Narrative:

On V8 I experienced moderate turbulence and requested higher altitude than my 12000 ft request, 13000 ft request. Cleared for 15000 ft. Still turbulence. Cleared to 17000 ft. Able to maintain altitude penetrating in and out of cloud tops. On V244 after have, experienced roller coaster. Holding attitude indicator level the plane would be carried 1000 plus ft in a few seconds, hold the new altitude for a few seconds and be plunged back down approximately the same number of ft. (At an indicated of 115 KTS.) ground speed on LORAN was 197 KTS. I was able to maintain heading using very shallow turns. Center asked if I was a turbo and had oxygen. Fortunately, I had gone to cedar city and refilled my tank. At 19000 ft I had a fairly smooth ride in the thick of clouds with intervals of clear. I estimate I was in the top 500-1000 ft of the clouds. No rain at my altitudes, just clouds. At the time I was receiving my instructions I experienced another updraft and was at 20000 ft within seconds. My compliments to ZDV for clearing me for a block of altitude on my own radial. I could only hold the plane attitude level. I had tried to chase the altitude but that only made the deviations greater. For safety, I felt a constant airspeed and level altitude were best. Monitoring cos I learned the wind was a factor and asked ZDV for WX at both cos and apa where I would be willing to be diverted. Quickly and efficiently they obtained both WX. Cos had 27 KT gusts and apa had 10 plus KT gusts. I requested apa. Quickly, ZDV gave me a new clearance and I was very happy to leave the clouds and land uneventfully. ZDV has my compliments on efficiently and quickly handling what could have been a bad situation. I would like to thank them for a good job and den approach. The WX shifts were too quick for the reporting system. I chose a south approach and cos instead of den to avoid the WX. Tops of 14000 ft became 20000 ft within mins.

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Original NASA ASRS Text

Title: WILD RIDE ON A MOUNTAIN WAVE PRODUCES AN ALTDEV ALT EXCURSIONS OF THE SMA. LOSS OF ACFT CTL.

Narrative: ON V8 I EXPERIENCED MODERATE TURB AND REQUESTED HIGHER ALT THAN MY 12000 FT REQUEST, 13000 FT REQUEST. CLRED FOR 15000 FT. STILL TURB. CLRED TO 17000 FT. ABLE TO MAINTAIN ALT PENETRATING IN AND OUT OF CLOUD TOPS. ON V244 AFTER HAVE, EXPERIENCED ROLLER COASTER. HOLDING ATTITUDE INDICATOR LEVEL THE PLANE WOULD BE CARRIED 1000 PLUS FT IN A FEW SECONDS, HOLD THE NEW ALT FOR A FEW SECONDS AND BE PLUNGED BACK DOWN APPROX THE SAME NUMBER OF FT. (AT AN INDICATED OF 115 KTS.) GND SPD ON LORAN WAS 197 KTS. I WAS ABLE TO MAINTAIN HDG USING VERY SHALLOW TURNS. CTR ASKED IF I WAS A TURBO AND HAD OXYGEN. FORTUNATELY, I HAD GONE TO CEDAR CITY AND REFILLED MY TANK. AT 19000 FT I HAD A FAIRLY SMOOTH RIDE IN THE THICK OF CLOUDS WITH INTERVALS OF CLR. I ESTIMATE I WAS IN THE TOP 500-1000 FT OF THE CLOUDS. NO RAIN AT MY ALTS, JUST CLOUDS. AT THE TIME I WAS RECEIVING MY INSTRUCTIONS I EXPERIENCED ANOTHER UPDRAFT AND WAS AT 20000 FT WITHIN SECONDS. MY COMPLIMENTS TO ZDV FOR CLRING ME FOR A BLOCK OF ALT ON MY OWN RADIAL. I COULD ONLY HOLD THE PLANE ATTITUDE LEVEL. I HAD TRIED TO CHASE THE ALT BUT THAT ONLY MADE THE DEVS GREATER. FOR SAFETY, I FELT A CONSTANT AIRSPD AND LEVEL ALT WERE BEST. MONITORING COS I LEARNED THE WIND WAS A FACTOR AND ASKED ZDV FOR WX AT BOTH COS AND APA WHERE I WOULD BE WILLING TO BE DIVERTED. QUICKLY AND EFFICIENTLY THEY OBTAINED BOTH WX. COS HAD 27 KT GUSTS AND APA HAD 10 PLUS KT GUSTS. I REQUESTED APA. QUICKLY, ZDV GAVE ME A NEW CLRNC AND I WAS VERY HAPPY TO LEAVE THE CLOUDS AND LAND UNEVENTFULLY. ZDV HAS MY COMPLIMENTS ON EFFICIENTLY AND QUICKLY HANDLING WHAT COULD HAVE BEEN A BAD SIT. I WOULD LIKE TO THANK THEM FOR A GOOD JOB AND DEN APCH. THE WX SHIFTS WERE TOO QUICK FOR THE RPTING SYS. I CHOSE A S APCH AND COS INSTEAD OF DEN TO AVOID THE WX. TOPS OF 14000 FT BECAME 20000 FT WITHIN MINS.

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.