Citationjet (C525/C526) - CJ I / II / III / IV
Flight Crew Multiengine; Flight Crew Instrument; Flight Crew Flight Instructor; Flight Crew Air Transport Pilot (ATP)
Flight Crew Last 90 Days 66; Flight Crew Total 6553; Flight Crew Type 2017
Aircraft Equipment Problem Critical
Air Traffic Control Issued New Clearance; General Declared Emergency
Aircraft
While descending through FL250 the cabin altitude suddenly increased to 16;000 FT with a trend to continue climb; therefore; after using O2 we requested a descent to 15;000 FT and they asked if we intended to declare an emergency. We reported that we were ready to do so if necessary to receive a clearance to descend. ATC replied they declared the emergency for us and we were clear to descend to 15;000 FT and we initiated an emergency descent. While descending to 15;000 FT we were cleared to continue descent to 10;000 FT. Upon reaching 10;000 FT we discontinued the use of O2. There was no evidence of any structural damage that may have caused the problem and we addressed the cause of the pressurization failure to the outflow valve or the system's controller; therefore we requested to continue to destination which was estimated in 35 minutes.
CE525 Captain experiences loss of pressurization descending through FL250. Oxygen masks are donned until leveling at 10;000 feet and the flight continues to destination.