Date: 201310
Local time of day: 0601-1200
Location: ZZZ.ARTCC, US
Flight conditions: VMC
Aircraft: MD-83
Operating under: Part 121
Mission: Passenger
Flight phase: Cruise
ATC / advisory: Center ZZZ
Aircraft component: Cargo Compartment Fire/Overheat Warning
Component problem: Malfunctioning
Reporter organization: Air Carrier
Reporter function: Pilot Not Flying; Captain
Reporter qualification: Flight Crew Air Transport Pilot (ATP)
Second reporter function: First Officer; Pilot Flying
Anomaly: Aircraft Equipment Problem Less Severe; Deviation - Speed All Types
Detector: Automation Aircraft Other Automation; Person Flight Crew
When detected: In-flight
Result: Flight Crew Diverted; Flight Crew Landed in Emergency Condition; General Declared Emergency
Contributing factors: Aircraft
Primary problem: Aircraft

Narrative: Cruising at FL320; First Officer flying; when Aft Cargo Fire Warning alerted. Cargo Fire annunciator; Master Warning; and Aft Cargo indicator on the Cargo Fire Control panel all illuminated and the Cargo Fire horn sounded. I declared an emergency with ATC and requested immediate vectors to the nearest airport. First Officer began an emergency descent and I performed the QRH procedure for Aft Cargo Fire; including firing the first extinguisher. I briefed the Flight Attendant's of the situation and told them to prepare for an immediate landing including a possible evacuation. I then made a PA to the passengers. I asked ATC for a single frequency approach and got the CFR crews on frequency. I let them know we will stop on the runway and we need an inspection of the aft cargo bay. During this; the First Officer has been doing the emergency descent. He had exercised the Captain's emergency authority and kept the speed above 250 knots below 10;000 FT to expedite the descent. I rejoined him at about 5;000 FT on final for the VOR approach. I run a quick Before Landing checklist and he configures and continues the approach; breaking through a thin overcast at about 2;500 FT. We land and stop on the runway; I make a PA for the passengers to remain seated; but we prepare to the aircraft to possibly evacuate. The fire crews approach and inspect the aft cargo bay with infrared and visually and tell me there is no indication of fire. I let the passengers know the situation is over; and we taxied to the ramp. It took about 16 minutes from first warning to landing; the First Officer did a super job. I think overall we handled the situation well; except I could not find the button to silence the horn. We listened to the horn all the way down.


Second narrative: Enroute at FL320 we received an Aft Cargo Fire alert. I was the PF. Captain and I decided that ZZZ was the closest possible airport and declared emergency. I performed a rapid descent while Captain complied with QRH duties; cabin; Flight Attendant; ATC; and ARFF coordination. We performed the VOR approach and landing at ZZZ. ARFF found no fire. After clearance from ARRF; we taxied to terminal ramp and all passengers deplaned via aft air stair normally. No injuries to passengers or crew. It was a FALSE Fire Warning.


Synopsis: MD83 flight crew experiences an aft cargo fire warning at FL320 and diverts to the nearest suitable airport. An emergency descent is initiated; the QRH is complied with and a normal landing ensues 16 minutes after the initial warning. No actual fire existed.