Narrative:

While cruising at FL230 on J150 approaching cyn VOR, we noticed a master warning cabin door annunciator. I executed the necessary memory action items that pertain to this potential emergency. The memory action is: all occupants seated with seatbelts fastened. This was accomplished. Next I contacted dispatch to advise them of the situation while the captain declared the emergency with ZNY and explained that we were going to divert to phl. This was a decision that both the captain and I concurred with. We then both agreed that acy was a better choice to divert to due to its close proximity and smaller, less congested airspace. We were given radar vectors and then we descended as soon as we were given clearance. The descent and before landing checklist were performed followed by a brief of the airport environment and approach for runway 4 in acy. Shortly before we started the visual approach, the captain requested emergency equipment. The landing was normal and safely uneventful (the passenger were briefed entirely.) to answer the question of what may have caused the cabin door annunciator to illuminate, I would have to say it was a faulty indication of a failed microswitch.

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Original NASA ASRS Text

Title: A BEECH 1900 IN CRUISE AT FL230 DECLARED AN EMER AND DIVERTED DUE TO A CABIN DOOR WARNING LIGHT CAUSED BY A FAILED MICROSWITCH.

Narrative: WHILE CRUISING AT FL230 ON J150 APCHING CYN VOR, WE NOTICED A MASTER WARNING CABIN DOOR ANNUNCIATOR. I EXECUTED THE NECESSARY MEMORY ACTION ITEMS THAT PERTAIN TO THIS POTENTIAL EMER. THE MEMORY ACTION IS: ALL OCCUPANTS SEATED WITH SEATBELTS FASTENED. THIS WAS ACCOMPLISHED. NEXT I CONTACTED DISPATCH TO ADVISE THEM OF THE SIT WHILE THE CAPT DECLARED THE EMER WITH ZNY AND EXPLAINED THAT WE WERE GOING TO DIVERT TO PHL. THIS WAS A DECISION THAT BOTH THE CAPT AND I CONCURRED WITH. WE THEN BOTH AGREED THAT ACY WAS A BETTER CHOICE TO DIVERT TO DUE TO ITS CLOSE PROX AND SMALLER, LESS CONGESTED AIRSPACE. WE WERE GIVEN RADAR VECTORS AND THEN WE DSNDED AS SOON AS WE WERE GIVEN CLRNC. THE DSCNT AND BEFORE LNDG CHKLIST WERE PERFORMED FOLLOWED BY A BRIEF OF THE ARPT ENVIRONMENT AND APCH FOR RWY 4 IN ACY. SHORTLY BEFORE WE STARTED THE VISUAL APCH, THE CAPT REQUESTED EMER EQUIP. THE LNDG WAS NORMAL AND SAFELY UNEVENTFUL (THE PAX WERE BRIEFED ENTIRELY.) TO ANSWER THE QUESTION OF WHAT MAY HAVE CAUSED THE CABIN DOOR ANNUNCIATOR TO ILLUMINATE, I WOULD HAVE TO SAY IT WAS A FAULTY INDICATION OF A FAILED MICROSWITCH.

Data retrieved from NASA's ASRS site as of July 2007 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.