FLC OF MLG FAILED TO MAKE ALT XING RESTRICTION.

Narrative

ENRTE FROM DFW TO MEM; LEVEL AT FL330. WE WERE NE OF TXK ON TEXARKANA TRANSITION OF WALET 5 ARR TO KMEM; WHEN FLT ATTENDANT ENTERED COCKPIT TO BRING DRINKS AND VISIT. ABOUT THAT TIME WE WERE ISSUED A CLRNC TO CROSS 85 MI S OF MEM AT FL240. I HAD TO CONSTRUCT A WAYPOINT ON THE FMS TO CORRESPOND TO THE 85 DEG FIX OFF MEM. THIS POINT WAS SEABO INTXN MINUS 24 MI (SEABO/-24). WHEN ENTERING THE XING ALT IN THE FMS; I ACCIDENTLY PLACED IT WITH THE SEABO INTXN; MAKING THE FMS PROFILE INCORRECT. 1) FLT ATTENDANT WAS STILL IN COCKPIT AND I WAS DISTRACTED BY CONVERSATION. I HAD BROUGHT DONUTS TO SHARE WITH THE CREW AND OFFERED 1 TO THE FLT ATTENDANT; PUTTING THE BOX DOWN ON THE PEDESTAL; ON TOP OF THE RADIOS. WHEN I DID THIS I CHANNELED THE COM RADIO AND LOST COM WITH CENTER. 2) BECAUSE OF CONVERSATION WITH THE FLT ATTENDANT I DID NOT CATCH THE INCORRECT DSCNT PROFILE ON FMS AND FAILED TO XCHK RAW DATA DME UNTIL WE WERE APPROX 100 MI FROM MEM (15 MI TO DSND 9000 FT). 3) WHEN I RECOGNIZED LATE START OF DSCNT; I INITIATED A MAX RATE DSCNT WITH SPOILERS. WHEN WE TRIED TO CALL CENTER TO ADVISE THAT WE COULDN'T MAKE THE XING RESTRICTION WE DISCOVERED THE COM PROBLEM AND REESTABLISHED COM WITH CENTER. HE ADVISED US HE HAD BEEN TRYING TO CALL SEVERAL TIMES. WHEN WE TOLD HIM WE COULDN'T MAKE THE XING RESTRICTION HE DID NOT RESPOND; BUT SUBSEQUENTLY ISSUED A CLRNC TO A LOWER ALT. I DO NOT RECALL WHETHER WE HAD PASSED THE MEM/85 DEG BEFORE OR AFTER THE FURTHER DSCNT CLRNC WAS ISSUED; BUT WE WERE PASSING ABOUT FL270-FL280 (MISSING RESTRICTION BY 3000- 4000 FT). THE CTLR DID NOT INDICATE THAT THERE WAS ANY CONFLICT; BUT I CLRLY HAD NOT COMPLIED WITH THE XING RESTRICTION IF IT WAS STILL PART OF MY CLRNC. THIS WAS SOME VERY SLOPPY; UNPROFESSIONAL FLYING ON MY PART! THE COMBINATION OF FAILING TO MAKE A XING RESTRICTION WITH A LOSS OF COM COULD EASILY HAVE RESULTED IN MORE THAN JUST MY EMBARRASSMENT. MORE ATTN TO RAW DATA AND LESS SOCIALIZING WOULD HAVE GONE A LONG WAY IN PREVENTING THIS INCIDENT.