Date: 201905
Local time of day: 0601-1200
Location: ZZZ.Airport, US
Flight conditions: VMC
Light: Daylight
Aircraft: ATR 42
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Mission: Passenger
Flight phase: Parked
Airspace: Class B ZZZ
ATC / advisory: Ramp ZZZ
Reporter organization: Air Carrier
Reporter function: First Officer
Reporter qualification: Flight Crew Air Transport Pilot (ATP); Flight Crew Instrument; Flight Crew Multiengine
Human factors: Confusion; Situational Awareness; Time Pressure
Second reporter function: Captain
Anomaly: Aircraft Equipment Problem Critical; Flight Deck / Cabin / Aircraft Event Smoke / Fire / Fumes / Odor; Ground Event / Encounter Other / Unknown
Detector: Person Flight Crew
When detected: Aircraft In Service At Gate
Result: General Evacuated
Contributing factors: Aircraft
Primary problem: Aircraft

Narrative: On visual approach into XL; Captain and I noticed pack #1 would fault intermittently and decided we would address the issue on the ground. After landing; we exited off XL and taxied to parking. We were instructed by Ramp to park at [the gate]. After 1 minute; Captain turned off Bleed #1 and shut down engine #1. We pulled into [the gate] and completed our parking checklist flows. At this time; Engine #1 was shut down and Engine #2 had just been placed in Hotel Mode. I looked down to grab my checklist and both Captain and I smelled a very foul odor. Seconds later the whole flight deck was engulfed in smoke. Captain instructed me to [advise ATC of our situation]; and I queried to verify that he wanted to declare. I then [advised Ramp of our situation]. Captain then let FA (Flight Attendant) know to deplane all the passengers immediately and that we had an emergency. We proceeded with the Smoke Memory Items and put on our oxygen masks. We continued with the On Ground Engine Fire; followed by the On Ground Emergency Exit Checklist. Once completed; we deplaned.


Second narrative: Acrid smell and smoke on flight deck during the parking checklist. Engine #1 was off during taxi-in after 1 minute. Engine #2 was running and I had just selected prop brake on. Pack #1 and #2 were running. Both pilots noticed acrid smell; then FO (First Officer) saw smoke filling cockpit. I instructed FO to [advise ATC] and she did on Ramp frequency. We donned oxygen masks. I pulled both engine fire handles. I contacted FA (Flight Attendant) and told her this was an emergency and get all passengers off the plane. CA (Captain) and FO ran Smoke memory items; Engine Fire On Ground checklist; and Emergency Evacuation checklists. I was unable to communicate the emergency to the Ramp. We were not communicating with Ramp on headsets; and ramp workers were busy chocking the aircraft; plugging in the GPU (Ground Power Unit); moving the valet cart; and opening the cargo and service doors. We do not have a dedicated frequency for our Dispatch; either; so it was very strange to be part-way through our emergency; only to have our flight deck door open up and have our Maintenance guy standing there wondering what the hell was happening as smoke rushed out the open door. It happened quickly and probably the only abnormality that somebody external of the aircraft might have noticed was the beacon on and engines off; emergency lights on; and two pilots with oxygen masks on. Fortunately; Inter-Island ramp took the emergency call and moved with it quickly; as we had no time to explain it or reconfirm our request for assistance. ARFF; private security; sheriff; [Company] management; [Company] Operations Manager; Maintenance; and other employees were quickly on the scene. The FA commented that she was unable to communicate to Ramp that the deplaning process; which was waiting on the hard stand for deplaning; was now an Emergency Evacuation. Ramp connected normally; unaware that an emergency was underway. The FA commented that she eventually got the attention of the Ramp to let them know we had a smoke emergency. Maintenance was unaware that an emergency was underway; so they boarded normally and entered the flight deck; only to be met by a cockpit full of smoke. The passengers were sort of aware as the FA was urging them to get off the aircraft.Suggestions:1. An agreed-upon way to immediately notify personnel around the noisy aircraft that something is wrong; we have an emergency; and we need help. Maybe go straight to pressing and holding the Maintenance horn? 2. I pulled off my headset to get my oxygen mask on. Imagine my frustration when I could not hear my FO or my FA. I don't remember pulling off my headset. I may have been in the process of removing it during the parking checklist and threw it aside. Regardless; I had my speaker; but unfortunately; it was either turned down or the system did not work correctly when I pulled the oxygen mask out of the holder and donned the mask. I couldn't communicate with anybody while on oxygen. My FO realized the issue was that I had removed my headset. We worked the memory items and checklists off oxygen as the smoke dissipated when Maintenance opened the flight deck door.


Synopsis: ATR 42 flight crew reported after shutdown dense smoke filled the aircraft and an evacuation was commanded.