Narrative:

I filed an IFR flight plan in small aircraft (my personal aircraft) direct publication V-83 to alamosa, initial altitude 11000 ft. Took off at 40 MST from cos airport arsa and radar vectors to publication. Handoff to publication approach at 11000 ft and radar vector 180 degrees west of publication VOR. 10 mi south vector 160 degrees to intercept V-83. I requested 12000 ft and climbed. Ceiling in the area was about 13000 ft MSL scattered to broken. 30 NM south of publication I requested climb to 14000 ft and was approved. At bloke intersection I made the turn and leveled at 14000 ft in the clouds. Outside air temperature minus 5 degrees C, TAS 105 KTS smooth air. At 50 NM DME ALS VORTAC. Airspeed slowly dropped to vy and vertical speed started dropping rapidly. I took off my oxygen mask and started to transmit on the microphone when denver advised that my transponder showed 13500 ft. I acknowledged and advised that I was making a 180 degree turn to return to publication. They gave me a direct clearance to publication and I established on a 005 degree radial on course to publication. I stopped the descent at 13000 ft and after a couple of mins I broke out in the clear and idented walsenburg airport. I cancelled IFR and denver told me to squawk 1200. Looking back to la veta pass the way was clear 3 mi north of V-83 into alamosa and I advised ZDV of my intentions. Over alamosa I advised denver radio of my arrival. Winds at 12000/320 degrees /15 KTS 18000/320 19 KTS forecast and I didn't anticipate any more than light turbulence over la veta pass. I must have received the second mountain wave from mount blanca to the northwest of course. I could have varied course 10 degrees right around cloud and filed IFR/VFR on top at 12500 ft and stayed out of clouds 3 mi north of V-83 as I normally do. I have to get my oxygen mask microphone fixed so I can talk more rapidly. I won't fly west on V-83 IFR at minimum flight altitude (14000 ft) any more!

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Original NASA ASRS Text

Title: SMA ON IFR FLT PLAN DSNDS BELOW MEA DUE TO MOUNTAIN WAVE ACTIVITY.

Narrative: I FILED AN IFR FLT PLAN IN SMA (MY PERSONAL ACFT) DIRECT PUB V-83 TO ALAMOSA, INITIAL ALT 11000 FT. TOOK OFF AT 40 MST FROM COS ARPT ARSA AND RADAR VECTORS TO PUB. HDOF TO PUB APCH AT 11000 FT AND RADAR VECTOR 180 DEGS W OF PUB VOR. 10 MI S VECTOR 160 DEGS TO INTERCEPT V-83. I REQUESTED 12000 FT AND CLBED. CEILING IN THE AREA WAS ABOUT 13000 FT MSL SCATTERED TO BROKEN. 30 NM S OF PUB I REQUESTED CLB TO 14000 FT AND WAS APPROVED. AT BLOKE INTXN I MADE THE TURN AND LEVELED AT 14000 FT IN THE CLOUDS. OUTSIDE AIR TEMP MINUS 5 DEGS C, TAS 105 KTS SMOOTH AIR. AT 50 NM DME ALS VORTAC. AIRSPD SLOWLY DROPPED TO VY AND VERT SPD STARTED DROPPING RAPIDLY. I TOOK OFF MY OXYGEN MASK AND STARTED TO XMIT ON THE MIKE WHEN DENVER ADVISED THAT MY XPONDER SHOWED 13500 FT. I ACKNOWLEDGED AND ADVISED THAT I WAS MAKING A 180 DEG TURN TO RETURN TO PUB. THEY GAVE ME A DIRECT CLRNC TO PUB AND I ESTABLISHED ON A 005 DEG RADIAL ON COURSE TO PUB. I STOPPED THE DSCNT AT 13000 FT AND AFTER A COUPLE OF MINS I BROKE OUT IN THE CLR AND IDENTED WALSENBURG ARPT. I CANCELLED IFR AND DENVER TOLD ME TO SQUAWK 1200. LOOKING BACK TO LA VETA PASS THE WAY WAS CLR 3 MI N OF V-83 INTO ALAMOSA AND I ADVISED ZDV OF MY INTENTIONS. OVER ALAMOSA I ADVISED DENVER RADIO OF MY ARR. WINDS AT 12000/320 DEGS /15 KTS 18000/320 19 KTS FORECAST AND I DIDN'T ANTICIPATE ANY MORE THAN LIGHT TURB OVER LA VETA PASS. I MUST HAVE RECEIVED THE SECOND MOUNTAIN WAVE FROM MOUNT BLANCA TO THE NW OF COURSE. I COULD HAVE VARIED COURSE 10 DEGS R AROUND CLOUD AND FILED IFR/VFR ON TOP AT 12500 FT AND STAYED OUT OF CLOUDS 3 MI N OF V-83 AS I NORMALLY DO. I HAVE TO GET MY OXYGEN MASK MIKE FIXED SO I CAN TALK MORE RAPIDLY. I WON'T FLY W ON V-83 IFR AT MINIMUM FLT ALT (14000 FT) ANY MORE!

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.