Narrative:

Aircraft X; departed ZZZ normally and reached cruising altitude without incident. 30 minutes into the flight; we observed a louder than normal humming and vibration coming from below the flight deck. At about 1 hour into the flight; the humming and vibration tone would momentarily lower; as if an electric motor was struggling; followed shortly by an electric burning smell. The sound and smell would resolve in seconds. These episodes happened 3 times until it the tone of the hum dropped permanently; followed by much stronger and persistent electrical burning fumes. We donned oxygen masks; [advised ATC]; and informed ATC that we were diverting to ZZZ1. A minute later we received an ECAM caution for vent extract fault.ATC gave us a heading to fly and a descent towards ZZZ1. Pilot flying prepared for the approach while pilot monitoring performed smoke/fumes/avionics smoke QRH procedures. Pilot monitoring also performed overweight landing QRH.ZZZ1 tower cleared us to land [runway] xxl and we touched down and stopped on the runway without incident. We were inspected by crash fire rescue by thermal cameras to determine if we had a fire or other threat coming from the avionics bay. They reported there were a 'few hot spots' but nothing they deemed dangerous.we cleared the runway and proceeded normally to the gate.it was determined by ZZZ1 contract maintenance that the avionics bay extract fan had seized and was the source of the noise and fumes.there is a noticeable trend of MEL and nef items on these aircraft. These airplanes need more thorough maintenance checks and adequate time on the ground to find preventable failure points like this.

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Original NASA ASRS Text

Title: A319 Captain reported executing a diversion due to electrical burning smell accompanied by an apparent Avionics Exhaust Fan failure.

Narrative: Aircraft X; departed ZZZ normally and reached cruising altitude without incident. 30 minutes into the flight; we observed a louder than normal humming and vibration coming from below the flight deck. At about 1 hour into the flight; the humming and vibration tone would momentarily lower; as if an electric motor was struggling; followed shortly by an electric burning smell. The sound and smell would resolve in seconds. These episodes happened 3 times until it the tone of the hum dropped permanently; followed by much stronger and persistent electrical burning fumes. We donned oxygen masks; [advised ATC]; and informed ATC that we were diverting to ZZZ1. A minute later we received an ECAM caution for VENT EXTRACT FAULT.ATC gave us a heading to fly and a descent towards ZZZ1. Pilot Flying prepared for the approach while Pilot Monitoring performed Smoke/Fumes/Avionics Smoke QRH procedures. Pilot Monitoring also performed Overweight Landing QRH.ZZZ1 Tower cleared us to land [Runway] XXL and we touched down and stopped on the runway without incident. We were inspected by Crash Fire Rescue by thermal cameras to determine if we had a fire or other threat coming from the avionics bay. They reported there were a 'few hot spots' but nothing they deemed dangerous.We cleared the runway and proceeded normally to the gate.It was determined by ZZZ1 Contract Maintenance that the Avionics Bay Extract Fan had seized and was the source of the noise and fumes.There is a noticeable trend of MEL and NEF items on these aircraft. These airplanes need more thorough maintenance checks and adequate time on the ground to find preventable failure points like this.

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.