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Near loss of aircraft control after stall warning activated by deteriorating airspeed which mandates and altitude excursion by a lear 45 at FL490 on frequency with ZOB, oh.
| Attributes | |
| ACN | 584601 |
| Time | |
| Date | 200305 |
| Day | Sun |
| Local Time Of Day | 0601 To 1200 |
| Place | |
| Locale Reference | atc facility : zob.artcc |
| State Reference | OH |
| Altitude | msl bound lower : 4700 msl bound upper : 4900 |
| Environment | |
| Flight Conditions | VMC |
| Weather Elements | Turbulence |
| Light | Daylight |
| Aircraft 1 | |
| Controlling Facilities | artcc : zob.artcc tower : bwi.tower |
| Operator | general aviation : corporate |
| Make Model Name | Learjet 45 |
| Operating Under FAR Part | Part 91 |
| Navigation In Use | other |
| Flight Phase | climbout : vacating altitude climbout : intermediate altitude cruise : level cruise : enroute altitude change |
| Flight Plan | IFR |
| Person 1 | |
| Affiliation | company : corporate |
| Function | flight crew : captain oversight : pic |
| Qualification | pilot : multi engine pilot : atp |
| Experience | flight time last 90 days : 105 flight time total : 10430 flight time type : 130 |
| ASRS Report | 584601 |
| Person 2 | |
| Affiliation | company : corporate |
| Function | flight crew : first officer |
| Events | |
| Anomaly | altitude deviation : excursion from assigned altitude non adherence : clearance non adherence other other anomaly other anomaly other anomaly other |
| Independent Detector | aircraft equipment other aircraft equipment : stall warning system other flight crewa other flight crewb |
| Resolutory Action | other |
| Supplementary | |
| Problem Areas | Flight Crew Human Performance Aircraft Weather |
| Primary Problem | Flight Crew Human Performance |
| Air Traffic Incident | Pilot Deviation |
Narrative:
We were cleared to climb to FL490. I was in the right seat. Upon leveling at FL490, the nose of the airplane was approximately 5 degrees above the horizon, the airspeed decayed until, at approximately mach .63, we heard the 'stall' warning and got the stick shaker. The left seat pilot lowered the nose to avoid the stall and I immediately requested lower (FL470) from ZOB. By the time the controller approved FL470, we had descended to approximately FL47.7. We had regained airspeed to about mach .68 by that time. The remainder of the flight was uneventful. My opinion is that we should have climbed at a shallower angle, thus saving airspeed, and I should have requested a block of altitude from FL470 to FL490. I also believe that light turbulence contributed some to the situation.
Original NASA ASRS Text
Title: NEAR LOSS OF ACFT CTL AFTER STALL WARNING ACTIVATED BY DETERIORATING AIRSPD WHICH MANDATES AND ALT EXCURSION BY A LEAR 45 AT FL490 ON FREQ WITH ZOB, OH.
Narrative: WE WERE CLRED TO CLB TO FL490. I WAS IN THE R SEAT. UPON LEVELING AT FL490, THE NOSE OF THE AIRPLANE WAS APPROX 5 DEGS ABOVE THE HORIZON, THE AIRSPD DECAYED UNTIL, AT APPROX MACH .63, WE HEARD THE 'STALL' WARNING AND GOT THE STICK SHAKER. THE L SEAT PLT LOWERED THE NOSE TO AVOID THE STALL AND I IMMEDIATELY REQUESTED LOWER (FL470) FROM ZOB. BY THE TIME THE CTLR APPROVED FL470, WE HAD DSNDED TO APPROX FL47.7. WE HAD REGAINED AIRSPD TO ABOUT MACH .68 BY THAT TIME. THE REMAINDER OF THE FLT WAS UNEVENTFUL. MY OPINION IS THAT WE SHOULD HAVE CLBED AT A SHALLOWER ANGLE, THUS SAVING AIRSPD, AND I SHOULD HAVE REQUESTED A BLOCK OF ALT FROM FL470 TO FL490. I ALSO BELIEVE THAT LIGHT TURB CONTRIBUTED SOME TO THE SIT.
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.