ALTDEV XING RESTR NOT MET; DSCNT DURING CLB CLRNC.

Narrative

AT XA55Z; 40 NM SW OF ONM; ZAB CLRED US FROM FL290 TO FL330 WITH A REQUIREMENT TO BE LEVEL IN 5 MINS. WE USED VERT SPD AT 1000 FPM TO MEET THE TIME LIMIT. DURING THE CLB; AIRSPD DECREASED TO 240 KTS. ATC DIRECTED A TURN. I USED 10 DEGS OF BANK. AT FL325; WITH LIGHT CHOP; I [PUSHED ALT HOLD TO LEVELOFF; BUT AIRSPD CONTINUED TO DECREASE. AT 220 KTS; I DISCONNECTED THE AUTOPLT AND BEGAN A DSCNT. THE CAPT INFORMED ATC. IT WAS NECESSARY TO DSND TO FL315 TO RECOVER AIRSPD. MOUNTAIN WAVE TURB WAS FORECAST IN THIS AREA AND LATER; WHEN LEVEL AT FL330; OUR AIRSPD VARIED PLUS OR MINUS 10 KTS. ATC DID NOT INDICATE THAT ANY CONFLICT OCCURRED. LESSONS LEARNED: 1) WATCH TIGHT CLB OR DSCNT RESTRS FROM ATC. 2) VERT SPD MODE CAN BITE YOU AT HIGH ALT. 3) MOUNTAIN WAVE MAY CAUSE AIRSPD OR PITCH CHANGES IN THE CLB. SUPPLEMENTAL INFO FROM ACN 299612: PERFORMANCE COMPUTER INDICATED FURTHER CLB TO FL330 AVAILABLE AND I CONFIRMED GROSS WTS LOADED IN COMPUTER MATCHED ACFT. DISPATCH WX INDICATED AREA OF MODERATE TURB AND MOUNTAIN WAVE.