AN AIR CARRIER CREW DESCRIBES A POSITION AND HOLD CLEARANCE CANCELLATION AND THE CONFUSION THAT OCCURRED WHEN MULTIPLE ATC CLEARANCES WERE MIXED WITH MULTIPLE RAAS ALERTS.

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WE WERE #2 BEHIND ACR X SHORT OF RWY XX. TWR ADVISED US AND ACR X BE READY FOR IMMEDIATE TKOFS. ACR X WAS CLRED FOR TKOF. THIS IS THE RADIO AND CREW COM AS BEST I COULD REMEMBER THEM. ZZZ TWR: ACR Y POS AND HOLD RWY BE READY FOR AN 'UNKNOWN.' RAAS: APCHING RWY XX. ZZZ TWR: ACR Y CANCEL TKOF CLRNC IMMEDIATELY CLR RWY XX 'UNKNOWN.' RAAS: ON RWY XX. ZZZ TWR: ACR Y CLR XX ON C1 DO A 180 AND HOLD SHORT OF RWY XX. ACR Y: WILCO; CLR XY. 180 ON C1; HOLD SHORT OF XX; AGAIN. RAAS: APCHING RWY XX. ZZZ TWR: ACR Y POS AND HOLD XX. ACR Y: POS AND HOLD ZZ. ZZZ TWR: LNDG ACFT CLR RWY ASAP. ZZZ TWR: ACR Y CLRED FOR 'UNKNOWN.' RAAS: ON RWY XX. ACR Y CREW: DID HE CLR US FOR TKOF? ACR Y: TWR SAY AGAIN FOR ACR Y. ZZZ TWR: ACR Y CLR FOR AN IMMEDIATE TKOF ON RWY XX. AS YOU CAN SEE WE HAD 4 DIFFERENT RAAS EVENTS HAPPEN TO US WITHIN ABOUT A 1:30 TIME FRAME WHEN ATC AND CREW COMS WERE OF THE UTMOST IMPORTANCE. AS A SIDE NOTE; LATER ON IN THE FLT WE CAUGHT AND MITIGATED SEVERAL OTHER MINOR EVENTS THAT ORDINARILY WE WOULD NOT HAVE HAD TO; BECAUSE AT THE TIME; ONE OR BOTH OF US WAS STILL THINKING ABOUT THE EVENTS THAT TOOK PLACE WITH THE EARLIER RAAS EVENT. 1) I'M NEITHER IN FAVOR OR OPPOSED TO RAAS. 2) I THINK IT HAS THE ABILITY TO EITHER SAVE A CREW AND ITS PAX OR POTENTIALLY BE THE ROOT CAUSE OF A SERIOUS ACCIDENT FOR A CREW AND ITS PAX IN ITS CURRENT FORM. 3) ON/OFF SWITCH! ZZZ SINGLE RWY; VMC; DO I REALLY NEED RAAS? ZZZ1 1/4 VISIBILITY DO I REALLY NEED RAAS? YOU CAN SEE HOW THIS WOULD LEAVE THE CREW WITH THE DISCRETION TO USE IT WHEN THE CREW FELT IT WAS NEEDED. 4) RAAS IS GOING TO TAKE TIME. AT THE VERY LEAST THE CREW HAS TO HAVE THE ABILITY TO TURN IT ON OR OFF. IF THIS IS NOT AN OPTION; THEN I STRONGLY FEEL THAT RAAS SHOULD BE TAKEN OFF THE ACFT IMMEDIATELY. IT IS AN ACCIDENT WAITING TO HAPPEN! SUPPLEMENTAL INFO FROM ACN 811694: THE POTENTIAL FOR RAAS TO INTERFERE WITH TIME-CRITICAL COMS WITH TWR IS FAR TOO HIGH TO SAFELY ACCEPT SUCH A CLRNC. AS A PLT: 1) I WILL NOT ACCEPT A 'BE READY FOR IMMEDIATE TKOF' CLRNC ON AN RAAS EQUIPPED ACFT. 2) TO MITIGATE THE RAAS HAZARD ON A STANDARD POS AND HOLD CLRNC; I WILL HOLD IN POS 30 DEGS OFF THE RWY AXIS; TO PREVENT RAAS FROM INTERFERING WITH OUR TKOF CLRNC. NOTE THAT AFTER THAT I WILL HAVE TO ALIGN THE ACFT WITH THE RWY TO TAKE OFF; RAAS WILL BLARE; AND THEN HAS THE POTENTIAL TO COVER A 'CANCEL TKOF CLRNC' CALL FROM TWR. 3) SHOULD MEASURE 2 PROVE INADEQUATE; I MAY NEED TO REFUSE ALL POS AND HOLD CLRNCS ON RAAS EQUIPPED ACFT. FOR THE RAAS ITSELF: 1) IMMEDIATELY REMOVE THE SYS FROM OUR ACFT BEFORE IT CAUSES AN ACCIDENT. 2) REINSTALL THE SYS ONLY IF IT HAS AN ON/OFF SWITCH; DEFAULTED TO OFF; SO THE FLT CREW CAN DETERMINE; BASED ON THEIR PROFESSIONAL JUDGEMENT OF THE FLT CONDITIONS; WHETHER THE HAZARDS OF RAAS-CAUSED INTERFERENCE WITH COMS ARE WORTH ANY POTENTIAL BENEFITS.