MEM TWR CTLR DESCRIBED SEVERAL INSTANCES OF ASDE AND AMASS DATA BLOCK LOSSES; SUGGESTING ASDE AND AMASS SHOULD BE AVAILABLE FOR RWY 27 OPS.

Narrative

I WAS WORKING LCL CTL 1 AND 2 (LC1/LC2) COMBINED. MEMPHIS WAS LNDG RWYS 36L/36C/36R AND RWY 27. I WAS RESPONSIBLE FOR ALL RWY 36 ARRS. ANOTHER CTLR WAS STAFFED AT LCL CTL 3 FOR ALL RWY 27 ARRS. GND CTL 1 AND 2 WERE COMBINED AS USUAL; AND THIS SINGLE GND CTLR IS RESPONSIBLE FOR ALL ACFT THAT HAVE LANDED ON RWYS 36L/36C/36R. EACH ACFT THAT LANDS ON RWYS 36L/36C/36R IN THIS CONFIGN; MUST THEN CROSS RWY 27; WHICH IS AN ACTIVE ARR AND DEP RWY. THERE ARE 6 INTERSECTING TXWYS THAT CROSS RWY 27; AND OUR ASDE/AMASS EQUIP DOES NOT PROVIDE ADEQUATE COVERAGE FOR THESE AREAS. THE ASDE/AMASS DISPLAY IS LOCATED BTWN LCL CTL 1 AND GND CTL 1. AS EACH RWY 36L ARR LANDED AND THEN TAXIED NBOUND ON TXWYS M AND N; EACH ASSOCIATED ASDE/AMASS DATA TAG WOULD DROP OFF OF THE ASDE/AMASS DISPLAY AS THE ACFT PASSED THE RAMP JUST S OF TXWY A; AND S OF THE DEP END OF RWY 27. DURING ONE 15 MIN PERIOD; I OBSERVED SEVERAL ACFT LAND ON RWY 36L; TAXI N ON TXWYS M AND N; AND EACH ASSOCIATED ASDE/AMASS DATA TAG DROPPED OFF OF THE DISPLAY. USING RWY 27 DURING THIS TYPE OF OP IS DIFFICULT ENOUGH AS IT IS. NOT HAVING THE ABILITY TO USE ASDE/AMASS ON RWY 27 MAKES FOR A LESS SAFE OP. THIS EQUIP IS NOT CERTIFIED FOR USE ON RWY 27; BUT IT SHOULD BE. THIS IS WHERE THE VAST MAJORITY OF OUR RWY XINGS TAKE PLACE; AND IT HAPPENS EACH AND EVERY NIGHT ON THE INBOUND AND OUTBOUND OP. THE FAA NEEDS TO INSTALL ADEQUATE EQUIP TO ENSURE THE SAFE OP OF ALL RWY XINGS DURING ALL TIMES OF THE DAY/NIGHT; AND UNDER ALL WX CONDITIONS.