SMT PLT HAD ATTITUDE GYRO FAIL IN IMC CONDITIONS IN PDX CLASS E.

Narrative

AFTER TKOF AND JUST AFTER; ENTERED NIGHT LOW STRATUS AT ABOUT 1500 FT; AND 1700 FT AGL I LOST THE ALT GYRO. I WAS ABLE TO MAINTAIN COMPLETE CTL IN THE CLIMB AND LEVELED OFF AT 4000 FT IN VMC. I TOLD ATC OF THE PROB. THEY WANTED TO GIVE ME VECTORING FOR A NO GYRO ILS APCH. SINCE I COULD SEE A FAIRLY LARGE HOLE IN THE UNDERCAST AND THE ARPT WX WAS VFR AT THE TIME OF MY DEP I CANCELLED IFR AND DSNDED IN A SPIRAL THROUGH THE HOLE. ONCE UNDER THE LAYER AND AT ABOUT 500 TO 1000 FT AGL I BECAME CONFUSED AS TO WHICH DIRECTION I WAS HEADING. I CALLED THE TWR AND REQUESTED RIGHT BASE ENTRY TO RWY 12. THEY APPROVED IT. THEY COULD NOT SEE AND THEN THEY SAW ME IN A POS FOR A RIGHT BASE TO RWY 30 WHICH I FLEW TO THE RWY AND LANDED WITHOUT FURTHER INCIDENT. ON THE BASE LEG TWR ASKED MY ALT AND I BELIEVE I RESPONDED 400 FT. I WAS FLYING AROUND NORTH OF THE ARPT FOR SEVERAL MINS WITHOUT SEEING THE ARPT. DUE TO ARRIVING AND DEP IFR AND VFR TFC I WAS HESITANT TO ASK TWR FOR HELP LOCATING THE ARPT. ALSO KNOWING THAT THEY DID NOT KNOW HOW TO PROPERLY WORK THE GPS IN THIS ACFT AS THIS WAS THE FIRST TIME I HAD FLOWN THIS PARTICULAR AIRPLANE. DURING MY MANEUVERING DUE TO THE RAGGED CEILING I WAS FORCED TO FLY BELOW 500 FT AGL TO MAINTAIN VFR. I AM USED TO FLYING WITH AN SIC AND THE ADDITIONAL WORKLOAD WITH THE GYRO EMER APPARENTLY WAS TOO MUCH FOR ME TO COPE WITH AT THAT TIME IN AN UNFAMILIAR AIRPLANE. IF THE TWR HAD RADAR SVC THERE WOULD NOT HAVE BEEN ANY PROB GETTING BACK TO THE ARPT.