37000 Feet | Browse and search NASA's Aviation Safety Reporting System |
|
Attributes | |
ACN | 383947 |
Time | |
Date | 199710 |
Day | Thu |
Local Time Of Day | 1801 To 2400 |
Place | |
Locale Reference | atc facility : cos |
State Reference | CO |
Altitude | msl bound lower : 33000 msl bound upper : 33500 |
Environment | |
Flight Conditions | VMC |
Light | Night |
Aircraft 1 | |
Controlling Facilities | artcc : zdv tower : str |
Operator | common carrier : air carrier |
Make Model Name | A320 |
Operating Under FAR Part | Part 121 |
Navigation In Use | Other Other |
Flight Phase | cruise other |
Flight Plan | IFR |
Person 1 | |
Affiliation | company : air carrier |
Function | flight crew : captain oversight : pic |
Qualification | pilot : atp pilot : commercial pilot : instrument pilot : flight engineer |
Experience | flight time last 90 days : 190 flight time total : 5200 flight time type : 250 |
ASRS Report | 383947 |
Person 2 | |
Affiliation | company : air carrier |
Function | flight crew : first officer |
Qualification | pilot : instrument pilot : flight engineer pilot : commercial pilot : atp |
Experience | flight time last 90 days : 98 flight time total : 3000 flight time type : 78 |
ASRS Report | 383953 |
Events | |
Anomaly | altitude deviation : excursion from assigned altitude inflight encounter other other anomaly other |
Independent Detector | other flight crewa |
Resolutory Action | flight crew : returned to intended course or assigned course |
Consequence | Other |
Supplementary | |
Primary Problem | Weather |
Air Traffic Incident | other |
Narrative:
Airbus A320, mountain wave encounter. Both myself and first officer relatively low timers in aircraft. My first mountain wave encounter in this aircraft. In previous aircraft I relied on throttle movement to help alert me to mountain wave. In the airbus there is no throttle movement. About the time I perceived we were encountering mountain wave we got an overspd warning, the aircraft initiated a climb and disengaged the autoplt and autothrottles. The sidestick in this situation has reduced authority/authorized (I later read). I immediately took the controls and reduced the throttles and began a nose over. Because of the reduced authority/authorized of the side-stick and my attempt to avoid negative 'G's' we climbed approximately 500 ft before I managed to get a descent going. We were off our assigned flight level no more than 30 seconds, and above 33300 ft no more than 10 seconds. I remember being briefed on this in training, but I suspect it is something that cannot be taught in school to a level of proficiency without a lot of training. In a training environment where we are already putting 10 pounds in a 5 pound bag, I don't believe there is the room or resource for something like this to be taught extensively, something that one may or may not encounter. The next time I suspect mountain wave is possible or see it forecast, I'll give extra thought to decreasing our mach number only to help eliminate this problem, or at least to give me that extra second or two to react.
Original NASA ASRS Text
Title: AN A320 ACFT ENCOUNTERED MOUNTAIN WAVE WHICH RESULTED IN INSTANTANEOUS SPD INCREASE. ACFT, AS DESIGNED, WENT INTO OVERSPD PROTECTION, PITCH UP (TO SLOW), THROTTLES TO IDLE AND REDUCED SIDESTICK AUTH (PITCH CTL). ALTDEV OCCURRED DUE TO PITCH UP AND FLC'S RELUCTANCE TO CREATE NEGATIVE G'S PUSHING OVER.
Narrative: AIRBUS A320, MOUNTAIN WAVE ENCOUNTER. BOTH MYSELF AND FO RELATIVELY LOW TIMERS IN ACFT. MY FIRST MOUNTAIN WAVE ENCOUNTER IN THIS ACFT. IN PREVIOUS ACFT I RELIED ON THROTTLE MOVEMENT TO HELP ALERT ME TO MOUNTAIN WAVE. IN THE AIRBUS THERE IS NO THROTTLE MOVEMENT. ABOUT THE TIME I PERCEIVED WE WERE ENCOUNTERING MOUNTAIN WAVE WE GOT AN OVERSPD WARNING, THE ACFT INITIATED A CLB AND DISENGAGED THE AUTOPLT AND AUTOTHROTTLES. THE SIDESTICK IN THIS SIT HAS REDUCED AUTH (I LATER READ). I IMMEDIATELY TOOK THE CTLS AND REDUCED THE THROTTLES AND BEGAN A NOSE OVER. BECAUSE OF THE REDUCED AUTH OF THE SIDE-STICK AND MY ATTEMPT TO AVOID NEGATIVE 'G'S' WE CLBED APPROX 500 FT BEFORE I MANAGED TO GET A DSCNT GOING. WE WERE OFF OUR ASSIGNED FLT LEVEL NO MORE THAN 30 SECONDS, AND ABOVE 33300 FT NO MORE THAN 10 SECONDS. I REMEMBER BEING BRIEFED ON THIS IN TRAINING, BUT I SUSPECT IT IS SOMETHING THAT CANNOT BE TAUGHT IN SCHOOL TO A LEVEL OF PROFICIENCY WITHOUT A LOT OF TRAINING. IN A TRAINING ENVIRONMENT WHERE WE ARE ALREADY PUTTING 10 LBS IN A 5 LB BAG, I DON'T BELIEVE THERE IS THE ROOM OR RESOURCE FOR SOMETHING LIKE THIS TO BE TAUGHT EXTENSIVELY, SOMETHING THAT ONE MAY OR MAY NOT ENCOUNTER. THE NEXT TIME I SUSPECT MOUNTAIN WAVE IS POSSIBLE OR SEE IT FORECAST, I'LL GIVE EXTRA THOUGHT TO DECREASING OUR MACH NUMBER ONLY TO HELP ELIMINATE THIS PROB, OR AT LEAST TO GIVE ME THAT EXTRA SECOND OR TWO TO REACT.
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.