LGT HAS TCASII RA; COMPLIES WITH CLB.

Narrative

WE WERE LEVEL AT 10000 FT ON AUTOPLT WITH ALT HOLD ENGAGED ON THE MOXEE ARR INTO PDX. WE HAD JUST RECEIVED A FREQ CHANGE FROM ZSE TO PORTLAND APCH WHEN THE TCASII GAVE US A TA. THE INTRUDING ACFT WAS 11:30 TO 12 O'CLOCK ON OUR TCASII DISPLAY AND 500 FT BELOW US. AS THE OTHER ACFT APCHED; THE VERT SEPARATION DECREASED TO 200 FT AND THE TCASII ISSUED AN RA AND COMMANDED A CLB. WE COMPLIED WITH THE TCASII COMMAND AND CLBED TO 11200 FT WHEN WE RECEIVED A CLR OF CONFLICT. I NOTIFIED ZSE IMMEDIATELY AND THEN SWITCHED TO PORTLAND APCH CTL AND ADVISED THEM OF THE TCASII RA. WE THEN RESUMED THE ARR WITH NO FURTHER PROBS. AS WE PASSED THE OTHER ACFT I SAW IT AT OUR 9 O'CLOCK POS AND SLIGHTLY LOWER. WE WERE ADVISED IT WAS AN SMA. THE INITIAL TCASII ALERT OCCURRED AT ABOUT THE SAME TIME AS THE FREQ CHANGE AND DISTRACTED US FROM CHANGING FREQS IMMEDIATELY WHICH PREVENTED US FROM GETTING APCH CTL ADVISORIES. HOWEVER; THE MOST CONCERNING FACTOR WAS THAT THE INTRUDING ACFT APPEARED TO BE CLBING TO OUR ALT ON A COLLISION COURSE. ANOTHER FACTOR IN VISUALLY ACQUIRING A SMALL ACFT AT OUR 12 O'CLOCK POS IS THE DECK ANGLE OF OUR ACFT AT 250 KTS; WHICH DOES NOT ALLOW GOOD FORWARD VISIBILITY WITHOUT PHYSICALLY TRYING TO LOOK OVER THE GLARE SHIELD.