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B737 captain reported encountering severe mountain wave in the vicinity of publication that resulted in speed and altitude excursions.
| Attributes | |
| ACN | 1357484 |
| Time | |
| Date | 201605 |
| Local Time Of Day | 1201-1800 |
| Place | |
| Locale Reference | ZDV.ARTCC |
| State Reference | CO |
| Environment | |
| Flight Conditions | VMC |
| Light | Daylight |
| Aircraft 1 | |
| Make Model Name | B737 Next Generation Undifferentiated |
| Operating Under FAR Part | Part 121 |
| Flight Phase | Cruise |
| Flight Plan | IFR |
| Person 1 | |
| Function | Captain Pilot Flying |
| Qualification | Flight Crew Air Transport Pilot (ATP) |
| Experience | Flight Crew Last 90 Days 182 Flight Crew Type 5500 |
| Events | |
| Anomaly | Deviation - Altitude Excursion From Assigned Altitude Deviation - Speed All Types Inflight Event / Encounter Weather / Turbulence |
Narrative:
At FL410 we were cruising with very light mountain wave (mtw) at 52 NM west of pueblo (publication) VOR; we then heard (other carrier) request altitude block and deviation for severe mountain wave encounter at FL390; altitude plus or minus 200 feet; airspeed plus or minus 30 knots. The location of encounter was at 45 NM west of pueblo crossing the rockies. I did notice very slight variations at FL410; when suddenly this wave hit us (45 NM west of publication); full strength the airspeed went straight beyond the barber poll 10 knots into vmo/mmo [maximum operating speed]; speed attained was 252 KIAS or mach .83. I did everything in my power to abate the acceleration; ats-off; power idle; and speed brakes flight detent. Our altitude variation was over 50-180 feet; denver ARTCC gave us a 30 degrees offsite vector to the right with a block altitude FL410-390; and we reported the severe mountain wave. I used control wheel steering pitch to maintain level attitude; thereafter over publication the event receded. It lasted only four seconds; but was definitely severe and unforecasted at that location. Both maintenance and dispatch were advised and a write up was entered.preventative measures: better mtw forecast and predictions. Alternate routing. But the mtw was unpredictable and very localized; seemed in the wake of pike's peak.
Original NASA ASRS Text
Title: B737 Captain reported encountering severe mountain wave in the vicinity of PUB that resulted in speed and altitude excursions.
Narrative: At FL410 we were cruising with very light Mountain Wave (MTW) at 52 NM west of Pueblo (PUB) VOR; we then heard (other carrier) request altitude block and deviation for severe mountain wave encounter at FL390; altitude plus or minus 200 feet; airspeed plus or minus 30 knots. The location of encounter was at 45 NM west of Pueblo crossing the Rockies. I did notice very slight variations at FL410; when suddenly this wave hit us (45 NM west of PUB); full strength the airspeed went straight beyond the barber poll 10 knots into VMO/MMO [maximum operating speed]; speed attained was 252 KIAS or Mach .83. I did everything in my power to abate the acceleration; ATS-OFF; Power Idle; and SPEED BRAKES FLIGHT DETENT. Our altitude variation was over 50-180 feet; Denver ARTCC gave us a 30 degrees offsite vector to the right with a block altitude FL410-390; and we reported the severe mountain wave. I used Control Wheel Steering Pitch to maintain level attitude; thereafter over PUB the event receded. It lasted only four seconds; but was definitely severe and unforecasted at that location. Both Maintenance and Dispatch were advised and a write up was entered.Preventative Measures: Better MTW forecast and predictions. Alternate routing. But the MTW was unpredictable and very localized; seemed in the wake of Pike's Peak.
Data retrieved from NASA's ASRS site 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.