LCL CTLR AT MSP USED INCORRECT CALL SIGN AND CAUSED 2 ACFT IN POS ON XING RWYS TO DEPART AT THE SAME TIME.

Narrative

MSP INTL WAS DEPARTING AND ARRIVING RWY 30L AND RWY 30R WITH INTERSECTING DEPS RWY 22 AT TXWY M-7. WX WAS OVCST WITH TSTMS AND RAINSHOWERS IN THE VICINITY. TFC WAS CONGESTED DUE TO THE WX; THE HR OF THE DAY; AND THE FACT A RWY CHANGE HAD JUST OCCURRED. IT REQUIRED US NEARLY 40 MINS OF TAXI TO REACH THE RWY. TWR CLRED US INTO POS AND HOLD RWY 22 AT TXWY M7; AND WE DID SO. I SET THE PARKING BRAKE AND BEGAN ANALYZING THE RADAR RETURNS FROM RAINSHOWERS WITHIN ABOUT 10 NM OF THE RWY CTRLINE EXTENDING SW. WE (THE FO AND I) DISCUSSED BRIEFLY GETTING A 180 DEG HDG OR DEP AS THE PRECEDING 2 ACFT FROM RWY 22 HAD DONE TO AVOID THE WX. WE THEN RECEIVED A TKOF CLRNC USING OUR CALL SIGN TO MAINTAIN RWY HDG; CLRED FOR TKOF. I HAD KEYED MY ATTN TO THE CALL SIGN AND 'RWY HDG;' AS WE HAD DISCUSSED THE 180 DEG HDG (ABOUT 40 DEGS L) FOR AN INITIAL HDG. INSTEAD OF QUESTIONING THE HDG; THE FO RESPONDED TO THE CLRNC. I DECIDED WE HAD ENOUGH ROOM TO GET THE HDG AFTER WE WERE AIRBORNE; AND SO RELEASED THE BRAKES AND DEPARTED. WE GOT THE HDGS WE NEEDED FROM DEP CTL; AND THE REMAINDER OF THE FLT WAS UNEVENTFUL. THE NEXT DAY; I WAS CONTACTED BY THE COMPANY THAT MSP TWR WAS FILING A PLT DEV FOR DEPARTING WITHOUT A CLRNC. IT TURNS OUT THEY HAD AN ACFT HOLDING IN POS RWY 30L AT THE SAME TIME AS US ON RWY 22 AT TXWY M7. TWR HAD MISTAKENLY STATED OUR CALL SIGN IN THE CLRNC; 'RWY 30 L; FLY RWY HDG; CLRED FOR TKOF;' INTENDING TO CLR THE OTHER ACFT FOR TKOF. BOTH THE OTHER ACFT HOLDING AND WE RESPONDED TO THE CLRNC AND DEPARTED. WE COULD NOT SEE THE OTHER ACFT HOLDING FROM OUR POS WHILE HOLDING; NOR DID WE ON TKOF; BUT WE ESTIMATE WE CROSSED THE INTXN APPROX 3000 FT AHEAD OF THEM. TWR REALIZED WHAT WAS OCCURRING; DETERMINED WE HAD THE OTHER ACFT BEAT THROUGH THE INTXN; AND WISELY DECIDED NOT TO CALL AN ABORT AS WE MAY HAVE STOPPED IN THE INTXN. NO OTHER XMISSIONS WERE MADE EXCEPT TO CALL DEP. I BELIEVE THIS RWY SETUP IS A TEXTBOOK CASE FOR POOR DESIGN AND IMPLEMENTATION; ESPECIALLY AS IT IS USED ONLY WHEN THE RADIOS AND TFC ARE MOST CONGESTED. NOT BEING ABLE TO SEE OTHER ACFT HOLDING ON THE INTERSECTING RWY IS ALSO AN INHERENT PROB. FROM OUR PERSPECTIVE; BY THE TIME A CREW IS IN POS FOR TKOF AND HOLD; WE HAVE PROCEEDED IN DELIBERATE; MEASURED STEPS TO THIS POINT. WE HAVE COMPLETED ALL THE CHKS REQUIRED TO TKOF. WE HAVE A DEP PLAN RELATIVE TO WX; MECHANICAL MALFUNCTIONS; AND SIDS; AND ARE PREPARED TO EXECUTE IT. THIS IS A POINT WHEN THE ANTICIPATION CAN ALLOW YOU TO THINK YOU HEARD WHAT YOU EXPECTED TO HEAR.