DSND TOO LOW ON NDB APCH WHEN WHITE OUT CONDITIONS CAUSE DECEPTIVE PERSPECTIVE.

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WE BROKE OUT ON THE NDB 9 APCH AT PORTLAND IN (PLD) BUT COULD ONLY SEE OUT THE SIDE WINDOWS BECAUSE BOTH FRONT WINDOWS WERE COVERED WITH ICE. WE CIRCLED THE ARPT TWICE AND CHKED OUT THE RWY FOR SNOW ACCUMULATION AND IT APPEARED TO BE IN GOOD SHAPE. ON BASE LEG WE COULD SEE THE RWY THROUGH L SIDE WINDOW. ON FINAL WE DSNDED TOO LOW DUE TO LACK OF OUTSIDE REFS; COMBINED WITH PROBABLY WRONG ALTIMETER SETTING. SUDDENLY; I (COPLT) NOTICED THAT WE WERE DANGEROUSLY LOW AND PULLED BACK ON THE YOKE; AS THE AIRPLANE WENT FROM NOSE DOWN TO NOSE UP THE WHEELS TOUCHED THE GND (DEFINITELY NOT THE RWY). THE PLT ADDED PWR AND WE TOOK OFF AGAIN. THE WHEELS TOUCHED THE GND NO LONGER THAN 1 SECOND. WE RPTED MISSED APCH TO FORT WAYNE APCH AND REQUESTED ILS 5. ON THE ILS 5 I COULD SEE THE ALS AND THE RWY LIGHT THROUGH THE R SIDE OF FRONT WINDSHIELD. AS WE CAME CLOSER AND LOWER THE RWY EDGE LIGHTS WERE CLRLY VISIBLE THROUGH BOTH L AND R SIDE WINDOWS SO I HAD A SENSE OF DEPTH AND COULD MAKE A SAFE LNDG. AFTER LNDG WE CHKED OUT THE AIRPLANE; NO DAMAGE; ABOUT 1/3 INCH OF ICE ON WINDSHIELD; 1/3 INCH ICE ON ALL OTHER PARTS OF AIRPLANE. AS WE SAW THAT WE HAD ICE ON FRONT WINDOWS WE SHOULD HAVE DIVERTED TO FORT WAYNE; WHICH HAS LONGER AND WIDER RWYS THAN PLD; INSTEAD OF TRYING TO MAKE IT INTO PLD.