CE501 captain reports a rapid loss of cabin pressurization at FL430. An emergency is declared and de...

Narrative:

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.

Original NASA ASRS Text

Title: 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.

Narrative: 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.

Data retrieved from NASA's ASRS site 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.

Attributes
ACN	1142545
Time
Date	201401
Local Time Of Day	1201-1800
Place
Locale Reference	ZZZ.ARTCC
State Reference	US
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Make Model Name	Citation I/SP (C501)
Operating Under FAR Part	Part 91
Flight Phase	Cruise
Flight Plan	IFR
Component
Aircraft Component	Pressurization Control System
Person 1
Function	Captain
Qualification	Flight Crew Air Transport Pilot (ATP) Flight Crew Multiengine
Experience	Flight Crew Last 90 Days 30 Flight Crew Total 14500 Flight Crew Type 2500
Events
Anomaly	Aircraft Equipment Problem Critical

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.