Narrative:

Aircraft is an older model small aircraft. Reported ceiling was 2000'. We observed tops at 6500'. We were at 7000' MSL. Instructed to descend and maintain 3000'. Set up for trimmed 500 FPM descent. Entered cloud at about 6500'. It was a hostile cloud. For most of the time in the cloud we had most or all of the following: 800-1000 FPM updrafts/downdrafts; severe turbulence; rain/torrential rain; loud, deafening mexican rock music on the radio; and vertigo. Whenever I tried to turn slightly to maintain heading, I would suddenly find myself in a 45+ degree bank. Much of the time I couldn't read the INS for the fierce vibration. I feared the gyros would tumble but they didn't. Rain gushed in under the edge of the windshield. Periodically, an extraordinarily violent jerk or noise would distract me and cause me to lose my scan. Vertigo would immediately set in. It would take several mins of extreme concentration to make it subside. Most of the time I was at maneuvering speed and fighting to just control the aircraft. I may have had inadvertent deviations in heading and/or altitude. We had had some reports of transponder inaccuracy. Finally, we were instructor to descend and shoot the VOR approach for runway 7. When I broke out at 900', I was quite exhausted. Felt like I'd been chewed up and spit out. It was a sloppy approach, but I believed I stayed within minimums. 2 days later, had transponder fixed, radios dried out and windshield sealed. We had 2 broken wires at the blind encoder plug. Next time I encounter any situation equal to this, I intend to use the international urgent signal 'pan.' in retrospect, this was an urgent situation, though not distress. It could have developed to distress, however, under any one of several scenarios. But the controller gave me exactly the help I needed and it worked out ok.

Google
 

Original NASA ASRS Text

Title: GA SMT PLT ENCOUNTERS EXTREMELY ADVERSE CONDITIONS IN INS DESCENT AND BRIEFLY LOSES CTL OF THE ACFT.

Narrative: ACFT IS AN OLDER MODEL SMA. RPTED CEILING WAS 2000'. WE OBSERVED TOPS AT 6500'. WE WERE AT 7000' MSL. INSTRUCTED TO DSND AND MAINTAIN 3000'. SET UP FOR TRIMMED 500 FPM DSNT. ENTERED CLOUD AT ABOUT 6500'. IT WAS A HOSTILE CLOUD. FOR MOST OF THE TIME IN THE CLOUD WE HAD MOST OR ALL OF THE FOLLOWING: 800-1000 FPM UPDRAFTS/DOWNDRAFTS; SEVERE TURB; RAIN/TORRENTIAL RAIN; LOUD, DEAFENING MEXICAN ROCK MUSIC ON THE RADIO; AND VERTIGO. WHENEVER I TRIED TO TURN SLIGHTLY TO MAINTAIN HDG, I WOULD SUDDENLY FIND MYSELF IN A 45+ DEG BANK. MUCH OF THE TIME I COULDN'T READ THE INS FOR THE FIERCE VIBRATION. I FEARED THE GYROS WOULD TUMBLE BUT THEY DIDN'T. RAIN GUSHED IN UNDER THE EDGE OF THE WINDSHIELD. PERIODICALLY, AN EXTRAORDINARILY VIOLENT JERK OR NOISE WOULD DISTRACT ME AND CAUSE ME TO LOSE MY SCAN. VERTIGO WOULD IMMEDIATELY SET IN. IT WOULD TAKE SEVERAL MINS OF EXTREME CONCENTRATION TO MAKE IT SUBSIDE. MOST OF THE TIME I WAS AT MANEUVERING SPD AND FIGHTING TO JUST CTL THE ACFT. I MAY HAVE HAD INADVERTENT DEVIATIONS IN HDG AND/OR ALT. WE HAD HAD SOME RPTS OF XPONDER INACCURACY. FINALLY, WE WERE INSTRUCTOR TO DSND AND SHOOT THE VOR APCH FOR RWY 7. WHEN I BROKE OUT AT 900', I WAS QUITE EXHAUSTED. FELT LIKE I'D BEEN CHEWED UP AND SPIT OUT. IT WAS A SLOPPY APCH, BUT I BELIEVED I STAYED WITHIN MINIMUMS. 2 DAYS LATER, HAD XPONDER FIXED, RADIOS DRIED OUT AND WINDSHIELD SEALED. WE HAD 2 BROKEN WIRES AT THE BLIND ENCODER PLUG. NEXT TIME I ENCOUNTER ANY SITUATION EQUAL TO THIS, I INTEND TO USE THE INTL URGENT SIGNAL 'PAN.' IN RETROSPECT, THIS WAS AN URGENT SITUATION, THOUGH NOT DISTRESS. IT COULD HAVE DEVELOPED TO DISTRESS, HOWEVER, UNDER ANY ONE OF SEVERAL SCENARIOS. BUT THE CTLR GAVE ME EXACTLY THE HELP I NEEDED AND IT WORKED OUT OK.

Data retrieved from NASA's ASRS site as of July 2007 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.