Narrative:

On taxiway west approaching runway 4L at ord, tower cleared an air carrier Y on taxiway east to take off on runway 4L ahead of us. We were then instructed to 'keep it moving and stay as closed as you can behind air carrier Y, you are going right out.' unsure of whether he wanted us to cross the hold line, we waited for a 'taxi into position and hold,' which came with air carrier Y not having released brakes yet. While still moving up on the taxiway, we received a 'cleared for takeoff, turn 090 degrees' clearance. We declined the clearance stating 'we are not going to release brakes until air carrier Y lifts off.' air carrier Y rolled another 2000-3000 ft before his nose gear lifted off. All the while tower was pressuring us to roll due to landing traffic on runway 9L. I established visual contact with the traffic approaching on runway 9L. I decided it was less hazardous to roll through the intersection of runways 4L and 9L than to stay so near the cross runway in my present position. We released brakes and took off normally as soon as air carrier Y ahead of us lifted off. Upon further reflection, 2 troubling safety issues stand out. 1) an ord tower controller issued an unsafe takeoff clearance with the preceding aircraft still well below V1 and only 1/2 way through his takeoff roll. 2) clearance to take off was given with an aircraft dangerously close to landing on a cross runway. Had we delayed our takeoff just 10-15 seconds or had we performed a low speed abort, the traffic about to land would have needed to perform a go around at very low altitude to prevent a catastrophic collision.

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Original NASA ASRS Text

Title: ACR PLT DEPARTING ORD WAS CONCERNED WHEN A CLRNC FOR TKOF WAS GIVEN BEFORE THE PRECEDING ACFT HAD LIFTED OFF.

Narrative: ON TXWY W APCHING RWY 4L AT ORD, TWR CLRED AN ACR Y ON TXWY E TO TAKE OFF ON RWY 4L AHEAD OF US. WE WERE THEN INSTRUCTED TO 'KEEP IT MOVING AND STAY AS CLOSED AS YOU CAN BEHIND ACR Y, YOU ARE GOING RIGHT OUT.' UNSURE OF WHETHER HE WANTED US TO CROSS THE HOLD LINE, WE WAITED FOR A 'TAXI INTO POS AND HOLD,' WHICH CAME WITH ACR Y NOT HAVING RELEASED BRAKES YET. WHILE STILL MOVING UP ON THE TXWY, WE RECEIVED A 'CLRED FOR TKOF, TURN 090 DEGS' CLRNC. WE DECLINED THE CLRNC STATING 'WE ARE NOT GOING TO RELEASE BRAKES UNTIL ACR Y LIFTS OFF.' ACR Y ROLLED ANOTHER 2000-3000 FT BEFORE HIS NOSE GEAR LIFTED OFF. ALL THE WHILE TWR WAS PRESSURING US TO ROLL DUE TO LNDG TFC ON RWY 9L. I ESTABLISHED VISUAL CONTACT WITH THE TFC APCHING ON RWY 9L. I DECIDED IT WAS LESS HAZARDOUS TO ROLL THROUGH THE INTXN OF RWYS 4L AND 9L THAN TO STAY SO NEAR THE CROSS RWY IN MY PRESENT POS. WE RELEASED BRAKES AND TOOK OFF NORMALLY AS SOON AS ACR Y AHEAD OF US LIFTED OFF. UPON FURTHER REFLECTION, 2 TROUBLING SAFETY ISSUES STAND OUT. 1) AN ORD TWR CTLR ISSUED AN UNSAFE TKOF CLRNC WITH THE PRECEDING ACFT STILL WELL BELOW V1 AND ONLY 1/2 WAY THROUGH HIS TKOF ROLL. 2) CLRNC TO TAKE OFF WAS GIVEN WITH AN ACFT DANGEROUSLY CLOSE TO LNDG ON A CROSS RWY. HAD WE DELAYED OUR TKOF JUST 10-15 SECONDS OR HAD WE PERFORMED A LOW SPD ABORT, THE TFC ABOUT TO LAND WOULD HAVE NEEDED TO PERFORM A GAR AT VERY LOW ALT TO PREVENT A CATASTROPHIC COLLISION.

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.