XING RESTR NOT MET ON APCH TO HPN; NY.

Narrative

WHILE FLYING THE BOUNO 3 ARR (BOUNO.BOUNO3) INTO HPN ARPT; WE HAD JUST CROSSED DPK AND WERE AT 15000 FT MSL. I; AS THE PNF; HAD TO GO OFF FREQ #1 TO GET THE ATIS. I THEN MADE THE APPROPRIATE COORD FOR THE CAPT TO TAKE CTL OF FREQ #1; WHICH HE DID. AS I WAS SWITCHING UP FREQ #2; I WAS ABLE TO HEAR ATC GIVE US THE FOLLOWING CLRNC; 'CROSS GWENY AT 11000 FT; DSND AND MAINTAIN 6000 FT.' THE CAPT ACKNOWLEDGED AND READ BACK THE CLRNC WITH ATC. I SUBSEQUENTLY WENT ON TO GET THE ATIS; AND WAS UNABLE TO CONFIRM THAT THE CAPT HAD COMPLIED WITH THE ATC CLRNC. UPON MY RETURN TO FREQ #1; I DISCOVERED THAT WE HAD NOT YET REACHED GWENY; BUT WE WERE AT APPROX 10000 FT AND CONTINUING OUR DSCNT TO 6000 FT. THE XING RESTR OF 11000 FT AT GWENY HAD BEEN VIOLATED. ATC CONTRIBUTING FACTORS: 1) WHEN POSSIBLE MAY BE BETTER TO GIVE PLTS ALT ASSIGNMENTS ONE AT A TIME; NOT COMBINED. 2) CHANGE THE PHRASEOLOGY OF ATC CLRNCS. PLT CONTRIBUTING FACTORS: 1) I; AS THE OFF FREQ PLT; SHOULD TRY AND DIVERT ATTN BTWN GETTING ATIS; AND VERIFY THAT CAPT DOES WHAT HE SHOULD. 2) CONSIDER USING POST-IT NOTES; ETC; IN COCKPIT TO ASSURE THAT WE MAKE THE ALT XINGS.