FLT ASSIST AS SMA PLT FLIES INTO IMC AT NIGHT.

Narrative

DURING A VFR FLT FROM SBA TO CCR; IN INADVERTENTLY FLEW INTO IMC. I HAD FLOWN FROM CCR TO SBA EARLIER THAT DAY AND WAS ABLE TO STAY ABOVE THE CLOUD LAYERS (WHICH WERE ABOUT 9000 FT AT THAT TIME). I LEFT SBA LATER THAN I ORIGINALLY INTENDED TO LEAVE. IN RETROSPECT; I SHOULD NOT HAVE LEFT SBA AT A TIME THAT WOULD REQUIRE NIGHT VFR FLT GIVEN THE CLOUD CONDITIONS. AT THE TIME I THOUGHT I WOULD BE ABLE TO SEE AND AVOID THE CLOUDS (PROBABLY BECAUSE PRIOR NIGHT FLYING EXPERIENCE TOOK PLACE ON EITHER MOON LIGHT OR CLR DAYS). I WAS ABLE TO AVOID CLOUDS FOR THE FIRST PART OF THE FLT BY CLBING OR DSNDING. CLOUDS WERE STILL VISIBLE BECAUSE IT WAS DUSK. AFTER PASSING THE PRB VOR; I CAME UPON A LARGE CLOUD FRONT. I INITIALLY TRIED TO CLB OVER IT; BUT SOON ELECTED TO DSND BELOW IT BECAUSE THE TOPS WERE ABOVE 12500 FT AND I DID NOT HAVE SUPPLEMENTAL OXYGEN ON BOARD. I DID NOT NOTICE ENTERING IMC AT FIRST (AND; IN FACT; REMEMBER BEING CURIOUS WHY THE ANTI-COLLISION LIGHTS WERE ILLUMINATING THE COCKPIT AND CAUSING A STROBE EFFECT ON THE PROP). I WAS PROBABLY IN IMC FOR SEVERAL MINS; WHEN I NOTICED THAT I COULD NO LONGER SEE GND LIGHTS. SHORTLY THEREAFTER; I NOTICED THAT THE TURN COORDINATOR WAS PEGGED IN A L TURN; THE ATTITUDE INDICATOR SHOWED A 45-60 DEGS L BANK; AND THE DIRECTIONAL GYROSCOPE WAS SPINNING RAPIDLY. ABOUT THIS TIME; THE AIRSPD INDICATOR DROPPED TO 60 KTS; THEN TO 0. BASED LARGELY ON AN ARTICLE IN THE FEB/93 ISSUE OF THE FAA PUBLISHED NORCAL AVIATION REVIEW; CALLED 170 SECONDS; MY INST TRAINING TO DATE (ABOUT 10 PLUS HRS); AND OTHER AVIATION SAFETY PUBS; I RECOGNIZED THE SIGNS OF A 'GRAVEYARD SPIRAL' AND WAS ABLE TO RETURN THE PLANE TO STRAIGHT AND LEVEL FLT. I IMMEDIATELY TURNED ON PITOT HEAT; CONTACTED ATC; DECLARED AN URGENCY SIT; AND REQUESTED VECTORS TO THE NEAREST ARPT; WHICH HAPPENED TO BE SNS. ATC WAS VERY HELPFUL AND COOPERATIVE; WHICH HELPED RELIEVE THE STRESS. I AM CONVINCED THAT WITHOUT THE INST TRAINING I HAVE RECEIVED (I'M WORKING ON AN INST RATING NOW); I WOULD NOT HAVE RECOGNIZED THE PROB UNTIL IT WAS TOO LATE. THE REAL CAUSE HERE WAS BAD JUDGEMENT DUE TO A LACK OF APPRECIATION OF THE DANGER OF NIGHT VFR.