FLT CREW OF A320 ENCOUNTER MOUNTAIN WAVE OVER ROCKY MOUNTAINS; GAIN 800 FT DURING OVERSPD PROTECTION MANEUVER AND THEN LOSE 2000 FT TO PREVENT STALL ON BACK SIDE OF WAVE.

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AIRFRAME OVERSPD WITH RESULTANT ALTDEV. WE WERE LEVEL AT FL330; 30 MI E OF THE ALS VOR. THE FLT HAD BEEN SMOOTH; THE SEATBELT SIGN WAS OFF. ATC HAD BEEN QUERIED AS TO RIDE CONDITIONS AND THE RESPONSE WAS JUST OCCASIONAL LIGHT CHOP AT OUR ALT. THE FMA'S WERE MACH; ALT; CRUISE; NAV. I WAS USING SELECTED SPD; VARYING THE MACH BTWN .76 AND .80 AS WE HAD EXPERIENCED SOME LIGHT MOUNTAIN WAVE AND A CAT RPT WAS IN EFFECT FOR MOUNTAIN WAVE IN OUR SECTOR. THE COCKPIT LIGHTS WERE TURNED DOWN; AND I FELT I WAS CLOSELY MONITORING THE SPD IN AN EFFORT TO BAL THE WAVE ACTIVITY WITH TRYING TO MAINTAIN OUR FLT PLAN MACH NUMBER OF .80. WE WERE 25 MINS LATE DUE TO A MECHANICAL PROB PRIOR TO LEAVING. WITHOUT WARNING; WE EXPERIENCED A SEVERE TURBULENT JOLT AND MOUNTAIN WAVE; ACCELERATING 20-25 KTS; AT LEAST 10 KTS INTO THE OVERSPD RANGE. THE ACFT PITCHED UP AND GAINED ALMOST 1000 FT. INSTINCTIVELY (FROM MY BOEING DAYS); I DISCONNECTED THE AUTOPLT AND THEN THE AUTOTHRUST SYS. I BROUGHT THE THRUST TO IDLE AND TRIED TO HOLD THE ACFT STEADY SO AS NOT TO EXCEED WHAT LOOKED TO BE A CRITICAL PITCH ANGLE. AT SOME POINT; THE ACFT LOST ENERGY AND STARTED DECELERATING TOWARDS VLS. I PITCHED THE NOSE DOWN; EVENTUALLY LOSING ALMOST 2000 FT. BEFORE WE HAD A CHANCE TO CALL ATC; ATC ASKED US HOW OUR RIDE WAS. WE MADE THE SEVERE TURB/MOUNTAIN WAVE RPT WITH THEM AS WE WERE CLBING BACK TO FL330. ALL THE PAX (IT WAS A FULL FLT) WERE SEATED AT THE TIME OF THE INCIDENT; BUT 2 FLT ATTENDANTS WERE STANDING IN THE AFT GALLEY. THEY WERE ABLE TO GRAB AND HOLD ON TO THE HANDLES LOCATED NEAR THE DOORS. THE CONTENTS OF THE GALLEY WERE DISTRIBUTED ACROSS THE GALLEY FLOOR. NEITHER OF THEM WERE HURT (THANK GOODNESS). THE OTHER 2 FLT ATTENDANTS WERE SEATED IN THEIR JUMPSEATS. WE RPTED THE INCIDENT TO DISPATCH AND WROTE UP THE OVERSPD AND THE SEVERE TURB ENCOUNTER IN THE LOGBOOK. I HAVE 3 QUESTIONS: 1) I FEEL AS THOUGH I MIGHT HAVE EXACERBATED THE SIT BY GETTING RID OF THE AUTOFLT SYS. WITH MY LEVEL OF EXPERIENCE IN THE AIRPLANE; I WAS VERY NARROWLY FOCUSED ON THE ADI; AND USED WHAT I FEEL THIS MORNING WERE ABRUPT MOVEMENTS TO TRY TO COUNTERACT THE FORCES. SHOULD I HAVE LEFT THE AUTOPLT ON AND LET THE AIRPLANE PROTECT ITSELF? 2) WHAT CRITERIA CONSTITUTES A SEVERE MOUNTAIN WAVE ENCOUNTER? 3) IS THE IMPLICATION OF STRUCTURAL DAMAGE IN A SEVERE TURB ENCOUNTER A REASON TO GIVE MORE CONSIDERATION THAN I DID TO A POSSIBLE DIVERSION? I HOPE WE CAN HELP ANSWER SOME OF THESE QUESTIONS WITH THE INFO. THIS SEEMS TO BE A BIT TRICKIER THAN RIDING CAMELS! SUPPLEMENTAL INFO FROM ACN 609480: THE CAPT WAS ACTING AS THE PF AS REQUIRED FOLLOWING IOE. THE CAPT DID EXACTLY WHAT I WOULD HAVE DONE IF I WERE THE PF. HOWEVER; IT IS WORTH DISCUSSING WHETHER PLT ACTIONS MIGHT HAVE EXAGGERATED THE SIT. NOTE: THIS IS THE SECOND OVERSPD SIT I HAVE EXPERIENCED ON THE AIRBUS. BOTH INSTANCES OCCURRED SUDDENLY; WITH LITTLE WARNING; AND NO REACTION TIME TO FIX THE SIT. CALLBACK CONVERSATION WITH RPTR ACN 609477 REVEALED THE FOLLOWING INFO: THE CAPT ADVISED THAT THE ACR IS GIVING THIS EVENT SIGNIFICANT SCRUTINY. INVESTIGATION OF THE DFDR AND THE QUALITY ASSURANCE RECORDER DETERMINED THAT DESPITE THE DISCONNECT OF THE AUTOPLT BY THE CAPT; THE ACTUAL CLB WAS INITIATED BY THE OVERSPD PROTECTIVE MECHANISM OF THE FMGC. THE SUBSEQUENT DSCNT WAS AT A SPD ABOVE THE 'ALPHA' PROTECTION FLOOR AND WAS THE RESULT OF MANUAL PLT INPUT RESPONDING TO RAPIDLY DECAYING AIRSPD IN THE DOWNWARD FLOW SIDE OF THE WAVE. IT IS CERTAIN THAT; HAD THE CREW NOT INTERVENED; THE ALPHA PROTECTION MECHANISM WOULD HAVE PRODUCED A RESULT NOT UNLIKE THE PLT INPUT SINCE DSCNT AND MAX THRUST WOULD HAVE BEEN NECESSARY IN SOME COMBINATION TO ARREST THE DECAYING AIRSPD. THE CAPT AND THE COMPANY ARE CONCERNED REGARDING THE IMPLICATIONS OF THESE SORTS OF FMS DRIVEN AUTOMATIC RECOVERY MECHANISMS IN THE FUTURE WHEN RVSM AIRSPACE REDUCES SEPARATION AT FLT LEVELS CONSISTENT WITH SEVERE MOUNTAIN WAVE PROBABILITY TO ONLY 1000 FT. RPTR SUGGESTED THAT CONSIDERATION OUGHT TO BE TAKEN TO RESTRICTING RTES WITH KNOWN MOUNTAIN WAVE ISSUES SO AS TO NOT ALLOW RVSM SEPARATION CRITERIA.