JNU FSS SPECIALIST DESCRIBED NEAR SEPARATION EVENT BETWEEN ARR AND DEP AFTER TWR HAD CLOSED; FLT CREW ATTEMPTED DEP AFTER VOID TIME OPPOSITE TO ARR.

Narrative

JNU TWR ISSUED A DEP CLRNC TO ACFT X AND CLOSED. JNU TWR DID NOT ADVISE ACFT X THEY HAD AN INBOUND STRIP ON ACFT Y. JNU AFSS CALLED ZAN CTLR TO ADVISE ACFT X WAS BEGINNING TO TAXI XA. ZAN ISSUED AN XB VOID TIME. ACFT Y WAS ON THE APCH INTO JNU FOR RWY 8. I INSTRUCTED ACFT X THAT HE WAS NOT TO DEPART AFTER XC00 WHILE HE WAS TAXIING FOR RWY 26. ACFT X ANNOUNCED THEY INTENDED TO DEPART. I JUMPED ON THE RADIO AND DEMANDED THAT ACFT X (HOLD FOR RELEASE!); THEN ADVISED ZAN. ZAN INFORMED ME TO ADVISE ACFT X HOLD FOR RELEASE. AS FSS SPECIALIST I AM NOT ALLOWED TO CTL TFC. ACFT X WAS DEPARTING AFTER THEIR VOID TIME DIRECTLY INTO ACFT Y. PROB: WITH NO RADAR AND THE FACT THAT JNU TWR IS CLOSED; NO ONE CAN PROVE THE EXACT TIME OF DEP. THIS HAPPENS ON A REGULAR BASIS WITH OPERATORS IN AN ATTEMPT TO SAVE FUEL. IF TWR STAYED OPEN; ACFT X WOULD HAVE BEEN INSTRUCTED TO HOLD SHORT OF RWY AND WAIT FOR THE ACFT Y. THIS IS POSITIVE CTL! WHEN THE TWR CLOSES AT PEAK ARR AND DEP EACH NIGHT; IT PLACES EXCESSIVE WORK AND COORD ON ZAN. ANCHORAGE CTLR WAS OVERWHELMED. FAA REDUCED SJU TWR HRS OF OP. WITH THE REDUCED TWR HRS; JNU AFSS HANDLES MOST OF THE FLTS THAT OCCUR AFTER CLOSING. JNU AFSS IS NOT LOCATED ON THE AIRFIELD AND CANNOT SEE THESE ACFT ARRIVE OR DEPART.