Ce-525 captain reported diverting due to a pressurization event.

Attributes
ACN	1520966
Time
Date	201802
Local Time Of Day	0601-1200
Place
Locale Reference	ZZZ.ARTCC
State Reference	US
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Make Model Name	Citationjet (C525/C526) - CJ I / II / III / IV
Operating Under FAR Part	Part 91
Flight Phase	Cruise
Flight Plan	IFR
Component
Aircraft Component	Exterior Pax/Crew Door
Person 1
Function	Captain Pilot Flying
Qualification	Flight Crew Air Transport Pilot (ATP) Flight Crew Instrument Flight Crew Multiengine
Events
Anomaly	Aircraft Equipment Problem Critical

Narrative:

Door seal light illuminated. Followed procedure began descent out of FL40. During descent cabin depressurized; mask deployed; continued descent to 10000 diverted to XXX; uneventful landing.

Original NASA ASRS Text

Title: CE-525 Captain reported diverting due to a pressurization event.

Narrative: Door seal light illuminated. Followed procedure began descent out of FL40. During descent cabin depressurized; mask deployed; continued descent to 10000 diverted to XXX; uneventful landing.

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.