Narrative:

At FL400 during the cruise checklist; noted hydraulic pressure on 'a' side at 20%. Notified ATC; declared an emergency; and diverted to [the nearest suitable airport]. Worked through the checklist and landed without incident.

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Original NASA ASRS Text

Title: CE750 experienced an 'A' system hydraulic system failure at FL400 and diverted to the nearest suitable airport after declaring an emergency.

Narrative: At FL400 during the cruise checklist; noted HYD pressure on 'A' side at 20%. Notified ATC; declared an emergency; and diverted to [the nearest suitable airport]. Worked through the checklist and landed without incident.

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.