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B767 flight crew lost control of aircraft speed during mountain wave encounter resulting the aircraft exceeding vmo airspeed limitations.
| Attributes | |
| ACN | 535818 |
| Time | |
| Date | 200201 |
| Day | Sun |
| Local Time Of Day | 0601 To 1200 |
| Place | |
| Locale Reference | navaid : cim.vortac |
| State Reference | NM |
| Altitude | msl single value : 41000 |
| Environment | |
| Weather Elements | other |
| Light | Daylight |
| Aircraft 1 | |
| Controlling Facilities | artcc : zab.artcc |
| Operator | common carrier : air carrier |
| Make Model Name | B767 Undifferentiated or Other Model |
| Operating Under FAR Part | Part 121 |
| Navigation In Use | other |
| Flight Phase | cruise : level |
| Flight Plan | IFR |
| Person 1 | |
| Affiliation | company : air carrier |
| Function | flight crew : first officer |
| Experience | flight time last 90 days : 939 |
| ASRS Report | 535818 |
| Person 2 | |
| Affiliation | company : air carrier |
| Function | flight crew : captain oversight : pic |
| Qualification | pilot : atp |
| Experience | flight time last 90 days : 847 |
| ASRS Report | 536002 |
| Events | |
| Anomaly | inflight encounter : turbulence inflight encounter : weather non adherence : published procedure other anomaly |
| Independent Detector | aircraft equipment other aircraft equipment : airspeedindicators other flight crewa other flight crewb |
| Resolutory Action | controller : issued new clearance controller : provided flight assist flight crew : regained aircraft control flight crew : exited adverse environment |
| Consequence | other |
| Supplementary | |
| Problem Areas | Weather |
| Primary Problem | Weather |
Narrative:
Encountered severe mountain wave en route 25 NM wet of cim at FL410. Airspeed prior to encounter was mach .79/235 IAS. Airspeed decreased to approximately 210 IAS with thrust at maximum continuous power. Airspeed then reversed with aircraft accelerating to above vmo to approximately mach .87 with throttles at idle and spdbrakes fully deployed. Encounter reported to abq center and received clearance to descend to FL390. Oscillations continued with less severity and ride was smooth. Winds aloft at time of encounter was 280 degrees at 58 KTS. Dispatch and company maintenance were advised. Flight continued to ewr and ewr maintenance were debriefed.
Original NASA ASRS Text
Title: B767 FLC LOST CTL OF ACFT SPD DURING MOUNTAIN WAVE ENCOUNTER RESULTING THE ACFT EXCEEDING VMO AIRSPEED LIMITATIONS.
Narrative: ENCOUNTERED SEVERE MOUNTAIN WAVE ENRTE 25 NM WET OF CIM AT FL410. AIRSPD PRIOR TO ENCOUNTER WAS MACH .79/235 IAS. AIRSPD DECREASED TO APPROX 210 IAS WITH THRUST AT MAX CONTINUOUS PWR. AIRSPD THEN REVERSED WITH ACFT ACCELERATING TO ABOVE VMO TO APPROX MACH .87 WITH THROTTLES AT IDLE AND SPDBRAKES FULLY DEPLOYED. ENCOUNTER REPORTED TO ABQ CENTER AND RECEIVED CLRNC TO DESCEND TO FL390. OSCILLATIONS CONTINUED WITH LESS SEVERITY AND RIDE WAS SMOOTH. WINDS ALOFT AT TIME OF ENCOUNTER WAS 280 DEGS AT 58 KTS. DISPATCH AND COMPANY MAINT WERE ADVISED. FLT CONTINUED TO EWR AND EWR MAINT WERE DEBRIEFED.
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.