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A CL65 at FL370 is forced to leave its assigned altitude without ATC clearance when the aircraft's stick shaker warns of an impending stall.
| Attributes | |
| ACN | 430078 |
| Time | |
| Date | 199901 |
| Day | Mon |
| Local Time Of Day | 1801 To 2400 |
| Place | |
| Locale Reference | navaid : psb.vortac |
| State Reference | PA |
| Altitude | msl bound lower : 36000 msl bound upper : 37000 |
| Environment | |
| Flight Conditions | IMC |
| Weather Elements | Thunderstorm Turbulence |
| Light | Night |
| Aircraft 1 | |
| Controlling Facilities | artcc : zny.artcc |
| Operator | common carrier : air carrier |
| Make Model Name | Challenger CL604 |
| Operating Under FAR Part | Part 121 |
| Navigation In Use | other vortac |
| Flight Phase | cruise : level descent : intermediate altitude |
| Flight Plan | IFR |
| Aircraft 2 | |
| Controlling Facilities | artcc : zny.artcc |
| Operator | common carrier : air carrier |
| Make Model Name | Commercial Fixed Wing |
| Operating Under FAR Part | Part 121 |
| Navigation In Use | other vortac |
| Flight Phase | cruise : level |
| Flight Plan | IFR |
| Person 1 | |
| Affiliation | company : air carrier |
| Function | flight crew : captain oversight : pic |
| Qualification | pilot : atp |
| Experience | flight time last 90 days : 240 flight time total : 13000 flight time type : 3600 |
| ASRS Report | 430078 |
| Person 2 | |
| Affiliation | company : air carrier |
| Function | flight crew : first officer |
| Qualification | pilot : instrument pilot : multi engine pilot : commercial |
| Events | |
| Anomaly | altitude deviation : excursion from assigned altitude conflict : airborne less severe non adherence : required legal separation non adherence : company policies non adherence : published procedure non adherence : clearance other anomaly |
| Independent Detector | atc equipment other atc equipment : mode c aircraft equipment other aircraft equipment : stick shaker other controllera other flight crewa |
| Resolutory Action | controller : issued advisory controller : issued new clearance flight crew : regained aircraft control flight crew : exited adverse environment |
| Miss Distance | vertical : 1000 |
| Supplementary | |
| Problem Areas | Flight Crew Human Performance Aircraft Environmental Factor Weather |
| Primary Problem | Flight Crew Human Performance |
| Air Traffic Incident | Pilot Deviation |
Narrative:
Performance charts were checked and climbed to FL370. WX at destination was strong thunderstorm, so dispatcher was called on radio #2. The aircraft stick shaker activated. Power was already at maximum so descent was initiated to FL360. ATC frequency was congested and a few hundred ft lost until authority/authorized to descend. Controller advised of traffic at FL350. We verified traffic on TCASII was still 1000 ft below. I think it is possible that the indicated static air temperature deviation increased while at altitude and/or turbulence may have caused stick shaker activation.
Original NASA ASRS Text
Title: A CL65 AT FL370 IS FORCED TO LEAVE ITS ASSIGNED ALT WITHOUT ATC CLRNC WHEN THE ACFT'S STICK SHAKER WARNS OF AN IMPENDING STALL.
Narrative: PERFORMANCE CHARTS WERE CHKED AND CLBED TO FL370. WX AT DEST WAS STRONG TSTM, SO DISPATCHER WAS CALLED ON RADIO #2. THE ACFT STICK SHAKER ACTIVATED. PWR WAS ALREADY AT MAX SO DSCNT WAS INITIATED TO FL360. ATC FREQ WAS CONGESTED AND A FEW HUNDRED FT LOST UNTIL AUTH TO DSND. CTLR ADVISED OF TFC AT FL350. WE VERIFIED TFC ON TCASII WAS STILL 1000 FT BELOW. I THINK IT IS POSSIBLE THAT THE INDICATED STATIC AIR TEMP DEV INCREASED WHILE AT ALT AND/OR TURB MAY HAVE CAUSED STICK SHAKER ACTIVATION.
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.