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A lear 35 flight crew experiences a temporary loss of aircraft control and an altitude excursion after running into a mountain wave west of the sierras at FL370 on frequency with ZOA, ca.
| Attributes | |
| ACN | 493390 |
| Time | |
| Date | 200011 |
| Day | Wed |
| Local Time Of Day | 1201 To 1800 |
| Place | |
| Locale Reference | atc facility : zoa.artcc |
| State Reference | CA |
| Altitude | msl bound lower : 37000 msl bound upper : 38500 |
| Environment | |
| Flight Conditions | IMC |
| Weather Elements | Turbulence other |
| Light | Daylight |
| Aircraft 1 | |
| Controlling Facilities | artcc : zoa.artcc tower : clt.tower |
| Operator | general aviation : corporate |
| Make Model Name | Learjet 35 |
| Operating Under FAR Part | Part 91 |
| Navigation In Use | other |
| Flight Phase | cruise : level |
| Flight Plan | IFR |
| Person 1 | |
| Affiliation | company : corporate |
| Function | flight crew : captain oversight : pic |
| Qualification | pilot : multi engine pilot : instrument pilot : cfi pilot : atp |
| Experience | flight time last 90 days : 125 flight time total : 8800 flight time type : 1000 |
| ASRS Report | 493390 |
| Person 2 | |
| Affiliation | company : corporate |
| Function | flight crew : first officer |
| Qualification | pilot : instrument pilot : commercial pilot : multi engine |
| Events | |
| Anomaly | altitude deviation : excursion from assigned altitude inflight encounter : turbulence non adherence : clearance other anomaly other anomaly other anomaly other |
| Independent Detector | other flight crewa |
| Resolutory Action | flight crew : regained aircraft control flight crew : exited adverse environment flight crew : returned to assigned altitude other |
| Supplementary | |
| Problem Areas | Weather |
| Primary Problem | Weather |
Narrative:
My copilot was flying this leg and had the autoplt engaged. We had just leveled FL370 and entered an area of moderate to severe turbulence associated with moderate mountain wave just west of the sierra nevadas. In a very short period of time, the aircraft accelerated to mmo, at which point the stick puller caused an immediate climb rate of 2000 FPM. I took over the airplane and reduced power to flight idle. The autoplt was disengaged and I held a nose level attitude, but not before we had climbed 1500 ft above assigned altitude. At that point, I notified center of both our altitude deviation and our encounter with some severe turbulence associated with some mountain wave. Fortunately, no aircraft were noted within .40 mi of our position on our TCASII.
Original NASA ASRS Text
Title: A LEAR 35 FLC EXPERIENCES A TEMPORARY LOSS OF ACFT CTL AND AN ALT EXCURSION AFTER RUNNING INTO A MOUNTAIN WAVE W OF THE SIERRAS AT FL370 ON FREQ WITH ZOA, CA.
Narrative: MY COPLT WAS FLYING THIS LEG AND HAD THE AUTOPLT ENGAGED. WE HAD JUST LEVELED FL370 AND ENTERED AN AREA OF MODERATE TO SEVERE TURB ASSOCIATED WITH MODERATE MOUNTAIN WAVE JUST W OF THE SIERRA NEVADAS. IN A VERY SHORT PERIOD OF TIME, THE ACFT ACCELERATED TO MMO, AT WHICH POINT THE STICK PULLER CAUSED AN IMMEDIATE CLB RATE OF 2000 FPM. I TOOK OVER THE AIRPLANE AND REDUCED PWR TO FLT IDLE. THE AUTOPLT WAS DISENGAGED AND I HELD A NOSE LEVEL ATTITUDE, BUT NOT BEFORE WE HAD CLBED 1500 FT ABOVE ASSIGNED ALT. AT THAT POINT, I NOTIFIED CTR OF BOTH OUR ALTDEV AND OUR ENCOUNTER WITH SOME SEVERE TURB ASSOCIATED WITH SOME MOUNTAIN WAVE. FORTUNATELY, NO ACFT WERE NOTED WITHIN .40 MI OF OUR POS ON OUR TCASII.
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.