EMB145 DISCOVERS AIRBORNE THAT THE RIGHT MLG WAS PINNED BY MAINT FOR A TIRE CHANGE AND NEVER REMOVED.

Narrative

WE WERE UNABLE TO RETRACT THE R MAIN LNDG GEAR AFTER TKOF; DURING INITIAL CLBOUT. WE STAYED IN THE TFC PATTERN AND LOWERED THE GEAR NORMALLY WITH A NORMAL INDICATION. WE RETURNED TO THE FIELD WITH A NORMAL VISUAL APCH AND THERE WAS NO FURTHER COMPLICATIONS. THE ACFT WAS BELOW MAX LNDG WT BY 1000 LBS AND NEVER EXCEEDED ANY LIMITATIONS. WE INITIALLY SAW A RED GEAR INDICATION ON THE R MAIN LNDG GEAR IMMEDIATELY AFTER TKOF AND ATC BROUGHT IT TO OUR ATTN SHORTLY AFTERWARDS. WE STAYED IN THE TFC PATTERN AND DID A NORMAL VISUAL APCH TO A LNDG. THE GEAR WAS EXTENDED NORMALLY WITH A NORMAL 3 GREEN INDICATION. THERE WAS NO OVERWT LNDG AND NO LIMITATION EXCEEDED. WE HAD A WRITE-UP IN THE LOG THAT OUR #4 TIRE WAS BALD AND WORN. MAINT CAME TO THE AIRPLANE TO CHANGE THE TIRE AND INSTALLED 1 GEAR PIN IN THE R MAIN LNDG GEAR ONLY. THERE WAS NEVER ANY WRITE-UP THAT A GEAR PIN WAS EITHER INSTALLED OR REMOVED DURING THE MAINT PROC. THE CAPT DID A VISUAL INSPECTION ON THE R MAIN AFTER MAINT FINISHED WORKING ON THE ACFT AND MISSED THE FLAGGED GEAR PIN UP IN THE R MAIN. PRIOR TO DEPARTING THE GATE; WE RAN THROUGH THE RECEIVING CHKLIST AND I LOOKED BACK SEEING THE GEAR PIN FLAPS BUT DIDN'T COUNT HOW MANY WERE ACTUALLY ON BOARD. I NOTED THAT ALL 4 GEAR PINS WERE ON BOARD AS A COMPLETED CHKLIST ITEM. MAINT HAD FAILED TO NOTE IN THE LOG THAT THE GEAR PIN WAS INSTALLED AS STANDARD MAINT PROC FOR CHANGING A TIRE. THE CAPT MISSED THE GEAR PIN FLAG ON THE VISUAL INSPECTION AFTER THE MAINT PROC WAS ACCOMPLISHED. I ASSUMED SINCE SEEING GEAR PIN FLAPS BEHIND THE CAPT'S SEAT THAT ALL 4 WERE THERE AND NOTED IT ON THE RECEIVING CHKLIST THAT ALL 4 WERE ONBOARD. IT WAS; HOWEVER; A 15 HR DUTY DAY; THE LAST LEG OF THE DAY; AND MISSED BY ALL 3 PEOPLE.