A Q400 master warning alerted the aft baggage door was not secured so the QRH was complied with. Dur...

Narrative:

We were in the final phase of the climb passing FL180 for FL190 when the aircraft's master warning system detected the aft baggage door was not secure. After complying with QRH procedures we contacted operations control and informed them of the situation. The aircraft was not losing pressure at this time. Initially we were given the option of returning to the departure airport or diverting. We chose to head for a nearby airport. With the exception of the indication of an open door everything else was normal until about 10 NM north of the airport. As we were descending through about 5;000 ft myself and the captain both heard a loud bang which was confirmed by the flight attendants who also reported a loud whistling noise. Around the same time we noticed a spike in cabin altitude as the door seal broke and the aircraft depressurized. Even though we were leveling at 4;000 ft at this point and pressure was not an issue we were worried as to what the position of the door was; so the captain declared an emergency. We asked for a straight-in; however; by the time ATC coordinated that it was easier to continue the downwind for 1R. We were cleared for the visual. Emergency services met the plane as we exited the runway. We shut down the #1 engine and they confirmed the aft cargo door handle was unsecured and the door open.

Original NASA ASRS Text

Title: A Q400 Master Warning alerted the aft baggage door was not secured so the QRH was complied with. During the diversion to a nearby airport the aft baggage door opened and the aircraft depressurized at 4;000 FT.

Narrative: We were in the final phase of the climb passing FL180 for FL190 when the aircraft's Master Warning system detected the aft baggage door was not secure. After complying with QRH procedures we contacted Operations Control and informed them of the situation. The aircraft was not losing pressure at this time. Initially we were given the option of returning to the departure airport or diverting. We chose to head for a nearby airport. With the exception of the indication of an open door everything else was normal until about 10 NM north of the airport. As we were descending through about 5;000 FT myself and the Captain both heard a loud bang which was confirmed by the flight attendants who also reported a loud whistling noise. Around the same time we noticed a spike in cabin altitude as the door seal broke and the aircraft depressurized. Even though we were leveling at 4;000 FT at this point and pressure was not an issue we were worried as to what the position of the door was; so the Captain declared an emergency. We asked for a straight-in; however; by the time ATC coordinated that it was easier to continue the downwind for 1R. We were cleared for the visual. Emergency services met the plane as we exited the runway. We shut down the #1 engine and they confirmed the aft cargo door handle was unsecured and the door open.

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.

Attributes
ACN	977677
Time
Date	201111
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	Q400
Operating Under FAR Part	Part 121
Flight Phase	Climb
Flight Plan	IFR
Component
Aircraft Component	Exterior Pax/Crew Door
Person 1
Function	Pilot Flying First Officer
Qualification	Flight Crew Commercial
Person 2
Function	Captain Pilot Not Flying
Qualification	Flight Crew Air Transport Pilot (ATP)
Events
Anomaly	Aircraft Equipment Problem Critical Deviation - Procedural Published Material / Policy

A Q400 master warning alerted the aft baggage door was not secured so the QRH was complied with. During the diversion to a nearby airport the aft baggage door opened and the aircraft depressurized at 4;000 ft.