Date: 202111
Local time of day: 1201-1800
Location: ZZZ.ARTCC, US
Flight conditions: IMC
Aircraft: Commercial Fixed Wing
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Mission: Passenger
Flight phase: Cruise
Airspace: Class A ZZZ
Aircraft component: Toilet Smoke; Overheat; Fire Detectors & Warning
Component problem: Malfunctioning
Reporter organization: Air Carrier
Reporter function: Pilot Not Flying; First Officer
Human factors: Distraction; Other / Unknown; Situational Awareness; Time Pressure; Troubleshooting; Workload; Confusion
Second reporter function: Pilot Not Flying; First Officer
Anomaly: Aircraft Equipment Problem Critical; Deviation / Discrepancy - Procedural Weight And Balance; Deviation / Discrepancy - Procedural Published Material / Policy; Flight Deck / Cabin / Aircraft Event Smoke / Fire / Fumes / Odor
Detector: Automation Aircraft Other Automation; Person Flight Crew
When detected: In-flight
Result: Air Traffic Control Provided Assistance; Flight Crew FLC complied w / Automation / Advisory; Flight Crew Diverted; Flight Crew Landed in Emergency Condition; Flight Crew Requested ATC Assistance / Clarification; General Evacuated
Contributing factors: Aircraft
Primary problem: Aircraft

Narrative: Approximately 70nm SE of ZZZ at FL340 we received a bag smoke EICAS alarm. We proceeded with the instructions of manual. After reviewing the manual; we followed with the QRH. We asked the FA (Flight Attendant) to please check the lavatory eye hole to determine if she saw any indication of an active fire. She called us to inform us that the lavatory was occupied. She called back several minutes later to indicate that she cannot see anything in there and that she heard a 'loud pop'. We informed her what was occurring and that we were diverting to ZZZ1 with around 15 minutes left. The bag smoke EICAS alert extinguished then reappeared. This led the Captain to believe that the fire had reappeared and was not contained by the extinguisher. He discussed with me the need of a possible evacuation. He stated he wanted to proceed with one after clearing the runway and I informed ATC of said event. We informed the FA of this and told her how much time left till landing and which exits to not open.I noticed that we were going to be overweight on landing and I proceeded with said overweight QRH card. The landing was smooth and less than 100 FPM on touchdown. Upon landing and exiting the runway; we rang her and informed her [to evacuate] and she proceeded with the evacuation. We then proceeded with the ground evacuation checklist the Captain worked with the [authorities] and I helped keep the passengers together with the fire crew and the FA. We then got everyone into the fire station at [taxiway] 1 on XXR. The events that unfolded were a direct result of a Bag Smoke EICAS alarm with no direct determination able to be made if there was an active fire in the baggage compartment.Possible system adjustment to have a different EICAS warning due to the 3 different possibilities of why a flight crew could receive a BAG SMOKE warning.


Second narrative: Approximately 70nm SE of ZZZ at FL340 we received a bag smoke alarm. We proceeded with the instructions of the manual. After reviewing the manual we followed with the QRH. We asked the FA (Flight Attendant) to please check the lavatory eye hole to determine if she saw any indication of an active fire. She called us to inform us that the lavatory was occupied. She called back several minutes later to indicate that she cannot see anything in there and that she heard a loud pop. We informed her what was occurring and that we were diverting to ZZZ1 with around 15 minutes left. During the subsequent high stress sudden turn of events and during the decent checklist; I noticed that we were going to have an overweight landing. I followed the QRH overweight checklist. I pulled up my EFB and noticed that I had downloaded the [wrong] Landing app instead of the [correct] one. This was just noticed yesterday as the Captain on the previous flights inputted the speeds every flight so I never had a need to open my app up. I notified the Captain and pulled out the back up QRH book for landing speeds and put them in. This disrupted my descent checklist and I do not remember if we finished the descent checklist past 'Landing Data/Speeds'. However; when I told the passengers that we were diverting to ZZZ1 I asked the FA to prepare for landing; so I do remember completing the checklist tasks but do not remember verbally finishing the checklist. This also causes concern for me as I remember being told to expect ILS XXL for the approach. We could pick up any course guidance and when we ask ATC about the ILS we were told it was OTS (Out of Service). We then switched to the ILS XXR last minute with a vector to join. As PM (Pilot Monitoring); I set up the flight instruments and radios for the Captain so that he could focus on the approach and flying the aircraft. Due to the last minute change of runway and we were carrying extra speed to expedite so that he could 'get on the ground as quick as possible due to a possible cargo compartment fire' I do not remember completing the before landing checklist. I remember inputting flaps 9 for him before joining the ILS XXL course and while I was programming the last minute change of runway to XXR he lowered the gear and then he asked for Flaps 22. I made a mental note that the final aircraft configuration was set up for landing but do not remember verbally accomplishing the before landing checklist. Two checklists not possibly verbally finished; aircraft speed below 1;000 ft. AGL.I believe the CRM fell apart once I noticed that my EFB had the incorrect landing data app and I had to stop my checklist to get the correct speeds from the QRH book for an overweight landing. We were a [priority] aircraft with a possible cargo compartment fire and then we were given a last minute change of runway assignment. This compounded the task saturation and I had to get caught back up with minutes left in the flight. The Captain had to step in for me to help configure the aircraft for landing while I was busy setting up for the approach.Always remember that during high stress events that you need to keep a calm demeanor; think and communicate clearly. Always revert back to training and make sure that the aircraft is in a positive state of control. Make sure that checklists are being completed as they are there to help make sure everything is being done correctly while stress is compounding.


Synopsis: Air Carrier Pilot Crew received an ECIAS Baggage Fire Warning. The pilots were unable to confirm a fire; diverted; and landed in an overweight condition.