B737 FLT CREW EXPERIENCES FLAP ASYMMETRY DURING APPROACH AND EXECUTES GAR. FLAPS ARE MISTAKENLY LOWERED TO 15 USING ALTERNATE FLAP SWITCH WHILE PERFORMING QRH PROCEDURE.

Narrative

ON FINAL APCH WE NOTICED THE FLAPS WERE NOT EXTENDING; INDICATING 0 FLAPS. THERE WAS A 1-2 DEG SPLIT BTWN THE FLAPS IN THE UP POS INDICATED BY THE GAUGE. WE EXECUTED A GAR AND ACCOMPLISHED THE ASYMMETRICAL FLT CTL CHKLIST. WE LANDED UNEVENTFULLY AND WERE UNAWARE OF A MISTAKE UNTIL AFTER WE LANDED AND REVIEWED THE CHKLIST ON THE GND. WE MISINTERPED STEP 2 AND LOWERED THE FLAPS TO 15 DEGS. WITH ASYMMETRIC FLAPS; WE SHOULD HAVE LEFT THE FLAPS IN THE ORIGINAL SETTING. CREW COORD COULD HAVE BEEN BETTER WITH ASSIGNING TASKS GIVING BOTH PLTS THE OPPORTUNITY TO REVIEW THE CHKLIST BEFORE ACCOMPLISHING THE CHKLIST. SUPPLEMENTAL INFO FROM ACN 808646: AFTER REVIEWING THE CHKLIST ON THE GND AFTER THE INCIDENT; I REALIZED MY ERROR. IN RETROSPECT; I REALIZE I RUSHED MYSELF AND DID NOT THOROUGHLY READ THE CHKLIST WHICH ULTIMATELY LED TO MY ERROR. IN ADDITION; MY DECISION TO BEGIN APPLYING THE CHKLIST WHILE THE FO WAS FLYING REMOVED HIM FROM THE PROCESS. WHILE IT WAS A GOOD DECISION TO BRING HIM BACK INTO THE PROCESS; I SHOULD HAVE HAD HIM BEGIN THE CHKLIST FROM THE TOP INSTEAD OF PICKING UP FROM WHERE I LEFT OFF WHICH WOULD HAVE HIGHLIGHTED MY MISTAKE. TO PREVENT THIS PROB IN THE FUTURE I WILL STRESS GOOD CREW CHKLIST DISCIPLINE AND THOROUGH REVIEW OF THE PROCS BEFORE APPLICATION OF THE CHKLIST.