A310 captain reports a loud bang climbing through FL180 followed by an ECAM and overhead of a min eq...

Narrative:

During climb out around 18;000 feet we heard a large bang that shook the aircraft. We had no other abnormal indications but this was not normal and very concerning. We were not experiencing any turbulence and the bang was too large for something falling like a coffee pot. Within a few minutes we had a fire indication on the ECAM and overhead [indication] of a min equipment bay fire. I declared an emergency and immediately requested a lower altitude and a vector to the airport. We complied with the ECAM and did not notice any actual smoke. One in the descent the warning went out. We made a normal landing. The equipment and tower said they saw no fire indication from the aircraft so we continued the taxi to the ramp with the equipment with us. After block in all fire indications returned and did not go out. But again there appeared to be no actual fire on the aircraft and we have no idea what the bang and vibration was but due to concern about structural integrity we made a normal non aggressive approach and landing but returned immediately.

Original NASA ASRS Text

Title: A310 Captain reports a loud bang climbing through FL180 followed by an ECAM and overhead of a Min Equipment Bay Fire. ECAM is complied with and flight returns to departure airport. During descent the warning goes out but after landing and parking the warning returns. No real fire is detected.

Narrative: During climb out around 18;000 feet we heard a large bang that shook the aircraft. We had no other abnormal indications but this was not normal and very concerning. We were not experiencing any turbulence and the bang was too large for something falling like a coffee pot. Within a few minutes we had a fire indication on the ECAM and overhead [indication] of a Min Equipment Bay Fire. I declared an emergency and immediately requested a lower altitude and a vector to the airport. We complied with the ECAM and did not notice any actual smoke. One in the descent the warning went out. We made a normal landing. The equipment and Tower said they saw no fire indication from the aircraft so we continued the taxi to the ramp with the equipment with us. After block in all fire indications returned and did not go out. But again there appeared to be no actual fire on the aircraft and we have no idea what the bang and vibration was but due to concern about structural integrity we made a normal non aggressive approach and landing but returned immediately.

Data retrieved from NASA's ASRS site as of July 2013 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	1119583
Time
Date	201310
Local Time Of Day	0601-1200
Place
Locale Reference	ZZZZ.ARTCC
State Reference	FO
Aircraft 1
Make Model Name	A310
Operating Under FAR Part	Part 121
Flight Phase	Climb
Flight Plan	IFR
Component
Aircraft Component	Fire/Overheat Warning
Person 1
Function	Captain Pilot Flying
Qualification	Flight Crew Air Transport Pilot (ATP)
Events
Anomaly	Aircraft Equipment Problem Less Severe Flight Deck / Cabin / Aircraft Event Smoke / Fire / Fumes / Odor

A310 captain reports a loud bang climbing through FL180 followed by an ECAM and overhead of a min equipment bay fire. ECAM is complied with and flight returns to departure airport. During descent the warning goes out but after landing and parking the warning returns. No real fire is detected.