Date: 202001
Local time of day: 1201-1800
Location: ZZZZ.Airport, FO
Flight conditions: Marginal
Light: Dusk
Aircraft: Regional Jet 900 (CRJ900)
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Mission: Passenger
Flight phase: Climb
Airspace: Class B ZZZZ
Aircraft component: Indicating and Warning - Landing Gear
Component problem: Malfunctioning
Reporter organization: Air Carrier
Reporter function: First Officer; Pilot Not Flying
Reporter qualification: Flight Crew Instrument; Flight Crew Multiengine; Flight Crew Air Transport Pilot (ATP)
Second reporter function: Captain; Pilot Flying
Anomaly: Aircraft Equipment Problem Critical; Deviation / Discrepancy - Procedural Published Material / Policy; Inflight Event / Encounter Weather / Turbulence
Detector: Person Flight Crew
When detected: In-flight
Result: Air Traffic Control Provided Assistance; Flight Crew Returned To Departure Airport; Flight Crew Landed in Emergency Condition; General Flight Cancelled / Delayed; General Maintenance Action
Contributing factors: Aircraft
Primary problem: Aircraft

Narrative: Everything was normal until [the] takeoff phase of the flight. It was a snowy day which required de-icing. We completed all the checklists and procedures for takeoff. We were cleared for takeoff. The Captain was the pilot flying and he applied T/O thrust. We accelerated normally and became airborne. About 10 seconds after retracting the gear; 'BRAKE OVHT (Overheat)' warning message displayed on EICAS and BTMS (Brake Temperature Monitoring System) red for Right Inboard. I called it and the Captain then said 'I have the radios; BRAKE OVHT emergency checklist.' The checklist led us to the QRH and QRH instructed us to lower the landing gear. After lowering the landing gear the temperature decreased all the way to within the specified green range. Then the QRH led us to put the gear back up and continue flight if no further indications occurred. However; when we retracted the gear again; the same BTMS temperature started increasing rapidly. The Captain called gear down; and I put the gear down and this action brought the temperature down again. At that point the Captain advised ATC due to possible fire and we leveled off at 5;000 feet. When we ran the QRH again the QRH led us to 'land nearest suitable airport.' We advised ATC that we needed about 15 minutes and vectors to stay close to the airport and completed After Takeoff checklist. The Captain transferred the flight controls to me and communicated with flight attendants for potential fire and Dispatch. In the meantime I loaded FMS and then briefed the approach to be flown. Then the Captain took the controls back; we ran the descent and Approach checklists. Initiated the approach and came to a complete stop on the runway after a fairly smooth landing and completing After Landing Shutdown checks; we requested ARFF (Aircraft Rescue and Fire Fighting). After fire rescue verified there was no indication of fire we requested to be towed to the gate and be escorted by fire rescue. We completed the flight safely at the gate and Maintenance personnel met us at the aircraft.The Mechanic told us that it was a BTMS sensor malfunction.


Second narrative: We received a BRAKE OVHT warning message soon after take off once the landing gear was fully retracted. I was the pilot flying and and we waited until 1;000 feet and I asked the FO to run the Emergency Checklist for BRAKE OVHT; and took over the radios. Once we completed the QRH including the notes in the QRH we were not 100% sure if this was a sensor error as it did not meet the criteria described in the QRH note. As a result we completed the QRH and this resulted in the QRH telling us to land at the nearest suitable airport. At that point in time ZZZZ was the nearest suitable airport. Additionally I suspected a heat source somewhere near the landing gear since the indication only came on every time the gear was up. We read through the checklist one more time to make sure we did not miss anything. After that we advised ATC and asked for delayed vectors to keep us close to the airport. I had a conversation with my FO to make a plan of action. I then gave him the flight controls so that I could loop the Dispatcher. I also had asked the FA to prepare for a red level incident and keep a look out for smoke or fumes near the middle of the cabin. I explained the situation and told them that I cannot be 100% sure if it is the sensor which is malfunctioning or if there is something else that's causing the Brake OVHT. I knew in the back of my mind that it had to be a bad sensor since we had just taken off from a snow covered airport; at the same time the other symptoms suggested that it may be something else which the QRH may not have accounted for. We made the decision to land based on this and also QRH. Everything was done in about 10 minutes and we were ready for an intentional overweight landing. I briefed the FO that during touch down I will be reducing my Vertical rate of descent to below 200 FPM; so we don't break apart. We also briefed and coordinated with the fire trucks that we will use minimum braking and stop near the end of the runway. The fire command chief got on the radio and inspected the aircraft after we landed and shut down our engines. We were given the all clear of no fire or hot brakes. We then contacted the company to get permission to be towed to the gate. Ops sent out a tug and we were taken to [the] gate in ZZZZ. A firetruck followed us. Once we got to the gate and we inspected the aircraft further and I thanked the fire chief for helping out. We proceeded with Maintenance; Dispatch and Fleet Manager's guidance from that point on.The mechanic advised us that it could be faulty sensors/wiring or the BTMS itself could be faulty.


Synopsis: CRJ-900 flight crew reported a malfunctioning brake temperature monitoring system sensor caused multiple brake overheat EICAS messages; requiring an air turn back.