What was found
GPS-L INVALID INFLIGHT REPLACED MMR-1 IAW AMM 34-31-42, LOST GPS SIGNAL ONCE AFTER INSTALLATION. REINSTALLED ORIG MMR-1 AFTER OBSERVING GPS-L COORDINATES BLANKING MULTIPLE TIMES. REPLACED LEFT GPS ANTENNA IAW AMM 34-58-02 USING PREFERRED METHOD (GEL GASKET) IAW EC3458-01006B.CONFIRMED SUCCESSFUL INSTALLATION TEST. OBSERVED STEADY GPS-L POSITION COORDINATES FOR EXTENDED PERIOD, LEFT GPS SYS OK FOR SVC.