FO FAILS TO RESPOND TO COMMANDS FROM CAPT AND ATC.

Narrative

I WAS THE PNF ON A FERRY FLT FROM SNA TO CNO. AS WE LEVELED OFF AT 5000 FT AND COMPLETED THE AFTER TKOF CHKLIST AND CRUISE CHKS; I ADVISED THE PF I WAS GOING OFF THE PRIMARY ATC FREQ TO CHK THE ATIS AT CNO ON THE SECONDARY FREQ. THE PF RESPONDED THAT HE HAD CTL OF THE PRIMARY ATC FREQ. AFTER OBTAINING CNO'S ATIS; I RETURNED TO THE PRIMARY FREQ; WHERE SOCAL DEP WAS QUERYING; QUITE ANGRILY; IF WE COULD HEAR SOCAL DEP. SOCAL ADVISED THAT WE NEEDED TO CLB IMMEDIATELY TO 6000 FT FOR VFR TFC AT 5500 FT AND FOR DIRECTION OF TRAVEL. I RESPONDED WE WOULD CLB. THE PF DID NOT INITIATE A CLB IMMEDIATELY. I WAS ABOUT TO ASK THE PF WHEN HE WAS GOING TO CLB WHEN SOCAL AGAIN COMMANDED US TO CLB FOR VFR TFC AT 5500 FT. LUCKILY; THE VFR TFC HAD US IN SIGHT AND MAINTAINED SEPARATION. FINALLY; THE PF CLBED TO 6000 FT. THE REMAINDER OF THE FLT WAS NORMAL AND UNEVENTFUL. MY PERCEPTION OF THE SIT WAS THAT THE PF WAS 'OUT TO LUNCH' AND NOT KEEPING UP WITH ACFT. I HAVE NEVER SEEN THE PF BE SO PREOCCUPIED WITH OTHER THAN FLYING ON THE FLT DECK. IN THE FUTURE; I WILL ALWAYS MONITOR BOTH ATC FREQS TO HELP COVER THE OTHER PLT AND WILL TUG ON THE YOKE IF THE PF IS NOT CLBING.