 |
37000 Feet | Browse and search NASA's Aviation Safety Reporting System |
|
A B737NG encountered intense mountain wave over the rocky mountains and descended to a lower altitude.
| Attributes | |
| ACN | 882373 |
| Time | |
| Date | 201004 |
| Local Time Of Day | 1801-2400 |
| Place | |
| Locale Reference | ZDV.ARTCC |
| State Reference | CO |
| Environment | |
| Flight Conditions | VMC |
| Light | Night |
| Aircraft 1 | |
| Make Model Name | B737 Next Generation Undifferentiated |
| Operating Under FAR Part | Part 121 |
| Flight Phase | Cruise |
| Flight Plan | IFR |
| Person 1 | |
| Function | First Officer |
| Experience | Flight Crew Last 90 Days 247 Flight Crew Type 2500 |
| Events | |
| Anomaly | Deviation - Altitude Excursion From Assigned Altitude Deviation - Procedural Clearance Deviation - Speed All Types Inflight Event / Encounter Weather / Turbulence |
Narrative:
As we approached the front range of the rockies we heard of a B737 unable to maintain rvsm at fl 400 due to mountain wave turbulence. We elected to go down to 380 in an effort to not have the same issue. Approximately 40 east of ALS; we encountered the wave. At first it was just an airspeed deviation. Then it intensified and we had a 30 knot loss of airspeed as the jet went up 100'. The aircraft then lost 600' while having a 2000 fpm descent. At that point the autothrottles disengaged. Denver center was extremely helpful and even asked us if we wanted to go down below rvsm airspace. They gave us a pilot discretion descent to fl 290. We stopped at FL340 and encountered no more mountain wave. Our dispatch let us know prior to departure that there had been some mountain wave in that area; but that the plots had expired and we should not have any problems.
Original NASA ASRS Text
Title: A B737NG encountered intense mountain wave over the Rocky Mountains and descended to a lower altitude.
Narrative: As we approached the front range of the Rockies we heard of a B737 unable to maintain RVSM at FL 400 due to mountain wave turbulence. We elected to go down to 380 in an effort to not have the same issue. Approximately 40 east of ALS; we encountered the wave. At first it was just an airspeed deviation. Then it intensified and we had a 30 knot loss of airspeed as the jet went up 100'. The aircraft then lost 600' while having a 2000 fpm descent. At that point the autothrottles disengaged. Denver Center was extremely helpful and even asked us if we wanted to go down below RVSM airspace. They gave us a Pilot discretion descent to FL 290. We stopped at FL340 and encountered no more mountain wave. Our Dispatch let us know prior to departure that there had been some mountain wave in that area; but that the plots had expired and we should not have any problems.
Data retrieved from NASA's ASRS site as of April 2012 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.