B737-300 FLT CREW HAS TRACK DEV ATTEMPTING TO ENTER HOLD DEFINED BY A DISTANCE FROM AN RNAV WAYPOINT.

Narrative

UPON ARRIVING IN THE MDW TERMINAL AREA; ATC INFORMED US TO PLAN FOR A HOLDING PATTERN DUE TO TFC SATURATION IN THE CHICAGO AREA. WE WERE CLRED TO THE FISSK INTXN TO HOLD AS PUBLISHED EXCEPT L TURNS. WE ENTERED THIS HOLD SUCCESSFULLY AND ONCE ESTABLISHED; I (AS THE PLT MONITORING) BEGAN COMMUNICATING WITH OUR DISPATCHER VIA ACARS TO CHANGE OUR FLT PLANNED ALTERNATE TO IND SO WE COULD HAVE MORE HOLDING TIME TO GET INTO MDW. DISPATCH AGREED WITH THIS CHANGE. ATC REVISED OUR EFC. AFTER A COUPLE OF TURNS IN THE HOLD; ATC RELEASED US FROM THE HOLD DIRECT TO HALIE INTXN TO PLAN FOR A POSSIBLE HOLD CLOSER TO THE ARPT. WE ENTERED HALIE INTXN IN THE CDU AND WENT LNAV DIRECT TO HALIE. ON THE WAY TO HALIE; WE HAD TO DEVIATE FOR TSTMS. ATC THEN GAVE US THIS CLRNC: HOLD ON THE HALIE 090 DEG RADIAL 10 DME FIX; R TURNS; 10 DME LEGS. WHAT WE ENTERED IN THE HOLD PAGE OF THE CDU WAS EVERYTHING BUT THE 10 DME POINT E OF HALIE. WHAT WE SHOULD HAVE DONE WAS BUILD THE NEW HOLDING POINT E OF HALIE; GONE DIRECT TO THAT POINT AND THEN PROGRAMMED THE CORRECT HOLD IN THE CDU HOLD PAGE. WE FLEW TO HALIE AND ENTERED A HOLD E OF HALIE ON THE 090 DEG RADIAL R TURNS WITH 10 DME LEGS. ATC THEN INFORMED US THAT THEY WANTED US 10 MI E OF THAT POS. WE REPROGRAMMED THE CDU FOR THE NEW POINT AND FLEW DIRECT TO THAT POINT AND RE-ENTERED THE CORRECT HOLD. THIS IS THE FIRST TIME THAT I HAD TO HOLD ON AN RNAV ARR AND I FOUND IT DIFFICULT TO KEEP THE BIG PICTURE OF WHERE WE WERE HOLDING DUE TO THE FACT THAT WE WERE IN A -300 WITH NO VISUAL DISPLAY OF THE FLT PATH. I WAS USING RAW DATA OFF OF CGT VOR TO AT LEAST VERIFY THAT WE WERE ON THE 090 DEG RADIAL AND THEN GOING BACK TO THE NAV MODE TO FLY THE HOLD. AFTER A FEW TURNS IN THE NEW HOLD; ATC RELEASED US TO CHICAGO APCH; AND AFTER SOME MORE DEVIATING AROUND WX; WE LANDED AT MDW. ONE OTHER POINT IS THAT WITH ONLY 1 CDU IN THE -300 IT WAS DIFFICULT DIVIDING OUR TIME BTWN TALKING TO DISPATCH VIA ACARS AND NAVING VIA LNAV.