Narrative:

I was bringing a new purchased C177RG from grand strand, sc, to home base in nashua, nh, after 4 days in an intensive aircraft familiarization and VFR/IFR refresher program. Leg from crew to refuel/lunch stop at mrb was at 7000 ft, after climbing to clear light to moderate turbulence below. North of mrb, had increasing difficulty maintaining altitude, and received clearance to 9000 ft. I had alerted controller on each frequency change that I was being carried above and below altitude by turbulence, (I believe I reported not able to hold altitude, but able to average it) but had not requested a block altitude as I was able to maintain within +/-150 ft. My adjustable seat was raised fully, for better over-the-cowl visibility conditions. As the airway headed closer to the mountain ridges, a particularly severe downdraft dropped the aircraft 200+ ft, lifted every unsecured item, and gave me (belted in) a good crack against the headliner. I went to climb power, and reduced airspeed 50+ mph in an attempt to climb back to 9000 ft. The updraft side of the wave caught me in this confign, and the vsi pegged up. I had throttled back to 12 inches, as airspeed went well into the yellow (165-170 KIAS) and I was considering dropping gear as center called 'showing 9300 ft.' I could respond with the push-to-talk, even with both hands on the wheel, and reported I was doing everything physically possible to maintain altitude. Soon after this, I moved westward over the ridge line and out of the wave condition and was able to regain altitude control. One lesson from this event: treat moderate plus turbulence like thunderstorm cells, and lower seat. I had considered that advice meant to reduce night sight exposure to lightning flash, rather than adding head clearance! Also, I should have been more definitive with ATC, requesting an adequate block earlier, rather than fighting the WX condition which had me at airspeed well above maneuvering -- my 'informing' ATC of flight conditions wasn't adequate warning.

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Original NASA ASRS Text

Title: A C177 PLT, OVERFLYING THE MOUNTAINS OF WEST VIRGINIA, ENCOUNTERED TURB AND A MOUNTAIN WAVE CONDITION, RENDERING HIM INCAPABLE OF MAINTAINING ASSIGNED ALT.

Narrative: I WAS BRINGING A NEW PURCHASED C177RG FROM GRAND STRAND, SC, TO HOME BASE IN NASHUA, NH, AFTER 4 DAYS IN AN INTENSIVE ACFT FAMILIARIZATION AND VFR/IFR REFRESHER PROGRAM. LEG FROM CREW TO REFUEL/LUNCH STOP AT MRB WAS AT 7000 FT, AFTER CLBING TO CLR LIGHT TO MODERATE TURB BELOW. N OF MRB, HAD INCREASING DIFFICULTY MAINTAINING ALT, AND RECEIVED CLRNC TO 9000 FT. I HAD ALERTED CTLR ON EACH FREQ CHANGE THAT I WAS BEING CARRIED ABOVE AND BELOW ALT BY TURB, (I BELIEVE I RPTED NOT ABLE TO HOLD ALT, BUT ABLE TO AVERAGE IT) BUT HAD NOT REQUESTED A BLOCK ALT AS I WAS ABLE TO MAINTAIN WITHIN +/-150 FT. MY ADJUSTABLE SEAT WAS RAISED FULLY, FOR BETTER OVER-THE-COWL VISIBILITY CONDITIONS. AS THE AIRWAY HEADED CLOSER TO THE MOUNTAIN RIDGES, A PARTICULARLY SEVERE DOWNDRAFT DROPPED THE ACFT 200+ FT, LIFTED EVERY UNSECURED ITEM, AND GAVE ME (BELTED IN) A GOOD CRACK AGAINST THE HEADLINER. I WENT TO CLB PWR, AND REDUCED AIRSPD 50+ MPH IN AN ATTEMPT TO CLB BACK TO 9000 FT. THE UPDRAFT SIDE OF THE WAVE CAUGHT ME IN THIS CONFIGN, AND THE VSI PEGGED UP. I HAD THROTTLED BACK TO 12 INCHES, AS AIRSPD WENT WELL INTO THE YELLOW (165-170 KIAS) AND I WAS CONSIDERING DROPPING GEAR AS CTR CALLED 'SHOWING 9300 FT.' I COULD RESPOND WITH THE PUSH-TO-TALK, EVEN WITH BOTH HANDS ON THE WHEEL, AND RPTED I WAS DOING EVERYTHING PHYSICALLY POSSIBLE TO MAINTAIN ALT. SOON AFTER THIS, I MOVED WESTWARD OVER THE RIDGE LINE AND OUT OF THE WAVE CONDITION AND WAS ABLE TO REGAIN ALT CTL. ONE LESSON FROM THIS EVENT: TREAT MODERATE PLUS TURB LIKE TSTM CELLS, AND LOWER SEAT. I HAD CONSIDERED THAT ADVICE MEANT TO REDUCE NIGHT SIGHT EXPOSURE TO LIGHTNING FLASH, RATHER THAN ADDING HEAD CLRNC! ALSO, I SHOULD HAVE BEEN MORE DEFINITIVE WITH ATC, REQUESTING AN ADEQUATE BLOCK EARLIER, RATHER THAN FIGHTING THE WX CONDITION WHICH HAD ME AT AIRSPD WELL ABOVE MANEUVERING -- MY 'INFORMING' ATC OF FLT CONDITIONS WASN'T ADEQUATE WARNING.

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.