 |
37000 Feet | Browse and search NASA's Aviation Safety Reporting System |
|
A B737-800 flight crew encountered a mountain wave and began descending to recover a 35 KTS airspeed loss while awaiting ATC descent clearance.
| Attributes | |
| ACN | 1068503 |
| Time | |
| Date | 201302 |
| Local Time Of Day | 1801-2400 |
| Place | |
| Locale Reference | ZOA.ARTCC |
| State Reference | CA |
| Environment | |
| Flight Conditions | VMC |
| Light | Daylight |
| Aircraft 1 | |
| Make Model Name | B737-800 |
| Operating Under FAR Part | Part 121 |
| Flight Phase | Climb |
| Flight Plan | IFR |
| Person 1 | |
| Function | Captain Pilot Flying |
| Qualification | Flight Crew Air Transport Pilot (ATP) |
| Events | |
| Anomaly | ATC Issue All Types Deviation - Altitude Excursion From Assigned Altitude Inflight Event / Encounter Weather / Turbulence |
Narrative:
Level at FL380 on the western slopes of sierras we encountered a strong mountain wave. As the speed started to roll back I selected max continuous thrust. This didn't help much. I then called oak center for lower. I was told unable and to stand by. I then told them we would not be able to maintain FL380 and I started a slow descent 300 FPM to get the speed to increase. As I was doing this oak called back and gave us FL360. We descended 150 ft while waiting for the clearance. Total airspeed loss was approximately 35 KTS during the event.
Original NASA ASRS Text
Title: A B737-800 flight crew encountered a mountain wave and began descending to recover a 35 KTS airspeed loss while awaiting ATC descent clearance.
Narrative: Level at FL380 on the Western slopes of Sierras we encountered a strong mountain wave. As the speed started to roll back I selected max continuous thrust. This didn't help much. I then called OAK Center for lower. I was told unable and to stand by. I then told them we would not be able to maintain FL380 and I started a slow descent 300 FPM to get the speed to increase. As I was doing this OAK called back and gave us FL360. We descended 150 FT while waiting for the clearance. Total airspeed loss was approximately 35 KTS during the event.
Data retrieved from NASA's ASRS site as of July 2013 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.