Narrative:

Shortly after leveloff at FL330, we experienced mountain wave activity that caused an altitude deviation. The waves started out minor, with a +/-100-200 ft deviance and gradually got worse. The biggest wave caused us to climb 700 ft (FL337) and descend 500 ft (FL325). I disconnected the autoplt and hand flew the aircraft in an attempt to stay at FL330. The power fluctuation was not as great. We never exceeded any engine limitations and only got a momentary overspd warning, so I elected to keep the autothrottles on. As I was flying, we received a frequency change from ZSE to ZLC. I informed the captain to please tell ATC that we could not maintain altitude, but he didn't. He wanted to 'wait to see how bad it'll get.' he also didn't notify ATC because neither sea nor slc questioned us about the deviation. So every time I deviated from the altitude, I asked him to notify ATC. It wasn't until we descended out of it and were level at our new altitude (FL280, I think) that he told ZLC that we had mountain wave activity and that we deviated +700 ft, -500 ft. To make matters worse, every time we hit the bottom of the wave, the flight attendants would ring the pilot call button to complain about the uncomfortable rides. So while the captain was on the radio with ATC and on the 'phone' with the flight attendants, I was left to fly the plane. I could have used help from the captain in flight director inputs or calling off airspds (mach speeds) and altitudes, and even rate of climb/descent, but I was left to do that myself. The input I gave was not taken under advisement, however, it all worked out. I talked to the flight attendants on the ground to explain what a mountain wave is and why it was an uncomfortable ride. They seemed to appreciate the explanation. The rapport between cabin and flight deck crew was negative, and it would have been easier to just drop the subject, but I felt that they had a right to know what went on. I tried to utilize CRM where the captain refused to.

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Original NASA ASRS Text

Title: FLC OF MD80 EXPERIENCED PLUS AND MINUS ALTDEVS DURING MOUNTAIN WAVE ENCOUNTER IN VICINITY OF REO.

Narrative: SHORTLY AFTER LEVELOFF AT FL330, WE EXPERIENCED MOUNTAIN WAVE ACTIVITY THAT CAUSED AN ALTDEV. THE WAVES STARTED OUT MINOR, WITH A +/-100-200 FT DEVIANCE AND GRADUALLY GOT WORSE. THE BIGGEST WAVE CAUSED US TO CLB 700 FT (FL337) AND DSND 500 FT (FL325). I DISCONNECTED THE AUTOPLT AND HAND FLEW THE ACFT IN AN ATTEMPT TO STAY AT FL330. THE PWR FLUCTUATION WAS NOT AS GREAT. WE NEVER EXCEEDED ANY ENG LIMITATIONS AND ONLY GOT A MOMENTARY OVERSPD WARNING, SO I ELECTED TO KEEP THE AUTOTHROTTLES ON. AS I WAS FLYING, WE RECEIVED A FREQ CHANGE FROM ZSE TO ZLC. I INFORMED THE CAPT TO PLEASE TELL ATC THAT WE COULD NOT MAINTAIN ALT, BUT HE DIDN'T. HE WANTED TO 'WAIT TO SEE HOW BAD IT'LL GET.' HE ALSO DIDN'T NOTIFY ATC BECAUSE NEITHER SEA NOR SLC QUESTIONED US ABOUT THE DEV. SO EVERY TIME I DEVIATED FROM THE ALT, I ASKED HIM TO NOTIFY ATC. IT WASN'T UNTIL WE DSNDED OUT OF IT AND WERE LEVEL AT OUR NEW ALT (FL280, I THINK) THAT HE TOLD ZLC THAT WE HAD MOUNTAIN WAVE ACTIVITY AND THAT WE DEVIATED +700 FT, -500 FT. TO MAKE MATTERS WORSE, EVERY TIME WE HIT THE BOTTOM OF THE WAVE, THE FLT ATTENDANTS WOULD RING THE PLT CALL BUTTON TO COMPLAIN ABOUT THE UNCOMFORTABLE RIDES. SO WHILE THE CAPT WAS ON THE RADIO WITH ATC AND ON THE 'PHONE' WITH THE FLT ATTENDANTS, I WAS LEFT TO FLY THE PLANE. I COULD HAVE USED HELP FROM THE CAPT IN FLT DIRECTOR INPUTS OR CALLING OFF AIRSPDS (MACH SPDS) AND ALTS, AND EVEN RATE OF CLB/DSCNT, BUT I WAS LEFT TO DO THAT MYSELF. THE INPUT I GAVE WAS NOT TAKEN UNDER ADVISEMENT, HOWEVER, IT ALL WORKED OUT. I TALKED TO THE FLT ATTENDANTS ON THE GND TO EXPLAIN WHAT A MOUNTAIN WAVE IS AND WHY IT WAS AN UNCOMFORTABLE RIDE. THEY SEEMED TO APPRECIATE THE EXPLANATION. THE RAPPORT BTWN CABIN AND FLT DECK CREW WAS NEGATIVE, AND IT WOULD HAVE BEEN EASIER TO JUST DROP THE SUBJECT, BUT I FELT THAT THEY HAD A RIGHT TO KNOW WHAT WENT ON. I TRIED TO UTILIZE CRM WHERE THE CAPT REFUSED TO.

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.