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CL65 at FL350, with ZMP, requested FL410. At FL410, experienced buffeting and required emergency descent.
| Attributes | |
| ACN | 567954 |
| Time | |
| Date | 200212 |
| Day | Fri |
| Local Time Of Day | 1801 To 2400 |
| Place | |
| Locale Reference | navaid : lnk.vortac |
| State Reference | MN |
| Altitude | msl single value : 41000 |
| Environment | |
| Flight Conditions | VMC |
| Light | Night |
| Aircraft 1 | |
| Controlling Facilities | artcc : zmp.artcc |
| Operator | common carrier : air carrier |
| Make Model Name | Regional Jet CL65, Undifferentiated or Other Model |
| Operating Under FAR Part | Part 121 |
| Navigation In Use | other |
| Flight Phase | cruise : level |
| Flight Plan | IFR |
| Aircraft 2 | |
| Controlling Facilities | artcc : zmp.artcc |
| Make Model Name | Any Unknown or Unlisted Aircraft Manufacturer |
| Flight Phase | cruise : level |
| Flight Plan | IFR |
| Person 1 | |
| Affiliation | company : air carrier |
| Function | flight crew : first officer |
| Qualification | pilot : atp |
| Experience | flight time last 90 days : 75 flight time total : 3250 flight time type : 145 |
| Person 2 | |
| Affiliation | company : air carrier |
| Function | flight crew : captain oversight : pic |
| Events | |
| Anomaly | altitude deviation : excursion from assigned altitude conflict : airborne critical non adherence : published procedure non adherence : far non adherence : company policies other anomaly |
| Independent Detector | other flight crewa |
| Resolutory Action | aircraft : automation overrode flight crew controller : issued new clearance flight crew : regained aircraft control flight crew : took precautionary avoidance action flight crew : declared emergency |
| Consequence | faa : reviewed incident with flight crew |
| Miss Distance | horizontal : 30000 vertical : 7 |
| Supplementary | |
| Problem Areas | Flight Crew Human Performance Aircraft |
| Primary Problem | Flight Crew Human Performance |
Narrative:
We were cruising at our flight planned altitude of FL370, and decided to climb to FL410. We consulted our step climb charts. Since outside air temperature was isa -5 degree C, and our initial climb weight was 40700 pounds, we decided we could maintain a climb rate of roughly 110 FPM at FL410. We received clearance to FL410, selected climb thrust in the FMS and were able to climb to FL410 at 500 FPM. We leveled off at mach .68-.69, but continued to lose airspeed. We requested a lower altitude and were told by ZMP that it would be another 5 mins due to traffic. We noticed traffic at FL390 on the TCASII display. Approximately 15 KTS above the low speed stall awareness raster, we noticed slight buffeting and requested a heading so we could descend away from traffic. ATC told us to turn right 20 degrees. At that point, the autoplt disconnected with the stick shaker as we were making the turn. I immediately notified ATC that we could not maintain altitude and that we needed to descend now. ATC stated that, 'if you want to descend now, you must declare an emergency.' we received a TCASII TA as we were descending. We had the traffic in sight and leveled off at FL397. ATC then asked what altitude we wanted, and we told them FL370. ATC then cleared us to FL370 and direct destination. After reviewing the flight sequence of events several times on my own, I believe what contributed to this incident was the flight crew's inaccurate interpretation of the CL65 step climb charts and failure to follow the profile spelled out in the step climb charts.
Original NASA ASRS Text
Title: CL65 AT FL350, WITH ZMP, REQUESTED FL410. AT FL410, EXPERIENCED BUFFETING AND REQUIRED EMER DSCNT.
Narrative: WE WERE CRUISING AT OUR FLT PLANNED ALT OF FL370, AND DECIDED TO CLB TO FL410. WE CONSULTED OUR STEP CLB CHARTS. SINCE OUTSIDE AIR TEMP WAS ISA -5 DEG C, AND OUR INITIAL CLB WT WAS 40700 LBS, WE DECIDED WE COULD MAINTAIN A CLB RATE OF ROUGHLY 110 FPM AT FL410. WE RECEIVED CLRNC TO FL410, SELECTED CLB THRUST IN THE FMS AND WERE ABLE TO CLB TO FL410 AT 500 FPM. WE LEVELED OFF AT MACH .68-.69, BUT CONTINUED TO LOSE AIRSPD. WE REQUESTED A LOWER ALT AND WERE TOLD BY ZMP THAT IT WOULD BE ANOTHER 5 MINS DUE TO TFC. WE NOTICED TFC AT FL390 ON THE TCASII DISPLAY. APPROX 15 KTS ABOVE THE LOW SPD STALL AWARENESS RASTER, WE NOTICED SLIGHT BUFFETING AND REQUESTED A HDG SO WE COULD DSND AWAY FROM TFC. ATC TOLD US TO TURN R 20 DEGS. AT THAT POINT, THE AUTOPLT DISCONNECTED WITH THE STICK SHAKER AS WE WERE MAKING THE TURN. I IMMEDIATELY NOTIFIED ATC THAT WE COULD NOT MAINTAIN ALT AND THAT WE NEEDED TO DSND NOW. ATC STATED THAT, 'IF YOU WANT TO DSND NOW, YOU MUST DECLARE AN EMER.' WE RECEIVED A TCASII TA AS WE WERE DSNDING. WE HAD THE TFC IN SIGHT AND LEVELED OFF AT FL397. ATC THEN ASKED WHAT ALT WE WANTED, AND WE TOLD THEM FL370. ATC THEN CLRED US TO FL370 AND DIRECT DEST. AFTER REVIEWING THE FLT SEQUENCE OF EVENTS SEVERAL TIMES ON MY OWN, I BELIEVE WHAT CONTRIBUTED TO THIS INCIDENT WAS THE FLC'S INACCURATE INTERP OF THE CL65 STEP CLB CHARTS AND FAILURE TO FOLLOW THE PROFILE SPELLED OUT IN THE STEP CLB CHARTS.
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.