 |
37000 Feet | Browse and search NASA's Aviation Safety Reporting System |
|
A corporate pilot reported severe mountain wave activity and a brief moderate clear air turbulence encounter which disconnected the autopilot along with a 600 foot altitude loss.
| Attributes | |
| ACN | 1430665 |
| Time | |
| Date | 201703 |
| Local Time Of Day | 0601-1200 |
| Place | |
| Locale Reference | ZDV.ARTCC |
| State Reference | CO |
| Environment | |
| Flight Conditions | VMC |
| Light | Daylight |
| Aircraft 1 | |
| Make Model Name | Medium Transport |
| Operating Under FAR Part | Part 91 |
| Flight Phase | Cruise |
| Route In Use | Vectors |
| Flight Plan | IFR |
| Person 1 | |
| Function | Captain Pilot Flying |
| Qualification | Flight Crew Air Transport Pilot (ATP) Flight Crew Multiengine Flight Crew Instrument |
| Experience | Flight Crew Last 90 Days 40 Flight Crew Total 7400 Flight Crew Type 40 |
| Events | |
| Anomaly | Deviation - Altitude Excursion From Assigned Altitude Inflight Event / Encounter Loss Of Aircraft Control Inflight Event / Encounter Weather / Turbulence |
Narrative:
While cruising at FL350 ATC gave a vector heading to avoid an area of severe mountain wave activity. We complied with the request promptly and turned on passenger seatbelt sign on. A short time later [we] encountered moderate clear air turbulence and the autopilot disconnected. A few seconds later we encountered what I would describe as severe mountain wave and the aircraft was having difficulty maintaining altitude. Airspeed was +/-30 knots and we lost 600 feet of altitude while trying to fly out of this weather phenomena. The entire episode lasted no more than about 20 seconds. We immediately notified ATC of our altitude deviation and that we were attempting to climb back up to our assigned altitude. ATC acknowledged and offered reroute and altitude change. By that time things got a lot better and we were able to continue to our destination without any issues. There were no injuries to passengers.moderate to severe mountain wave was reported in the vicinity but no reports of any turbulence. We may have just encountered a pocket of moderate clear air turbulence at the same time as we encountered severe mountain wave.
Original NASA ASRS Text
Title: A corporate pilot reported severe mountain wave activity and a brief moderate clear air turbulence encounter which disconnected the autopilot along with a 600 foot altitude loss.
Narrative: While cruising at FL350 ATC gave a vector heading to avoid an area of severe mountain wave activity. We complied with the request promptly and turned on passenger seatbelt sign on. A short time later [we] encountered moderate clear air turbulence and the autopilot disconnected. A few seconds later we encountered what I would describe as severe mountain wave and the aircraft was having difficulty maintaining altitude. Airspeed was +/-30 knots and we lost 600 feet of altitude while trying to fly out of this weather phenomena. The entire episode lasted no more than about 20 seconds. We immediately notified ATC of our altitude deviation and that we were attempting to climb back up to our assigned altitude. ATC acknowledged and offered reroute and altitude change. By that time things got a lot better and we were able to continue to our destination without any issues. There were no injuries to passengers.Moderate to severe mountain wave was reported in the vicinity but no reports of any turbulence. We may have just encountered a pocket of moderate clear air turbulence at the same time as we encountered severe mountain wave.
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.