NON STANDARD ATCT PHRASEOLOGY RESULTS IN ABORTED TKOF AT GRU.

Narrative

I WAS THE CAPT OF THE FLT. ALL OPS WERE NORMAL UNTIL THE TKOF. THE TKOF CLRNC WAS ISSUED USING THE FOLLOWING TERMINOLOGY; 'ACR X IS CLRED TO LINE UP AND TAKE OFF.' THE ACFT OPERATED NORMALLY DURING THE TKOF. THE TWR THEN ISSUED THE FOLLOWING CLRNC; 'ACR X; HOLD YOUR POS.' MOMENTARILY THEREAFTER; THE TWR REPEATED THE CLRNC IN A NOTICEABLY MORE URGENT TONE; 'ACR X; HOLD YOUR POS.' THE TKOF WAS ABORTED WITH A MAX SPD OBTAINED OF APPROX 125 KTS. DUE TO THE LENGTH OF THE RWY; MAX BRAKING WAS ONLY MOMENTARY AS APPLIED BY THE AUTOMATIC REJECTED TKOF FEATURE AND THE REMAINDER OF THE ROLLOUT WAS QUITE GENTLE. THE ACFT WAS BROUGHT CLR OF THE RWY. APPROPRIATE ATC AND CABIN COORD AND CHKLIST PROCS WERE ACCOMPLISHED. MAINT WAS SUMMONED AND RESPONDED RAPIDLY FOR BRAKE INSPECTION. THEY INDICATED THAT TEMPS WERE SIMILAR TO THOSE FOUND AFTER A NORMAL LNDG. SUBSEQUENTLY; THE ACFT WAS TAXIED TO A GATE. APPROPRIATE MAINT INSPECTIONS AND REFUELING WERE ACCOMPLISHED. THE FLT CONTINUED WITHOUT FURTHER EVENT. THE CTLR'S TERMINOLOGY PRESUMABLY INTENDED TO CANCEL THE TKOF CLRNC WAS NONSTANDARD. THE REPEATED CLRNC AND THE URGENCY OF THE TONE; HOWEVER; COMMUNICATED HIS MESSAGE UNMISTAKABLY. CANCELLATION OF A TKOF CLRNC SIGNIFICANTLY INTO THE TKOF ROLL IS HIGHLY UNUSUAL. THE TONE OF DELIVERY WAS ALSO UNCOMMON. THE CLR IMPLICATION WAS THAT CONTINUATION OF THE TKOF WOULD BE UNSAFE IN SOME WAY KNOWN TO THE CTLR. THIS; COUPLED WITH THE GENEROUS AMOUNT OF RWY REMAINING INDICATED AN ABORT AS THE SAFEST COURSE OF ACTION AND IN ACCORDANCE WITH ACR ABORT GUIDANCE. THE CREW WAS NOT INFORMED AS TO WHY THE TKOF CLRNC WAS CANCELED. THERE WAS AN ACFT CLRING A PARALLEL RWY AND PERHAPS THE CTLR HAD SOME CONCERNS REGARDING THAT ACFT. THIS; HOWEVER; IS JUST CREW SPECULATION. PERHAPS THE CTLR WAS AWARE OF SOME OTHER UNSAFE CONDITION AT OR NEAR THE ARPT. AT ANY RATE; THE CREW WAS NOT INFORMED.