDERSTAND THIS, AS WE BLOCKED OUT OVER 5 MINS EARLIER. SUPPLEMENTAL INFO FROM ACN 617908: SUDDENLY WE BEGAN TO RECEIVE MULTIPLE ACARS MESSAGES. I WENT HEADS DOWN TO READ THE MESSAGES. I ALSO OBSERVED AN ACFT JUST ROTATING AND CLBING OUT FROM THE SAME RWY. THE DEPARTING ACT PASSED US AT AN ALT OF ABOUT 50 FT.

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.