Narrative:

Enroute we experienced a muffled bang sound; followed by a loud whirling continuous noise like an electric motor that was failing. At the same time; there was also a small vibration. Shortly after; our #1 flight attendant called and said she heard a large bang by the 1 right (1R) door. After she hung up; we thought we had a possible aircraft structural problem that may cause a rapid decompression; and we asked for a lower altitude of 14;000 feet. Now the noise was accompanied by an acrid electrical smell. The captain and I got on oxygen and began the smoke/avionics smoke/fumes immediate action item checklist. I [informed ATC of our situation] and told them we want to divert. The #1 flight attendant called to say she smelled smoke; however when the captain tried to communicate with her through the oxygen mask microphone; she could not understand what I was saying. There was a loud feedback squeal in the speaker when he transmitted; and further complicating the situation; she could not understand what was being said from the poor quality of the oxygen mask microphone.after several attempts with the speaker causing a large feedback squeal; the captain took the mask off long enough to tell her to prepare for a landing and do a '30 second review;' he also made a quick announcement to the passengers to return to their seats; and turned the seatbelt sign back on. It was at this time he noticed that the smoke abated but the loud humming noise continued. With the smoke subsiding; he discontinued the smoke/fumes checklist after the first couple of steps. In hindsight; we should have continued beyond step 2 in the checklist; but the lack of communication distraction caused us to pause the checklist until it was no longer needed.I don't think it is possible to prevent the smoke/fumes events from occurring. But I feel [the airline] could drastically improve training to handle these events. Communicating with the captain while wearing the oxygen mask was difficult; and it was nearly impossible for him to communicate with the flight attendants. When discussing the abc's of threat and error management we are trained to communicate all threats and intentions. We were able to accomplish our tasks with a successful outcome; but it could have been much easier without the confusion from hindered communication.before I came to [this airline]; I spent 8 years in the training department at [another airline]. In addition to supervising all line and simulator check airmen I was responsible for all of our training curriculum. I was contacted by a captain who had a smoke event shortly after takeoff. At the time we trained to don the oxygen masks; turn on the intercom; and turn on the speaker. This resulted in both pilots hearing each other breathing through the masks over the speakers. The captain of the flight said it was nearly impossible to communicate with the first officer and air traffic control. We changed our procedures and produced a video that was shown during all initial; upgrade; and recurrent simulator training. After donning the oxygen masks we trained to put on your headset and use the intercom only when communicating with the other pilot to reduce feedback and background noise.I understand the company has agreed to revisit the smoke/fumes procedures. I feel the immediate actions for smoke/avionics smoke/fumes could be improved. I think the communication issue could be solved by training to put on your headset after the oxygen masks are on. I would add something along the lines of crew communication: establish to the immediate action checklist and even consider making the first 2-3 steps memory items. I would train these procedures during all initial and upgrade training and then revisit them annually.

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Original NASA ASRS Text

Title: A319 First Officer reported a muffled bang sound; followed by smoke in the cabin and difficulty communicating through the crew oxygen masks.

Narrative: Enroute we experienced a muffled bang sound; followed by a loud whirling continuous noise like an electric motor that was failing. At the same time; there was also a small vibration. Shortly after; our #1 Flight Attendant called and said she heard a large bang by the 1 Right (1R) door. After she hung up; we thought we had a possible aircraft structural problem that may cause a rapid decompression; and we asked for a lower altitude of 14;000 feet. Now the noise was accompanied by an acrid electrical smell. The Captain and I got on oxygen and began the smoke/avionics smoke/fumes immediate action item checklist. I [informed ATC of our situation] and told them we want to divert. The #1 Flight Attendant called to say she smelled smoke; however when the Captain tried to communicate with her through the oxygen mask microphone; she could not understand what I was saying. There was a loud feedback squeal in the speaker when he transmitted; and further complicating the situation; she could not understand what was being said from the poor quality of the oxygen mask microphone.After several attempts with the speaker causing a large feedback squeal; the Captain took the mask off long enough to tell her to prepare for a landing and do a '30 second review;' he also made a quick announcement to the passengers to return to their seats; and turned the seatbelt sign back on. It was at this time he noticed that the smoke abated but the loud humming noise continued. With the smoke subsiding; he discontinued the Smoke/Fumes checklist after the first couple of steps. In hindsight; we should have continued beyond step 2 in the checklist; but the lack of communication distraction caused us to pause the checklist until it was no longer needed.I don't think it is possible to prevent the smoke/fumes events from occurring. But I feel [the airline] could drastically improve training to handle these events. Communicating with the Captain while wearing the oxygen mask was difficult; and it was nearly impossible for him to communicate with the flight attendants. When discussing the ABC's of Threat and Error Management we are trained to communicate all threats and intentions. We were able to accomplish our tasks with a successful outcome; but it could have been much easier without the confusion from hindered communication.Before I came to [this airline]; I spent 8 years in the training department at [another airline]. In addition to supervising all Line and Simulator Check Airmen I was responsible for all of our training curriculum. I was contacted by a Captain who had a smoke event shortly after takeoff. At the time we trained to don the oxygen masks; turn on the intercom; and turn on the speaker. This resulted in both pilots hearing each other breathing through the masks over the speakers. The Captain of the flight said it was nearly impossible to communicate with the First Officer and Air Traffic Control. We changed our procedures and produced a video that was shown during all initial; upgrade; and recurrent simulator training. After donning the oxygen masks we trained to put on your headset and use the intercom only when communicating with the other pilot to reduce feedback and background noise.I understand the company has agreed to revisit the SMOKE/FUMES procedures. I feel the immediate actions for smoke/avionics smoke/fumes could be improved. I think the communication issue could be solved by training to put on your headset after the oxygen masks are on. I would add something along the lines of crew communication: establish to the Immediate Action checklist and even consider making the first 2-3 steps memory items. I would train these procedures during all initial and upgrade training and then revisit them annually.

Data retrieved from NASA's ASRS site and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.