Commercial Fixed Wing
Flight Crew Multiengine; Flight Crew Instrument; Flight Crew Air Transport Pilot (ATP)
Flight Crew Last 90 Days 118; Flight Crew Total 2768; Flight Crew Type 1795
Deviation - Altitude Excursion From Assigned Altitude; Deviation - Speed All Types; Deviation / Discrepancy - Procedural Clearance; Inflight Event / Encounter Weather / Turbulence; Inflight Event / Encounter Loss Of Aircraft Control
Flight Crew Returned To Clearance
Weather
While climbing out of Denver airspace at 36;000 feet on our way to 37;000 feet we encountered a strong mountain wave. I had just requested 39;000 feet with Denver center when the incident occurred. The Controller passed me on to a different frequency and at that time we encountered the mountain wave. Almost immediately the airspeed increased into the high-speed Q and our vertical speed increased to over 8000 ft./min. We were able to level off at 37;800 feet and contact the new Controller. Upon contact I notified the Controller that we were above are signed altitude due to a mountain wave. We descended back down to 37;000 feet and then we were cleared to 39;000 feet.
We were level FL360. The aircraft dipped below cruise altitude causing VMO exceedance. I disengaged autopilot to return to normal parameters when the upside of the mountain wave climbed us to FL368 before I was able to descend back to FL360. First Officer noted a climb rate approaching 8;000 FPM. ATC was notified and no traffic conflicts were present.
Air carrier flight crew reported encountering a strong mountain wave resulting in an exceedance of Vmo/Mmo and an altitude deviation.