Beechjet 400
Flight Crew Instrument; Flight Crew Multiengine; Flight Crew Air Transport Pilot (ATP); Flight Crew Flight Instructor
Flight Crew Last 90 Days 60; Flight Crew Total 2900; Flight Crew Type 33
Situational Awareness; Training / Qualification
ATC Issue All Types; Deviation - Altitude Undershoot; Deviation - Speed All Types; Deviation / Discrepancy - Procedural Clearance; Flight Deck / Cabin / Aircraft Event Other / Unknown
Air Traffic Control Issued New Clearance; Flight Crew Took Evasive Action; Flight Crew Requested ATC Assistance / Clarification
Aircraft; Human Factors
While flying enroute we requested a climb to FL410 to stay above weather along our route. However; the airplane recently transferred ownership so it was not RVSM approved. We advised ATC prior to our climb; and they cleared us to climb non RVSM to FL410. After we switched controllers a few times; Washington Center asked us to climb to FL430. While in the climb; we noticed our performance deteriorating as we approached the maximum ceiling for the aircraft (FL450). We constantly advised approach that we would need more time to make the climb; and they were fine with the slow climb. Upon reaching our cruise altitude of FL430; the airspeed began dropping and we were only climbing at 100 feet per minute. As we began to level off; the autopilot disengaged and we experienced stick shaker for the first indication of a stall. The pilot flying lowered the nose to prevent a stall; and the aircraft descended 800 feet in the recovery. At this point; we requested FL420 or FL410; but the controller denied it. When we requested a descent to FL280; the controller requested a turn 20 degrees left; but we couldn't turn very quickly with the imminent stall situation. Therefore; we took the turn slowly to be safe.Contributing Factors - the captain had never flown above Fl410 before and high altitude flight/stalls had never been discussed in any of his training. This was my first trip in the Beechjet since I completed my training. Almost all of my training was performed in a simulator below 10;000 feet at low speed flight. Not only was I nervous and overwhelmed with my first trip; but I didn't know what to expect.Actions - The captain noticed the stall indication and immediately reacted accordingly. As the PM; I notified ATC immediately.Inactions - both of us failed to realize that our poor climb performance would affect our ability to level off; maintain altitude; and cruise in turbulence at high altitude.
About 10 minutes later the controller asked us if we were able to climb to FL430. We responded that we 'needed a few more minutes at FL410'. Eventually we were asked to climb. Initially the aircraft climb was acceptable; but passing FL420 we were unable to maintain 500 fpm in the climb. As we were leveling at FL430 we encountered turbulence; the airspeed began decreasing; and a stall was imminent. I asked the non-flying pilot to advice ATC that we had to descend immediately due to inability to maintain airspeed and we would take vectors if necessary.Our airspeed was still not increasing rapidly so I initiated a very shallow banked turn. ATC asked why we weren't turning fast enough etc. we were given a number to call. Upon landing at our destination; I contacted the ARTCC manager as advised. He was very nice and explained that we needed to keep them apprised in the future if the aircraft could not perform as expected. He said everything was 'ok'.
Two corporate pilots with modest high altitude experience were asked to climb to FL430 for traffic. As they approached their cleared altitude their BE40 would not maintain airspeed nor climb and they had to be vectored off course for traffic and were cleared to descend. 7-800 feet were lost in the maneuver as the turn off course was completed with little bank as the stick shaker was active.