Date: 202012
Local time of day: 0601-1200
Location: ZZZ.Airport, US
Aircraft: Embraer Jet Undifferentiated or Other Model
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Mission: Passenger
Flight phase: Taxi
Reporter organization: Air Carrier
Reporter function: Captain; Pilot Flying
Reporter qualification: Flight Crew Multiengine; Flight Crew Instrument; Flight Crew Air Transport Pilot (ATP)
Anomaly: Aircraft Equipment Problem Less Severe; Flight Deck / Cabin / Aircraft Event Smoke / Fire / Fumes / Odor
Detector: Person Flight Attendant; Person Flight Crew
When detected: Taxi
Result: Air Traffic Control Provided Assistance; Aircraft Equipment Problem Dissipated; Flight Crew Returned To Gate; Flight Crew Overcame Equipment Problem; Flight Crew Requested ATC Assistance / Clarification; General Maintenance Action; General Flight Cancelled / Delayed
Contributing factors: Aircraft
Primary problem: Aircraft

Narrative: During push back from gate we started engine number 2 and disconnected from the pushback tug normally. We then noticed a faint burning smell in the cockpit that was present for only a moment. During this time we were positioned directly in front of a vehicle access road and there were multiple trucks driving in front of the aircraft. The First Officer and I discussed the smell and determined that due to the smell only being present for a short moment we were confident that it came from the vehicles near the aircraft. We then continued to taxi making a right turn on Taxiway Bravo. While taxiing; we received a call from the Flight Attendant. She told us that the back of the cabin was a little foggy. At this point I had two indications of a possible fire on board the aircraft; so I immediately contacted ZZZ ramp control and Requested Priority Handling and advised them that we had smoke in the cabin of the aircraft and needed to return to the gate. Ramp control cleared us to do a 180 degree turn and taxi to the gate and advised us that the rescue services were on their way. After making a 180 degree turn to get the aircraft heading back towards the gate; I then called the Flight Attendant back. I asked her if she had any updates on the situation with the smoke. She advised me that it was now mostly dissipated and that she had checked the lavatory and the cargo compartment and there was no evidence of smoke in either location. She also noted that she did not notice a smell of any sort during the time the smoke was primarily present. We spoke about the conditions of the passengers and she stated that the cabin was relatively calm and the passengers were doing just fine. I informed her that we would be returning to the gate for an expeditious deplaning. The First Officer and I discussed whether to perform the smoke fire or fumes memory action item but determined that it was not necessary due to the absence of smoke in the cockpit and due to the knowledge that the smoke in the cabin was dissipating. We then continued with the smoke fire or fumes checklist. The checklist had us push out both the re-circulation fan and the Gasper fan switches; and at this point a personnel from fire crash rescue started marshaling us into the gate. In order to return to the gate as quickly as possible to deplane the passengers; I made the decision to discontinue the checklist. To eliminate further potential sources of contaminated air entering the aircraft; I took it upon myself to shut off pack number 2 and the APU bleed at this time. Passenger number 1 was already off. We parked at the gate and performed a shut down checklist. We had the passengers deplane the aircraft using the mobile stairs at the gate. I don't recall the exact number of passengers we had on board but I believe it was less than 10; so deplaning was very quick. To ensure that the aircraft was not powered while emergency services personnel checked for the location of the source of the smoke; we immediately terminated the aircraft. EMS was present to ask each passenger of their condition and I was told that no one had any issue including the crew. Finally; I contacted Dispatch to inform them of the situation; and entered a discrepancy in the maintenance logbook.




Synopsis: Air Carrier Captain reported a 'burning smell' in the flight deck during taxi-out resulting in a return to the gate.