Date: 201605
Local time of day: 0601-1200
Location: ZZZ.Airport, US
Flight conditions: VMC
Light: Daylight
Aircraft: B737-700
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Mission: Passenger
Flight phase: Climb
Airspace: Class B ZZZ
ATC / advisory: TRACON ZZZ
Reporter organization: Air Carrier
Reporter function: Captain
Reporter qualification: Flight Crew Air Transport Pilot (ATP)
Second reporter function: First Officer
Anomaly: Aircraft Equipment Problem Less Severe
Detector: Automation Aircraft Other Automation; Person Flight Crew
When detected: In-flight
Result: Flight Crew Landed As Precaution; Flight Crew Landed in Emergency Condition; Flight Crew Returned To Departure Airport; General Maintenance Action
Contributing factors: Aircraft
Primary problem: Aircraft

Narrative: During preflight of the Cargo Fire panel; the 'DISCH' light did not illuminate. It also did not illuminate with the Master Light test switch. Dispatch; Maintenance and Contract Maintenance were notified. During troubleshooting; the 'AFT EXT' light stopped testing correctly and the 'AFT' Fire Alert illuminated accompanied by the fire bell. The alert occurred several times. The aircraft was subsequently returned to service per MELs which required Maintenance action. Shortly after takeoff; the 'AFT' Cargo Fire alerted accompanied by the fire bell. The alert/bell lasted approximately five seconds. The QRH was referenced. Due to the previous Maintenance on the control panel and the fact that the indications had returned to normal; the fire bottle was not discharged. [ATC was advised]; the Flight Attendants and Passengers were briefed; rescue support was requested; and [company] was advised of our return. After landing; the runway was cleared; APU was started; and engine number two was shutdown to allow Fire Crew access to the aft of the aircraft. No abnormalities were noted by the Fire Crew; and we continued to the gate. After parking procedures were accomplished; I inspected the aft cargo bin; which was empty. However; the Ramp Agent who opened the cargo bin reported 'smoke' when he first opened the hatch. The fire crew inspected the bin and found no heat sources or fire indications. Contract Maintenance inspected the bin and found nothing conclusive.The passengers seemed in good spirits during deplaning. The Flight Attendants were debriefed; and also seemed fine. Dispatch; Company Maintenance; and the Chief Pilot on Call were all contacted. An entry was made in the aircraft logbook. All crew members and support operations functioned well. However; during my post event duties; I was interrupted several times by phone calls. It is imperative that post event actions be handled correctly; to include interfacing with the passengers and crew and possibly the agents; Maintenance and Fire Crew. I understand the perceived needs of other offices to contact the crew but this must not interfere with the crew's performance of their duties.Equipment malfunctions will always occur. However; our post event procedures can be improved to include a single point of contact for the Crew. As I understand my responsibilities; I must contact Dispatch; Maintenance; and Scheduling. A call to the Chief Pilot on Call is desirable. A call to [the pilots' union] might also be warranted. A single point of contact could greatly streamline these responsibilities and eliminate some errors.


Second narrative: [Report narrative contained no additional information.]


Synopsis: B737-700 flight crew reported returning to departure airport after receiving an Aft Cargo Fire warning that turned out to be an apparent false warning.