CARJ CREW EXCEEDED THE CONFINES OF THE ASSIGNED HOLDING PATTERN.

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A WHILE AGO; A MEMO WAS CIRCULATED WARNING THAT IF THE '1/2 BANK' MODE ON THE FLT DIRECTOR/AUTOPLT WAS ENGAGED/SELECTED AT THE SAME TIME THAT A HOLDING PATTERN WAS PROGRAMMED INTO THE FMS; THEN THE RESULTING HOLDING PATTERN WOULD BE OVERLY WIDE AND WOULD LIKELY TAKE THE ACFT BEYOND THE STANDARD AIRSPACE BOUNDARIES FOR THE HOLD. DURING OUR FLT; ATC ISSUED A HOLD OVER THE APE VOR. I WAS ON COM #2 AT THE TIME ATTEMPTING TO CONTACT DISPATCH WHEN THE CAPT RECEIVED THE HOLDING CLRNC ON COM #1 AND PROGRAMMED THE FMS. WHEN I FINISHED WITH DISPATCH THE CAPT BRIEFED ME ON THE ASSIGNED HOLD AND WE VERIFIED THAT THE FMS WAS PROGRAMMED CORRECTLY. ABOUT THAT TIME; WE APCHED THE HOLD ENTRY POINT AND THE PICTURE OF THE HOLD ON THE MFDU BLOSSOMED TO ABOUT TWICE ITS PREVIOUS WIDTH. THE FIRST THING I DID WAS VERIFY THAT THE '1/2 BANK' WAS OFF; WHICH IT WAS. HOWEVER; THE 'TURB' MODE WAS ENGAGED AND IT WAS MUCH THE SAME EFFECT AS THE 1/2 BANK MODE BY LIMITING THE RATE AT WHICH THE AUTOPLT ENTERS A BANK AND; APPARENTLY; THE AMOUNT OF BANK THE AUTOPLT WILL USE. I TOLD THE CAPT IMMEDIATELY ABOUT ALL OF THE ABOVE AND MADE IT KNOWN THAT I BELIEVED THE HOLDING PATTERN WAS MUCH TOO WIDE. HOWEVER; HE FELT THAT ALL WAS WELL WITH THE HOLD AND WOULD NOT REPROGRAM THE FMS. AS WE COMPLETED THE ENTRY AND BECAME ESTABLISHED ON THE OUTBOUND LEG ATC VECTORED US BACK TOWARD THE APE VOR AND THE INBOUND COURSE. SHORTLY THEREAFTER WE WERE CLRED TO PROCEED ON COURSE TO ANOTHER FIX. IN THE FUTURE; I WILL ENSURE THAT BOTH THE '1/2 BANK' AND 'TURB' MODES ARE OFF WHENEVER A HOLD IS BEING PROGRAMMED/ENTERED/FLOWN.