MISSED CROSSING RESTRICTION BY 4000'.

Narrative

ENRTE TO DCA FROM SAVANNAH WE WERE ISSUED THE XING RESTRICTION OF FL270; 80 S OF RIC VOR ON J52. AS I RECALL IT WAS NOT A CLRNC THAT REQUIRED A RAPID DSCNT. DURING THE DSCNT I WAS BUSY WITH NORMAL COPLT FUNCTIONS; EG; CHKLISTS; ATIS; FREQ CHANGES AND MONITORING FOR TRACKING; MY OTHER CONCERN WAS THE BASIC AIRMANSHIP OF THE CAPT AS HE WAS A BIT RUSTY. AS IT TURNS OUT; I WAS TOO; AS WE MISSED OUR RESTRICTION BY NEARLY 4000'. AFTER BEING QUESTIONED BY THE NEXT CTLR; I RESPONDED THAT 'YES; WE HAD A RESTRICTION AND WOULD DSND RAPIDLY.' NO FURTHER COMMENTS WERE MADE. THE REAL PROB CONCERNS A CAPT WHOSE ENTIRE THOUGHT PROCESS WAS NOT DEDICATED TO A PARTICULAR FLT THUS REQUIRING ANY COPLT TO DO 2 JOBS-HIS AND THE CAPT'S. SAFETY IS NOT COMPROMISED AS THE BASIC SKILLS ARE EVIDENT. ACCURACY AND ATTN TO DETAIL DID SUFFER. THIS RPT IS BEING DISCUSSED WITH MY AVIATION DIRECTOR AND OTHER CREW MEMBERS EMPHASIZING THE NEED FOR CONSTANT VIGILANCE WITH CERTAIN CREW MEMBERS. IT IS HOPED THAT WE CAN CORRECT THIS SITUATION.