Narrative:

While cruising at FL390, we were experiencing continuous light, occasional, moderate turbulence. In order to attempt to find smooth air, I requested FL430. According to the FMS, for our weight we could climb as high as FL445. Center asked if we could make the climb in 4 mins or less. After discussion (10 seconds), I confirmed we could do it. I set autoplt in vertical speed mode at 1200 FPM climb. We passed FL410 in less than 2 mins with no problems. By FL415, our airspeed started to decay rather rapidly. I reduced vertical speed to 700 FPM to try to stop airspeed decay. The airspeed loss slowed, but continued. Upon reaching FL430 (in 4 mins flat), speed had decayed to approximately .63 mach. I was unable to get the aircraft speed to increase at all. It was obvious that I had tried to comply with an ATC request that I should not have accepted. We were extremely close to getting the stick pusher. The only way to avoid it was to start a descent. We made several unanswered calls to center to advise our situation. When they responded, they wanted a 50 degree turn to the right for lower. I felt that any bank would exacerbate an already critical situation. We were advised of traffic at FL410, opposite direction. At that point we were at approximately FL424 and still descending. Finally, center got that other aircraft to turn. We watched him on TCASII and noted the closest we came was 5 - 5 1/2 mi horizontally and our altitude decayed to FL418. Once we were clear of traffic, center cleared us to FL350. I increased rate of descent and slowly our airspeed increased toward normal cruise speed. We explained what had happened to the controller who said 'no problem.' I have been plting jet aircraft almost exclusively for the past 12 yrs. The falcon 900EX is by far the most impressive performing aircraft I have ever flown. All of my flight time in the aircraft is in the last 9 months. I (know now) think I was a little overzealous in expecting the aircraft to be capable of sustaining such a rate of climb at such a high altitude. I had climbed and flown the aircraft at the same weight to FL430 without a problem. It was a serious lapse in judgement on my part for expecting too much performance. In retrospect, we normally try to maintain a 300-400 FPM rate of climb. My concern for providing the passenger a smooth ride combined with my desire to comply with an ATC request led us into a marginal situation. This is not the way I normally conduct a flight. The first officer, a co-captain, seemed to agree with my decisions. After discussing the outcome, he allowed that we had made a wrong decision. I had asked (not told, I guess) him to declare an emergency, but he commented that 'I think we're ok.' I told him later I felt he had usurped my captain's position with that of his being the flight department manager. After further discussion, it was decided that from here forward, whoever is acting as captain, if he decides it is appropriate to declare an emergency, it will be declared.

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Original NASA ASRS Text

Title: AN F900 CREW, ENCOUNTERING LIGHT TO OCCASIONAL MODERATE TURB AT FL390, REQUESTED FL430 AND ACCEPTED A 4 MIN RESTR TO GET THERE. ACFT PERFORMANCE DECLINED, LOWER REQUESTED.

Narrative: WHILE CRUISING AT FL390, WE WERE EXPERIENCING CONTINUOUS LIGHT, OCCASIONAL, MODERATE TURB. IN ORDER TO ATTEMPT TO FIND SMOOTH AIR, I REQUESTED FL430. ACCORDING TO THE FMS, FOR OUR WT WE COULD CLB AS HIGH AS FL445. CTR ASKED IF WE COULD MAKE THE CLB IN 4 MINS OR LESS. AFTER DISCUSSION (10 SECONDS), I CONFIRMED WE COULD DO IT. I SET AUTOPLT IN VERT SPD MODE AT 1200 FPM CLB. WE PASSED FL410 IN LESS THAN 2 MINS WITH NO PROBS. BY FL415, OUR AIRSPD STARTED TO DECAY RATHER RAPIDLY. I REDUCED VERT SPD TO 700 FPM TO TRY TO STOP AIRSPD DECAY. THE AIRSPD LOSS SLOWED, BUT CONTINUED. UPON REACHING FL430 (IN 4 MINS FLAT), SPD HAD DECAYED TO APPROX .63 MACH. I WAS UNABLE TO GET THE ACFT SPD TO INCREASE AT ALL. IT WAS OBVIOUS THAT I HAD TRIED TO COMPLY WITH AN ATC REQUEST THAT I SHOULD NOT HAVE ACCEPTED. WE WERE EXTREMELY CLOSE TO GETTING THE STICK PUSHER. THE ONLY WAY TO AVOID IT WAS TO START A DSCNT. WE MADE SEVERAL UNANSWERED CALLS TO CTR TO ADVISE OUR SIT. WHEN THEY RESPONDED, THEY WANTED A 50 DEG TURN TO THE R FOR LOWER. I FELT THAT ANY BANK WOULD EXACERBATE AN ALREADY CRITICAL SIT. WE WERE ADVISED OF TFC AT FL410, OPPOSITE DIRECTION. AT THAT POINT WE WERE AT APPROX FL424 AND STILL DSNDING. FINALLY, CTR GOT THAT OTHER ACFT TO TURN. WE WATCHED HIM ON TCASII AND NOTED THE CLOSEST WE CAME WAS 5 - 5 1/2 MI HORIZLY AND OUR ALT DECAYED TO FL418. ONCE WE WERE CLR OF TFC, CTR CLRED US TO FL350. I INCREASED RATE OF DSCNT AND SLOWLY OUR AIRSPD INCREASED TOWARD NORMAL CRUISE SPD. WE EXPLAINED WHAT HAD HAPPENED TO THE CTLR WHO SAID 'NO PROB.' I HAVE BEEN PLTING JET ACFT ALMOST EXCLUSIVELY FOR THE PAST 12 YRS. THE FALCON 900EX IS BY FAR THE MOST IMPRESSIVE PERFORMING ACFT I HAVE EVER FLOWN. ALL OF MY FLT TIME IN THE ACFT IS IN THE LAST 9 MONTHS. I (KNOW NOW) THINK I WAS A LITTLE OVERZEALOUS IN EXPECTING THE ACFT TO BE CAPABLE OF SUSTAINING SUCH A RATE OF CLB AT SUCH A HIGH ALT. I HAD CLBED AND FLOWN THE ACFT AT THE SAME WT TO FL430 WITHOUT A PROB. IT WAS A SERIOUS LAPSE IN JUDGEMENT ON MY PART FOR EXPECTING TOO MUCH PERFORMANCE. IN RETROSPECT, WE NORMALLY TRY TO MAINTAIN A 300-400 FPM RATE OF CLB. MY CONCERN FOR PROVIDING THE PAX A SMOOTH RIDE COMBINED WITH MY DESIRE TO COMPLY WITH AN ATC REQUEST LED US INTO A MARGINAL SIT. THIS IS NOT THE WAY I NORMALLY CONDUCT A FLT. THE FO, A CO-CAPT, SEEMED TO AGREE WITH MY DECISIONS. AFTER DISCUSSING THE OUTCOME, HE ALLOWED THAT WE HAD MADE A WRONG DECISION. I HAD ASKED (NOT TOLD, I GUESS) HIM TO DECLARE AN EMER, BUT HE COMMENTED THAT 'I THINK WE'RE OK.' I TOLD HIM LATER I FELT HE HAD USURPED MY CAPT'S POS WITH THAT OF HIS BEING THE FLT DEPT MGR. AFTER FURTHER DISCUSSION, IT WAS DECIDED THAT FROM HERE FORWARD, WHOEVER IS ACTING AS CAPT, IF HE DECIDES IT IS APPROPRIATE TO DECLARE AN EMER, IT WILL BE DECLARED.

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.