EA32 OVERSHOT THE TURN TO FINAL WHILE CONDUCTING AN AUTOMATED APCH.

Narrative

WHILE OPERATING AS ACR FLT ABC (LAS-MSP) ON APCH TO MSP; FLT ABC WAS CLRED FOR THE VISUAL APCH TO RWY 12R. THE CAPT WAS THE PF (FIRST TRIP SINCE IOE). WITH THE AUTOPLT ENGAGED; THE CAPT ARMED THE AUTOFLT SYS TO CAPTURE THE LOC FOR RWY 12R. AT THE SAME TIME; I WAS LOOKING FOR TFC (A C130) AT OUR 11-12 O'CLOCK POS. HE WAS VISIBLE ON OUR TCASII; BUT NOT VISUALLY. I WAS ALSO CLEANING UP THE MCDU; FLT PLAN; READYING US FOR THE APCH. THE AUTOPLT LOCKED ONTO THE LOC AND STARTED ITS R TURN TO JOIN ON. I DID NOT REALIZE THE CAPT WAS TRYING TO INTERCEPT AT APPROX A 90 DEG ANGLE TO THE RWY. THE ACFT FLEW THROUGH THE RWY 12R FINAL AS IT STARTED ITS TURN AND FLEW INTO THE RWY 12L FINAL AS IT WAS CORRECTING. EITHER APCH OR THE TWR CTLR ADVISED US OF OUR OVERFLYING FINAL. BY THIS TIME WE WERE CORRECTING BACK TO RWY 12R AND ADVISED HIM WE WERE CORRECTING. WE RECEIVED NO TCASII OR GPWS WARNINGS. I WAS NEVER ABLE TO HAVE VISUAL CONTACT WITH OUR TFC. FLT ABC LANDED AT MSP RWY 12R WITHOUT ANY FURTHER PROBS. I DO NOT BELIEVE WE CAUSED ANY PROBS FOR OUR TFC. I BELIEVE THIS PROB MAY HAVE BEEN CAUSED BY ATTEMPTING TO JOIN THE LOC WITH A FAR TOO LARGE OF AN INTERCEPT ANGLE. THE ACFT AUTOMATION IS NOT SET UP FOR THESE LARGE TOLERANCES.