FLC OF MLG ON DSCNT UNABLE TO MAKE XING RESTRICTION ACCOUNT LATE DSCNT. MISCOMPUTED XING POINT AND LOSS OF RADIO COM WITH CENTER.

Narrative

APCHING MEM ON THE EALET 5 ARR; CENTER ISSUED A CLRNC TO CROSS 85 MI SW OF MEM AT 240. CAPT CALCULATED THAT POINT TO BE 24 MI SW OF SEABO ON THE ARR AND ENTERED THAT INTO THE FMS. I CONCURRED WITH THAT POINT. ABOUT THIS TIME THE CAPT PLACED A BOX OF DOUGHNUTS ONTO THE CENTER CONSOLE. THE BOX APPARENTLY CAUSED THE #1 COM RADIO TO CHANGE FREQS BY 1 DIGIT; ALTHOUGH WE DID NOT KNOW IT AT THE TIME. ALSO AT THIS TIME; A FLT ATTENDANT CAME TO THE COCKPIT TO CLAIM A DOUGHNUT. APPROX 100 MI FROM MEM WE BOTH NOTICED THAT THE FMS TOP OF DSCNT POINT SEEMED TOO CLOSE TO THE XING POINT; AND A DSNT WAS INITIATED. IT WAS THEN DISCOVERED THAT THE FL240 RESTRICTION HAD BEEN INCORRECTLY ENTERED INTO THE FMS AT THE NEXT POINT BEYOND THE PROPER XING POINT. THIS MAY BE DUE TO PUSHING THE BUTTON NEXT TO THE WRONG POINT OR THE FMS MAY HAVE SWITCHED TO THE NEXT POINT JUST AS THE ALT RESTRICTION BUTTON WAS PRESSED. WHEN I TRIED TO CALL CENTER TO TELL THEM WE WOULD NOT MAKE THE ALT RESTRICTION; I DISCOVERED WE WERE NOT IN CONTACT. I CALLED THE PREVIOUS FREQ TO GET THE CORRECT FREQ. WHEN I CHKED IN WITH CENTER THEY SAID THEY HAD BEEN TRYING TO CONTACT US. THE CTLR ASSIGNED A LOWER ALT AS WE PASSED OVER THE ALT XING POINT (85 DME MEM) ABOUT 3500 FT HIGH.