FLC RUSHED; TAXI INSTRUCTIONS CHANGED BY GND CTL; FO OUT OF AWARENESS LOOP DURING CHKLIST AND ACFT INTRUDED ON RWY CAUSING ACFT ON APCH TO GAR.

Narrative

I WAS MONITORING GND CTL FREQ WHEN WE WERE INSTRUCTED TO TAXI TO RWY 4R VIA TXWY A-E-S; HOLD SHORT OF RWY 4L. IMMEDIATELY AFTER RECEIVING OUR TAXI INSTRUCTIONS THE GND CTL FREQ BECAME VERY CONGESTED. THE CTLR WAS HAVING SOME DIFFICULTY WITH OTHER AIRPLANES AND THEIR TAXI CLRNCS (IT SEEMS THE OTHER ACFT WERE NOT SURE WHICH RWY TO TAXI TO AND WHICH TAXI RTE TO FOLLOW). WHILE THIS WAS HAPPENING; THE CTLR CHANGED OUR TAXI INSTRUCTIONS TO RWY 9; VIA TXWY A-K-W-S; HOLD SHORT OF RWY 4L. WE WERE ENRTE FROM OUR ORIGINAL TAXI POINT; KNOWN AS 'THE OLD FIRE STATION;' WHEN WE RECEIVED THE NEW TAXI INSTRUCTIONS. I READ BACK THE NEW TAXI INSTRUCTIONS AND MY CAPT WHO WAS TAXIING THE ACFT CHKED THE NEW TAXI INSTRUCTIONS ON HIS CHART. I WAS PERFORMING MY TAXI FLOWS TO XCHK THEM WITH THE CHKLIST; AN INVOLVED LENGTHY PROC; WHEN I FELT THE CAPT MAKE A SUDDEN STOP. SHORTLY AFTER THIS; GND CTL WAS CONTACTING US AGITATEDLY ASKING US TO HOLD SHORT OF RWY 4L. WHEN I LOOKED AWAY FROM MY CHKLIST I NOTICED THAT OUR ACFT WAS APPROX 20 FT FROM THE RWY SIDE LINE. ALTHOUGH OUR ACFT HAD CROSSED THE HOLD SHORT LINE; WE WERE STILL CLR FROM RWY 4L IN FRONT OF US. I NOTICED THE INTXN NEXT TO US AND BEHIND US WERE CONGESTED WITH ACFT AND A LNDG ACFT GOING AROUND. THERE WAS NEVER A RWY INCURSION SINCE WE HAD PLENTY OF ROOM TO MAKE A 180 DEG TURN AND STILL REMAIN CLR OF THE RWY AS INSTRUCTED BY GND CTL. WE RECEIVED A THIRD TAXI CLRNC AND EVENTUALLY WERE CLRED FOR TKOF. UPON CLRNC FOR TKOF; SINCE IT WAS MY LEG; I ASSUMED THE CTLS. DURING OUR CLBOUT WE EXPERIENCED RADIO LOSS FOR A BRIEF MOMENT WHILE SWITCHING FREQ. DURING THE HDOF FROM TWR TO DEP; MY CAPT TRIED SEVERAL TIMES TO ESTABLISH CONTACT WITH DEP; AND AFTER A FEW ATTEMPTS HE RETURNED BACK TO THE TWR TO NOTIFY THEM OF OUR MALFUNCTION AND WE WERE GIVEN ANOTHER FREQ. SOON AFTER THIS; ALL SYS OPERATED NORMALLY. I BELIEVE THAT THE UNUSUALLY COLD TEMP IN WHICH THE ACFT WAS EXPOSED TO THROUGH THE NIGHT; AND OUR BEING THE FIRST FLT OF THE DAY; MAY HAVE BEEN A CONTRIBUTING FACTOR TO THIS BRIEF RADIO GLITCH; AS FOR THE INCIDENT ON THE GND; IT MAY WELL HAVE BEEN A BREAKDOWN IN COM BTWN US AND GND CTL; COMBINED WITH A HVY WORKLOAD IN A LIMITED AMOUNT OF TIME.