Narrative:

I was en route from el paso, tx, to montgomery field in san diego in a brand new small aircraft. At approximately :00 to :30 pm, I encountered thunderstorms en route and had to make an unauthorized landing at the gila bend af auxiliary base in gila bend, az. Before departing el paso, tx, I received a standard WX briefing which indicated a chance of thunderstorms and isolated rain showers due to the low pressure and unstable air mass in the area. After receiving my briefing, I filed an IFR flight plan the route was defined: el paso V16 tucson, V66 mission bay, direct montgomery field. While in route I climbed to 12000 ft and was talking with albuquerque center. At about 25 mi east of tucson albuquerque center came with a WX advisory convective SIGMET which extended 50 mi southwest of phoenix to 10 mi ese of yuma. A band of thunderstorms 30 mi wide with little or no movement. After checking with flight watch, I decided to amend my routing to: after gila bend VOR, V94 blythe VOR, V460 julian VOR direct montgomery field. Talking with albuquerque center the controller said that an small aircraft about 15 mins ahead of me had gone through that route at about 10000 ft and had experienced only light rain. Also at that time center was working another aircraft going eastbound at 7000 ft and this aircraft had ground contact and a smooth ride. As soon as the aircraft passed, I asked for lower and was cleared to 9000 ft, but was still in the clouds and could not see. I asked center for 7000 ft and was cleared to 7000 ft. By this time I was about 20 mi east of gila bend VOR and I had ground contact. At about 10 mi east of the VOR I suddenly experienced severe turbulence and heavy rain. The turbulence was severe enough that the door popped open, the tow bar in the back hit ceiling of the aircraft several times, the aircraft was almost impossible to control and visibility was reduced to about a mi in less than a min. It was at this time I cancelled IFR and started to head for the gila bend airport but visibility was poor so I decided to land at the gila bend air force base since I had it in sight. I started to look for a frequency to get in touch with the air force base but could not locate one in my commercial charts or on the low en route charts at the time. So the decision was made to go ahead and land at the air force base by announcing my intentions over unicom frequency.

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Original NASA ASRS Text

Title: SMA ENCOUNTERS SEVERE TURB. PRECAUTIONARY LNDG AT AF BASE.

Narrative: I WAS ENRTE FROM EL PASO, TX, TO MONTGOMERY FIELD IN SAN DIEGO IN A BRAND NEW SMA. AT APPROX :00 TO :30 PM, I ENCOUNTERED TSTMS ENRTE AND HAD TO MAKE AN UNAUTH LNDG AT THE GILA BEND AF AUX BASE IN GILA BEND, AZ. BEFORE DEPARTING EL PASO, TX, I RECEIVED A STANDARD WX BRIEFING WHICH INDICATED A CHANCE OF TSTMS AND ISOLATED RAIN SHOWERS DUE TO THE LOW PRESSURE AND UNSTABLE AIR MASS IN THE AREA. AFTER RECEIVING MY BRIEFING, I FILED AN IFR FLT PLAN THE RTE WAS DEFINED: EL PASO V16 TUCSON, V66 MISSION BAY, DIRECT MONTGOMERY FIELD. WHILE IN RTE I CLBED TO 12000 FT AND WAS TALKING WITH ALBUQUERQUE CENTER. AT ABOUT 25 MI E OF TUCSON ALBUQUERQUE CENTER CAME WITH A WX ADVISORY CONVECTIVE SIGMET WHICH EXTENDED 50 MI SW OF PHOENIX TO 10 MI ESE OF YUMA. A BAND OF TSTMS 30 MI WIDE WITH LITTLE OR NO MOVEMENT. AFTER CHKING WITH FLT WATCH, I DECIDED TO AMEND MY RTING TO: AFTER GILA BEND VOR, V94 BLYTHE VOR, V460 JULIAN VOR DIRECT MONTGOMERY FIELD. TALKING WITH ALBUQUERQUE CENTER THE CTLR SAID THAT AN SMA ABOUT 15 MINS AHEAD OF ME HAD GONE THROUGH THAT RTE AT ABOUT 10000 FT AND HAD EXPERIENCED ONLY LIGHT RAIN. ALSO AT THAT TIME CENTER WAS WORKING ANOTHER ACFT GOING EBOUND AT 7000 FT AND THIS ACFT HAD GND CONTACT AND A SMOOTH RIDE. AS SOON AS THE ACFT PASSED, I ASKED FOR LOWER AND WAS CLRED TO 9000 FT, BUT WAS STILL IN THE CLOUDS AND COULD NOT SEE. I ASKED CENTER FOR 7000 FT AND WAS CLRED TO 7000 FT. BY THIS TIME I WAS ABOUT 20 MI E OF GILA BEND VOR AND I HAD GND CONTACT. AT ABOUT 10 MI E OF THE VOR I SUDDENLY EXPERIENCED SEVERE TURB AND HVY RAIN. THE TURB WAS SEVERE ENOUGH THAT THE DOOR POPPED OPEN, THE TOW BAR IN THE BACK HIT CEILING OF THE ACFT SEVERAL TIMES, THE ACFT WAS ALMOST IMPOSSIBLE TO CTL AND VISIBILITY WAS REDUCED TO ABOUT A MI IN LESS THAN A MIN. IT WAS AT THIS TIME I CANCELLED IFR AND STARTED TO HEAD FOR THE GILA BEND ARPT BUT VISIBILITY WAS POOR SO I DECIDED TO LAND AT THE GILA BEND AIR FORCE BASE SINCE I HAD IT IN SIGHT. I STARTED TO LOOK FOR A FREQ TO GET IN TOUCH WITH THE AIR FORCE BASE BUT COULD NOT LOCATE ONE IN MY COMMERCIAL CHARTS OR ON THE LOW ENRTE CHARTS AT THE TIME. SO THE DECISION WAS MADE TO GO AHEAD AND LAND AT THE AIR FORCE BASE BY ANNOUNCING MY INTENTIONS OVER UNICOM FREQ.

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.