GA SMA CAUSES A GND CONFLICT THAT FORCES AN ACR TO GAR FROM SHORT FINAL AT ATL RWY 26R.

Narrative

WHILE AT HARTSFIELD; ATLANTA (ATL) OUR TAXI CLRNC FROM THE GA RAMP WAS TO TAXI TO 27R; HOLD SHORT OF 26R AT DELTA/DIXIE. UPON REACHING DELTA; WE WERE CLRED TO IMMEDIATELY CROSS 26R. AN AIRLINES FLT WAS ON SHORT FINAL. WE ACCELERATED PROMPTLY TO CROSS 26R; HOWEVER OUR CLRNC DID NOT SPECIFY WHETHER OR NOT TO CROSS 26L. RATHER THAN CROSS THAT RWY ILLEGALLY; I CHOSE TO CLARIFY THE CLRNC WITH GND CTL. APPARENTLY; GND HAD CLRED ANOTHER ACFT TO CROSS BOTH RWYS THAT WAS BEHIND US. DUE TO THIS; AND OUR STOPPING TO CLARIFY THE CLRNC FOR THE PARALLEL RWY; THE ACFT ON FINAL WAS FORCED TO GAR. THE FACTORS CONTRIBUTING TO THIS INCIDENT IN MY BELIEF ARE AS FOLLOWS: FAILURE OF THE CTLR TO CLR US ACROSS BOTH RWYS; AS APPARENTLY IS THE USUAL CASE. DUE TO LACK OF FAMILIARITY WITH THE PROC AND THE ARPT; OUR DECISION NOT TO QUESTION THE CLRNC UNTIL ALREADY ACROSS THE ONE RWY. ATC CLRING 2 ACFT ACROSS AN ACTIVE RWY; WITH THE LEAD ACFT AN SMA AND THE TRAILING ACFT AN LTT. LACK OF RECOGNITION BY BOTH PLT AND CTLR OF THE AMOUNT OF TIME REQUIRED TO SAFELY TRANSIT THE 2 RWYS IN A LIGHT SINGLE ENG ACFT. THE TOTAL DISTANCE TO CLR BOTH RWYS FROM OUR ORIGINAL POS WAS NEARLY 1/4 MI. PLT'S FAILURE TO EMPHASIZE THAT THEY WERE UNFAMILIAR WITH THE ARPT/ARPT PROCS. THE COINCIDENCE THAT AT LEAST 3 ACFT WERE EXITING THE GA RAMP AT THE SAME TIME.