A320 flight crew reported an issue with fumes in the cabin after engine start.

Attributes
ACN	1540181
Time
Date	201805
Local Time Of Day	1201-1800
Place
Locale Reference	ZZZ.Airport
State Reference	US
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Make Model Name	A320
Operating Under FAR Part	Part 121
Flight Phase	Taxi
Flight Plan	IFR
Component
Aircraft Component	Air Conditioning Distribution System
Person 1
Function	Pilot Flying Captain
Qualification	Flight Crew Air Transport Pilot (ATP) Flight Crew Instrument Flight Crew Multiengine
Experience	Flight Crew Last 90 Days 80 Flight Crew Total 13000 Flight Crew Type 7400
Person 2
Function	Pilot Not Flying First Officer
Qualification	Flight Crew Air Transport Pilot (ATP)
Experience	Flight Crew Total 4000
Events
Anomaly	Aircraft Equipment Problem Less Severe Flight Deck / Cabin / Aircraft Event Smoke / Fire / Fumes / Odor

Narrative:

After push back and engine start we configured for single engine and as we began our taxi the flight attendants called and said that the cabin was getting smoky. At that point; I could smell and see the smoke in the cockpit. I contacted ramp control and told them I needed the closest [gate]; and that we had a cabin and cockpit smoke event and needed to park and shut down immediately. Ramp cleared us to the gate; we parked; shut down and the passengers deplaned normally via door 1L and the jet bridge. The time from observed smoke to shutdown was less than 2 minutes.this was a new one for me. The smell was not quite electrical and the aircraft wasn't displaying any ecams; master warning or cautions. I recently finished A320 captain school and we spent a lot of time on the smoke/fumes checklist. The QRH smoke checklist doesn't apply because it's designed to get an airplane on the ground in a timely manner. We were already on the ground with a nearby gate available to us. Parking the airplane and deplaning the passengers via the jet bridge was the safest and quickest way to solve the problem.maintenance discovered a hydraulic fluid leak at the tail cone which was being ingested into the APU and then sent through the packs and into the cabin. I now know that burning hydraulic fluid has an acrid smell that's similar to an electrical smell.

Original NASA ASRS Text

Title: A320 flight crew reported an issue with fumes in the cabin after engine start.

Narrative: After push back and engine start we configured for single engine and as we began our taxi the Flight Attendants called and said that the cabin was getting smoky. At that point; I could smell and see the smoke in the cockpit. I contacted Ramp Control and told them I needed the closest [gate]; and that we had a cabin and cockpit smoke event and needed to park and shut down immediately. Ramp cleared us to the gate; we parked; shut down and the passengers deplaned normally via door 1L and the jet bridge. The time from observed smoke to shutdown was less than 2 minutes.This was a new one for me. The smell was not quite electrical and the aircraft wasn't displaying any ECAMs; Master Warning or Cautions. I recently finished A320 Captain school and we spent a lot of time on the Smoke/Fumes checklist. The QRH Smoke checklist doesn't apply because it's designed to get an airplane on the ground in a timely manner. We were already on the ground with a nearby gate available to us. Parking the airplane and deplaning the passengers via the jet bridge was the safest and quickest way to solve the problem.Maintenance discovered a hydraulic fluid leak at the tail cone which was being ingested into the APU and then sent through the packs and into the cabin. I now know that burning hydraulic fluid has an acrid smell that's similar to an electrical smell.

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.