Narrative:

Emergency pressurization valve opened twice in-flight for three to five seconds while at FL360 in cruise. This was accompanied by the emergency pressure annunciator illuminating. The valve closed on its own both times. We decided to request an altitude below FL250 just in case we ran into any other problems with the pressurization. ATC had some traffic below us; so we decided to declare an emergency to facilitate our descent. At no time did we bust an assigned altitude; however. The non flying pilot ran the checklists; communicated with ATC; the company and the passengers during this incident. We both decided the best course of action was to divert to an airport that was fifty miles directly in front of us. We did divert without breaking any sops or fars to the best of my knowledge. The descent; approach and landing all went normally after the initial events. We did execute a couple of delay turns that we coordinated with ATC to burn off fuel and avoid landing overweight. The aircraft needs to have this emergency pressure problem solved before returning to service. It is a repeat problem that has been written up on several occasions by several crews.

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Original NASA ASRS Text

Title: A C-560 diverted to a nearby airport when they encountered repeated uncommanded openings of the emergency pressure relief valve.

Narrative: Emergency Pressurization Valve opened twice in-flight for three to five seconds while at FL360 in cruise. This was accompanied by the Emergency Pressure annunciator illuminating. The valve closed on its own both times. We decided to request an altitude below FL250 just in case we ran into any other problems with the pressurization. ATC had some traffic below us; so we decided to declare an emergency to facilitate our descent. At no time did we bust an assigned altitude; however. The non flying pilot ran the checklists; communicated with ATC; the company and the passengers during this incident. We both decided the best course of action was to divert to an airport that was fifty miles directly in front of us. We did divert without breaking any SOPs or FARs to the best of my knowledge. The descent; approach and landing all went normally after the initial events. We did execute a couple of delay turns that we coordinated with ATC to burn off fuel and avoid landing overweight. The aircraft needs to have this emergency pressure problem solved before returning to service. It is a repeat problem that has been written up on several occasions by several crews.

Data retrieved from NASA's ASRS site as of April 2012 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.