A310
Flight Crew Air Transport Pilot (ATP)
Aircraft Equipment Problem Less Severe; Flight Deck / Cabin / Aircraft Event Smoke / Fire / Fumes / Odor
Aircraft Equipment Problem Dissipated; Flight Crew Landed As Precaution; Flight Crew Returned To Departure Airport; General Declared Emergency
Aircraft
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.
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.