Narrative:

After pushback and engine start; upon turning air conditioning packs on; acrid smoke began coming out of vents. Shut off packs and recirculating fan while simultaneously returning to gate. Once the packs were turned off the smoke stopped increasing. Deplaned normally without incident. Smoke appears to have come from a loss of the left hydraulic system.

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Original NASA ASRS Text

Title: MD-80 Captain reported smoke in the aircraft when packs were turned on after pushback. Flight returned to the gate.

Narrative: After pushback and engine start; upon turning air conditioning packs on; acrid smoke began coming out of vents. Shut off packs and recirculating fan while simultaneously returning to gate. Once the packs were turned off the smoke stopped increasing. Deplaned normally without incident. Smoke appears to have come from a loss of the left hydraulic system.

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.