Narrative:

I did depart ZZZ at or about XA00 CST. The flight was conducted under FAA part 91 rules and regulations. A current and complete WX briefing was obtained, and this flight was considered to be a completely safe and normal operation. If it was something else, the aircraft would not have departed. The aircraft's weight and balance was considered, and we were at least 1000 pounds under maximum gross weight. Advancing time-wise into this flight, at or about 30 mins after departure, mem ARTCC had cleared cessna citation direct to ZZZ1 to climb and maintain FL410. ZME advised me to be level at FL410 within 2 or 3 mins. At this time, I had the aircraft climbing at 1000 ft per min, and I was passing FL402. The aircraft had been climbing quite well, and I hadn't anticipated any less climb than 500 FPM, which would have put me level at FL410 at or less than the time required by ZME. Upon passing FL408, the aircraft started to slow in its climb, and the airspeed decelerated. I dropped the nose a little, and let the aircraft accelerate. I stopped climbing at FL410, and the airspeed continued to decelerate. Of course, my thoughts were, once the aircraft levels off the airspeed would pick up, and that would be that. At FL410, the aircraft kept decelerating, and I felt and heard a rumbling coming from the rear of the aircraft. At this time, I disengaged the autoplt and hand flew the plane, so I could feel it better. The angle of attack indicator confirmed my suspicion the aircraft was approaching a stall. I am an instructor and a check airman in the cessna citation aircraft for an FAA part 135 company, and have experienced this when I have been training other people. Upon seeing what was happening, I asked first officer to contact ZME. Frequency was quite congested with traffic. I had noticed that first officer was having trouble getting through to ZME. At this time, I told first officer that we needed to declare an emergency, because I could no longer maintain FL410. The rumble was getting louder, and the angle of attack indicator was getting closer to the stall point. At that time, I believe that I personally got on the radio and told ZME we needed to make a change, because we could not maintain FL410. We had the aircraft's TCASII operating, and the instrument advised us that no traffic was to the north of us. ZME advised us that he could not give us lower due to oncoming traffic at FL390. ZME gave us a turn to the north and gave us a lower altitude. The citation's nose was lowered and ZME advised us that the traffic was no longer a factor. I believed the maximum altitude loss was 400 ft low. ZME advised us to call them upon arrival. I talked to the ZME supervisor. The first thing out of his mouth was that I hit that warm front and the aircraft had lost some of its performance. He advised that he received some comments earlier that day about it. I told him what had happened, and he understood. He advised me that, due to the automatic detector that went off, he had to file a report. I told him that I understood, and that I was an air traffic controller in the military at one time, and I knew how the system worked. It was always my intention to maintain FL410, but the aircraft (due to entering the warm front) would not stay at the altitude. By no means did I mean to descend out of my altitude, but I did have to look at my priorities which were fly the aircraft, and keep the aircraft from stalling, avoid other traffic, and the terrain. Then I needed to tell the appropriate air traffic controller about the problem, or changes that needed to be made, to keep the flight as safe as possible. There is no doubt in my mind that the flight crew handled these 3 items as best as anyone could. We were cleared direct to destination, and ZME gave us the altitude we wanted, so we had no reason to turn or descend if we did not have to.

Related reports:

Google
 

Original NASA ASRS Text

Title: C560 CREW CLBED ACFT TOO HIGH FOR THE ACFT GROSS WT, GOT ON THE BACK SIDE OF THE PWR CURVE, AND WITH SLOWING AIRSPD, HAD TO DSND TO PREVENT A STALL IN ZME CLASS A.

Narrative: I DID DEPART ZZZ AT OR ABOUT XA00 CST. THE FLT WAS CONDUCTED UNDER FAA PART 91 RULES AND REGULATIONS. A CURRENT AND COMPLETE WX BRIEFING WAS OBTAINED, AND THIS FLT WAS CONSIDERED TO BE A COMPLETELY SAFE AND NORMAL OP. IF IT WAS SOMETHING ELSE, THE ACFT WOULD NOT HAVE DEPARTED. THE ACFT'S WT AND BAL WAS CONSIDERED, AND WE WERE AT LEAST 1000 LBS UNDER MAX GROSS WT. ADVANCING TIME-WISE INTO THIS FLT, AT OR ABOUT 30 MINS AFTER DEP, MEM ARTCC HAD CLRED CESSNA CITATION DIRECT TO ZZZ1 TO CLB AND MAINTAIN FL410. ZME ADVISED ME TO BE LEVEL AT FL410 WITHIN 2 OR 3 MINS. AT THIS TIME, I HAD THE ACFT CLBING AT 1000 FT PER MIN, AND I WAS PASSING FL402. THE ACFT HAD BEEN CLBING QUITE WELL, AND I HADN'T ANTICIPATED ANY LESS CLB THAN 500 FPM, WHICH WOULD HAVE PUT ME LEVEL AT FL410 AT OR LESS THAN THE TIME REQUIRED BY ZME. UPON PASSING FL408, THE ACFT STARTED TO SLOW IN ITS CLB, AND THE AIRSPD DECELERATED. I DROPPED THE NOSE A LITTLE, AND LET THE ACFT ACCELERATE. I STOPPED CLBING AT FL410, AND THE AIRSPD CONTINUED TO DECELERATE. OF COURSE, MY THOUGHTS WERE, ONCE THE ACFT LEVELS OFF THE AIRSPD WOULD PICK UP, AND THAT WOULD BE THAT. AT FL410, THE ACFT KEPT DECELERATING, AND I FELT AND HEARD A RUMBLING COMING FROM THE REAR OF THE ACFT. AT THIS TIME, I DISENGAGED THE AUTOPLT AND HAND FLEW THE PLANE, SO I COULD FEEL IT BETTER. THE ANGLE OF ATTACK INDICATOR CONFIRMED MY SUSPICION THE ACFT WAS APCHING A STALL. I AM AN INSTRUCTOR AND A CHK AIRMAN IN THE CESSNA CITATION ACFT FOR AN FAA PART 135 COMPANY, AND HAVE EXPERIENCED THIS WHEN I HAVE BEEN TRAINING OTHER PEOPLE. UPON SEEING WHAT WAS HAPPENING, I ASKED FO TO CONTACT ZME. FREQ WAS QUITE CONGESTED WITH TFC. I HAD NOTICED THAT FO WAS HAVING TROUBLE GETTING THROUGH TO ZME. AT THIS TIME, I TOLD FO THAT WE NEEDED TO DECLARE AN EMER, BECAUSE I COULD NO LONGER MAINTAIN FL410. THE RUMBLE WAS GETTING LOUDER, AND THE ANGLE OF ATTACK INDICATOR WAS GETTING CLOSER TO THE STALL POINT. AT THAT TIME, I BELIEVE THAT I PERSONALLY GOT ON THE RADIO AND TOLD ZME WE NEEDED TO MAKE A CHANGE, BECAUSE WE COULD NOT MAINTAIN FL410. WE HAD THE ACFT'S TCASII OPERATING, AND THE INST ADVISED US THAT NO TFC WAS TO THE N OF US. ZME ADVISED US THAT HE COULD NOT GIVE US LOWER DUE TO ONCOMING TFC AT FL390. ZME GAVE US A TURN TO THE N AND GAVE US A LOWER ALT. THE CITATION'S NOSE WAS LOWERED AND ZME ADVISED US THAT THE TFC WAS NO LONGER A FACTOR. I BELIEVED THE MAX ALT LOSS WAS 400 FT LOW. ZME ADVISED US TO CALL THEM UPON ARR. I TALKED TO THE ZME SUPVR. THE FIRST THING OUT OF HIS MOUTH WAS THAT I HIT THAT WARM FRONT AND THE ACFT HAD LOST SOME OF ITS PERFORMANCE. HE ADVISED THAT HE RECEIVED SOME COMMENTS EARLIER THAT DAY ABOUT IT. I TOLD HIM WHAT HAD HAPPENED, AND HE UNDERSTOOD. HE ADVISED ME THAT, DUE TO THE AUTOMATIC DETECTOR THAT WENT OFF, HE HAD TO FILE A RPT. I TOLD HIM THAT I UNDERSTOOD, AND THAT I WAS AN AIR TFC CTLR IN THE MIL AT ONE TIME, AND I KNEW HOW THE SYS WORKED. IT WAS ALWAYS MY INTENTION TO MAINTAIN FL410, BUT THE ACFT (DUE TO ENTERING THE WARM FRONT) WOULD NOT STAY AT THE ALT. BY NO MEANS DID I MEAN TO DSND OUT OF MY ALT, BUT I DID HAVE TO LOOK AT MY PRIORITIES WHICH WERE FLY THE ACFT, AND KEEP THE ACFT FROM STALLING, AVOID OTHER TFC, AND THE TERRAIN. THEN I NEEDED TO TELL THE APPROPRIATE AIR TFC CTLR ABOUT THE PROB, OR CHANGES THAT NEEDED TO BE MADE, TO KEEP THE FLT AS SAFE AS POSSIBLE. THERE IS NO DOUBT IN MY MIND THAT THE FLT CREW HANDLED THESE 3 ITEMS AS BEST AS ANYONE COULD. WE WERE CLRED DIRECT TO DEST, AND ZME GAVE US THE ALT WE WANTED, SO WE HAD NO REASON TO TURN OR DSND IF WE DID NOT HAVE TO.

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.