Citation I/SP (C501)
Flight Crew Air Transport Pilot (ATP); Flight Crew Multiengine
Flight Crew Last 90 Days 30; Flight Crew Total 14500; Flight Crew Type 2500
Aircraft Equipment Problem Critical
Air Traffic Control Issued New Clearance; Aircraft Equipment Problem Dissipated; Flight Crew Returned To Departure Airport; General Declared Emergency
Aircraft
While in cruise flight at FL430 I had a cabin pressurization failure resulting in a cabin climb rate of 7;000 FT/minute. I declared an emergency with Center and initiated a rapid descent. We put on our oxygen masks and notified ATC as to what was happening and received clearance to 17;000 FT. As we descended into the upper 20;000 FT range the cabin pressurization system resumed normal operation and started descending the cabin at a normal rate. Once the cabin dropped below 10;000 FT we discontinued use of oxygen and leveled at FL190 with ATC concurrence. All cabin pressurization systems had return to normal operation with a selected cabin altitude or 9;000 FT. I then requested and received ATC clearance for a return to the departure airport. The reasoning behind going back was the weather below us was not great with strong winds and rain and the departure airport weather was 6;500 overcast 8 mile visibility and 4 knot winds. As the aircraft was operating normally at that time and there were no other conflicts we returned at FL190; which kept us clear of the clouds and weather and the return flight was uneventful.
CE501 Captain reports a rapid loss of cabin pressurization at FL430. An emergency is declared and descent initiated until the upper twenty flight levels; when cabin pressurization returns to normal. The Captain elects to return to the departure airport at FL190 uneventfully.