Narrative:

The aircraft being flown was an AA5B/right (grumman 'tiger'). The route of flight was from mem to hts on an IFR flight plan. On filing the flight plan, the current WX for my destination and en route was checked. In addition, a radar plot of the en route WX was printed. Periodic in-flight WX checks for the destination were made with the local FSS, flight watch, and en route ATC. No center WX advisories were given and the destination WX, current and forecasted, did not indicate the in-flight WX encountered. Approximately a half an hour prior to entering the embedded level 5 thunderstorm, the en route ATC radar had gone out. It was shortly after the controller advised us of the radar outage and contact was lost, that the in-flight WX hazard was encountered. With heavy rain, vertical gusts, and loss of aircraft directional and navigation control rapidly deteriorating, I requested a heading out of the WX. I immediately advised the center controller of my in-flight conditions and he advised that his radar was still down. He asked if I wanted to declare an emergency and I replied yes. Within a few moments I regained aircraft control and flew into VMC conditions. I was then immediately handed off to hts approach controller. The aircraft and the occupants were not damaged or injured. Radar vectors to hts and a visual approach was made to a safe landing. Center ATC was very helpful. The cause of the above occurrence was a result of several mechanical, human, and nature performance factors, all of which came together to cause the inadvertent penetration (IMC) of a level 5 embedded thunderstorm.

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Original NASA ASRS Text

Title: A GRUMMAN 'TIGER' AA-5B HAD TO DECLARE AN EMER DUE TO PENETRATION OF A TSTM.

Narrative: THE ACFT BEING FLOWN WAS AN AA5B/R (GRUMMAN 'TIGER'). THE RTE OF FLT WAS FROM MEM TO HTS ON AN IFR FLT PLAN. ON FILING THE FLT PLAN, THE CURRENT WX FOR MY DEST AND ENRTE WAS CHKED. IN ADDITION, A RADAR PLOT OF THE ENRTE WX WAS PRINTED. PERIODIC INFLT WX CHKS FOR THE DEST WERE MADE WITH THE LCL FSS, FLT WATCH, AND ENRTE ATC. NO CTR WX ADVISORIES WERE GIVEN AND THE DEST WX, CURRENT AND FORECASTED, DID NOT INDICATE THE INFLT WX ENCOUNTERED. APPROX A HALF AN HR PRIOR TO ENTERING THE EMBEDDED LEVEL 5 TSTM, THE ENRTE ATC RADAR HAD GONE OUT. IT WAS SHORTLY AFTER THE CTLR ADVISED US OF THE RADAR OUTAGE AND CONTACT WAS LOST, THAT THE INFLT WX HAZARD WAS ENCOUNTERED. WITH HVY RAIN, VERT GUSTS, AND LOSS OF ACFT DIRECTIONAL AND NAV CTL RAPIDLY DETERIORATING, I REQUESTED A HDG OUT OF THE WX. I IMMEDIATELY ADVISED THE CTR CTLR OF MY INFLT CONDITIONS AND HE ADVISED THAT HIS RADAR WAS STILL DOWN. HE ASKED IF I WANTED TO DECLARE AN EMER AND I REPLIED YES. WITHIN A FEW MOMENTS I REGAINED ACFT CTL AND FLEW INTO VMC CONDITIONS. I WAS THEN IMMEDIATELY HANDED OFF TO HTS APCH CTLR. THE ACFT AND THE OCCUPANTS WERE NOT DAMAGED OR INJURED. RADAR VECTORS TO HTS AND A VISUAL APCH WAS MADE TO A SAFE LNDG. CTR ATC WAS VERY HELPFUL. THE CAUSE OF THE ABOVE OCCURRENCE WAS A RESULT OF SEVERAL MECHANICAL, HUMAN, AND NATURE PERFORMANCE FACTORS, ALL OF WHICH CAME TOGETHER TO CAUSE THE INADVERTENT PENETRATION (IMC) OF A LEVEL 5 EMBEDDED TSTM.

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.