A MAINT SUPERVISOR REPORTS THAT A B717-200 LEFT ENGINE THRUST REVERSER DID NOT DEPLOY ON LANDING. THE REVERSER DID NOT HAVE THE LOCKOUT 'REMOVE BEFORE FLIGHT' STREAMER HANGING OUT OF THE THRUST REVERSER CONTROL PANEL.

Narrative

IN THE EARLY MORNING; ACFT X'S MAINT LOGBOOK WAS BEING CLOSED OUT AND THE MAINT WORK WAS BEING COMPLETED. THERE HAD BEEN LOG DISCREPANCIES FOR THE R THRUST REVERSER BEING LOCKED OUT; THOSE DISCREPANCIES WERE SIGNED OFF. AN ADDITIONAL BLOCK IN THE LOGBOOK HAD BEEN INITIALED THAT THE THRUST REVERSERS WERE LOCKED OUT. ASSUMING THAT IT HAD BEEN USED AS AN ADDITIONAL LOG FOR THE R; I SIGNED THEM OFF NOT AWARE THAT IT HAD ALSO BEEN USED TO LOCK OUT THE L THRUST REVERSER. UPON LNDG; THE THRUST REVERSER DID NOT DEPLOY. MAINT CTL WAS NOTIFIED AND THE THRUST REVERSER WAS UN-BYPASSED. THE THRUST REVERSER DID NOT HAVE THE LOCKOUT 'REMOVE BEFORE FLT' STREAMER HANGING OUT OF THE DOOR. THIS WOULD HAVE CAUGHT THE ATTN OF THE MAINT CREW WORKING ON THE ACFT THAT MORNING AS WELL AS THE FLT CREW DURING PREFLT. MAINT PERSONNEL SHOULD ENSURE THAT ANY STREAMERS ATTACHED TO LOCKOUT PINS SHOULD BE VISIBLE WHEN COMPONENTS ARE LOCKED OUT AND ALL MAINT ACTIONS SHOULD BE INVESTIGATED BEFORE SIGNING THEM OFF AND NOT ASSUMED THAT THEY WERE A PART OF OTHER MAINT THAT WAS CLOSED OUT.