Date: 201411
Local time of day: 1201-1800
Location: ZZZ.Airport, US
Aircraft: Regional Jet 900 (CRJ900)
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Flight phase: Parked
Aircraft component: Turbine Engine
Component problem: Improperly Operated
Reporter organization: Air Carrier
Reporter function: Captain
Reporter qualification: Flight Crew Air Transport Pilot (ATP)
Human factors: Confusion; Distraction; Situational Awareness; Communication Breakdown
Second reporter function: Other / Unknown
Anomaly: Aircraft Equipment Problem Critical; Deviation / Discrepancy - Procedural Published Material / Policy; Flight Deck / Cabin / Aircraft Event Other / Unknown
Detector: Person Flight Crew
When detected: Aircraft In Service At Gate
Result: Flight Crew Overcame Equipment Problem
Contributing factors: Aircraft; Human Factors
Primary problem: Human Factors

Narrative: We arrived and as I was shutting the engines down the ground power which had been applied to the aircraft after the first engine was shut down turned off. Because the APU was not running; I got out of my seat to yell out the door for the ground crew to re-establish the power. As I got out of my seat; the First Officer was still in his seat. I said I would be right back. As I looked out the aircraft door I saw the ground crew working on the power and turned back into the plane; never actually leaving the aircraft. I then saw there were no longer any passengers on board and decided to blow my nose in the forward lavatory real quick while the First Officer (FO) was up front and they were putting power back on. As I walked into the lav my FO and I must have crossed paths as he headed to the back; and the cockpit was empty for about 20-30 Seconds until I got out of the lav and back into the flight deck. I then got into my chair and shut the engine down uneventfully.Better communication with my FO to stay put until I get back would do the trick. He thought I was coming back up instead I needed a kleenex right away and stepped into the forward LAV.


Second narrative: I was a dead heading crew member. The flight was uneventful and landed on time with no issues on taxi in. While at the gate I waited until all the passengers had deplaned before exiting myself. As I exited the flight I met my first officer; also dead heading; standing just outside the door; waiting on his bag. I made mention to him that the engine was still running and was wondering why it had not been shut down well after block in at the gate. This is when the he pointed out to me that there was no one in the flight deck! I stepped back into the airplane and only saw one pilot who was in the back of the plane retrieving his bag from the overhead. I did not see the other pilot; however; I believe he was in the forward lav. Unsure of what else to do I stepped into the flight deck and sat down at the FO's station and started to assess the situation. The parking break was set with the right engine running; however; all the hydraulic pumps had been shut off. I restarted the [number] 2/3 hydraulic pumps to make sure the brakes were fully charged with pressure and then was trying to figure out if I could start the APU. Shortly after one of the crew showed up and then the other at the flight deck door. We then had a discussion as to why the aircraft had an empty flight deck sitting on a snow covered ramp with an engine running and no hydraulic pumps on. The only answer I got was that the parking break was on. I got the feeling that the crew assumed that this would be enough. I have a very big issue with this as one; the flight deck door should not be opened until both engines are shut down. The airport had been hammered with lake effect snow for three days at this time and the ramp was covered in snow. Now we have an engine running; still productions thrust; with no one monitoring; on a slippery surface. Lastly; the crew stated that they were close to the flight deck and could have taken action if necessary. My question is how could you be close enough to take action if some random person; ME; could walk back off the jet way; where there were still passengers standing and waiting for bags; and take a seat in the flight deck with an engine running? Once they returned to the flight deck I traded places with the captain. I then exited the aircraft; got my bags; and headed for the van.


Synopsis: Two distinctly different takes on how an engine was left running on a CRJ-900 with no crewmember in the cockpit.  Fortunately the outcome was benign but; nonetheless; embarrassing.