A B737-200 WAS DISPATCHED IN NON COMPLIANCE WITH AN OBSERVER'S SEAT DEFERRED 2 DAYS OVER THE MEL LIMITS.

Narrative

I WAS WORKING THE NIGHT OF DEC/THU/02. THE NEXT MORNING (DEC/FRI/02) BTWN XA-BX00; WHILE AUDITING THE MEL UPDATE LIST FOR THE -300 TYPE ACFT; I FOUND THAT MEL 25-11 HAD EXCEEDED THE MEL'S 2 DAY 'DROP DEAD' TIME LIMIT. ACFT WAS NOT IN A MAINT BASE AND THE MEL WAS STILL OPEN. I REALIZED THAT A MAJOR ERROR HAD BEEN MADE. THIS ACFT HAD BEEN GNDED IN ZZZ ALL DAY DEC/THU/02 FROM XE00 UNTIL XA25 ON DEC/FRI/02 DUE TO BAD WX IN ZZZ. I THOUGHT THIS ACFT WOULD REMAIN IN ZZZ AND THE MEL WORKED BECAUSE A MAINT ROUTING/WORK REQUEST WAS ISSUED TO PLANNING AND DISPATCH ON DEC/WED/02 TO WORK AND CLR THIS TIME LIMITED MEL. ZZZ MAINT WAS NEVER ASSIGNED TO WORK THIS ACFT. WITHOUT MAINT CTL'S KNOWLEDGE OR APPROVAL; PLANNING REASSIGNED THE MEL TO MAINT THE NEXT DAY AND DISPATCH ROUTED THEN FLEW TO ZZZ1. I INFORMED MY TEAM LEAD OF THE SIT AND WE BOTH DECIDED; IN LIGHT OF THE ERROR ALREADY MADE; TO SUBMIT AN MEL EXTENSION. MY TEAM LEAD THEN NOTIFIED THE DIRECTOR OF MAINT; AS REQUIRED; FOR THE APPROVAL OF AN MEL EXTENSION. THE MEL EXTENSION WAS APPROVED AND SUBMITTED. I FULLY UNDERSTAND THERE IS NO EXTENSION OF AN 'A' CATEGORY MEL. DUE TO REQUIRED WX RELATED MAINT AFFECTING A MULTITUDE OF ACFT IN THE NE; THIS EXTENSION ERROR WAS NOT REALIZED AT THE TIME BY ME; MY TEAM LEAD; OR THE DIRECT OF MAINT. THERE ARE DESIGNED CHKPOINTS THAT SHOULD HAVE CAUGHT THIS MISTAKE. THESE CHKPOINTS SEEMED TO HAVE ERRED IN THIS PARTICULARLY UNUSUAL SIT.