Date: 202007
Local time of day: 1201-1800
Location: ZZZ.Airport, US
Flight conditions: VMC
Aircraft: Commercial Fixed Wing
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Mission: Passenger
Flight phase: Parked
Reporter organization: Air Carrier
Reporter function: Pilot Flying; First Officer
Reporter qualification: Flight Crew Multiengine; Flight Crew Instrument; Flight Crew Air Transport Pilot (ATP)
Human factors: Situational Awareness; Distraction; Communication Breakdown
Second reporter function: Pilot Not Flying; Captain
Anomaly: Deviation / Discrepancy - Procedural Published Material / Policy; Ground Event / Encounter Other / Unknown
Detector: Person Flight Crew
When detected: Aircraft In Service At Gate
Result: Flight Crew FLC complied w / Automation / Advisory
Contributing factors: Environment - Non Weather Related; Human Factors
Primary problem: Human Factors

Narrative: I was assigned to Flight ABCD on Day 4 as a line check airman and was scheduled to give X line-checks over X days. Prior to this assignment; I was scheduled on Day 3 to give a first officer requal which was [a] one day trip. This assignment was canceled on Day 1 due to an aircraft substitution. On Day 2 training scheduling called and asked if I could train the same first officer on a different assignment. Even though this assignment was longer; I agreed to do the trip. ZZZ-ZZZ1-ZZZ on Day 3.First day Requal ZZZ-ZZZ1-ZZZSecond day I started pairing Flight ABCD. First leg was line-check ZZZ-ZZZ2; then sit for 5:30 hours; then another line-check ZZZ2-ZZZ3. Since this was mid-trip; I was not able to get any rest and had a long lunch off-site from the airport with a friend. After lunch I did a line-check ZZZ2-ZZZ3. By the time I reached my hotel; I was tired; ate dinner and went to bed early.Third day started with a scheduled deadhead to ZZZ3-ZZZ4. When arriving in ZZZ4 and showed up for my next leg; a line-check ZZZ4-ZZZ5; I learned the original Captain had called in sick and the new Captain did not need a line-check. I informed training scheduling that the scheduled Captain was no longer on the trip and I was told to deadhead in the back of the aircraft to ZZZ5. At some point on day 2 or 3; crew scheduling called to inform me there was an issue with First Officer on the last day of my pairing for Flight EFGH; and asked if I could do the line check from the first officer seat. In the interest of the operation; I agreed.Fourth day started with a late hotel shuttle. By the time I got my required [COVID] temperature check and took the train to gate it was 25 minutes prior to departure. There were issues with the gate agents in issuing the required jumpseat access card. This flight was a line-check ZZZ5-ZZZ6. When I arrived in ZZZ6; I received an email from training scheduling; telling me that the Captain for Flight EFGH had called in sick and they were looking for a new Captain who needed a line check. I then called training scheduling and told them; if they could not find a Captain who needed a line check; I would prefer to go back to ZZZ when I arrived in ZZZ3. I told them it had been a long few days and I was tired and wanted to get home. The scheduler told me they did not have a first officer and they would have to leave me on the trip as the flying first officer. She also stated whoever the Captain was on this leg; I would be giving them a line-check from the right seat.ZZZ6-ZZZ3 the Captain on this leg had not flown in several months and just came out of a landings class. While this crew did a good job and had a satisfactory line-check; I spent most of the flight and debrief going over new procedures and techniques. When I landed in ZZZ3; I called Captain X and left a voice mail and followed up with a text regarding our roles and duties for Flight EFGH. I informed him; who I was and that I would be giving him a line check the next morning while sitting in the right seat doing first officer duties. I went to the hotel and had a normal night's sleep.Fifth day Flight in question.I went to the airport early so I would have extra time reviewing first officer flows and preparing the flight deck. When I started to preflight on the [tablet]; the flight plan never pushed to my [tablet] and I had to call dispatch twice. It never pushed and I had to get the dispatcher to mark me fit for duty and manually download the flight plan. I was at the gate an hour prior to the flight.Captain X showed up about 15 mins later. We briefed and I explained my role as an LCA and I would be giving him a line check from the right seat and we agreed I would fly the leg.The flight was uneventful; Captain X did a good job and I gave him high marks for his line-check. His performance was better than most other captains I have observed on prior line-checks.After we landed in ZZZ; we arrived at Gate XXX and stopped the aircraft; I did my parking flow. I cannot remember whether or not  I heard Captain X call to shut down engine #1. Engine #2 was shut down during the single engine taxi to the gate.We ran the parking check list. During the check list the Captain said several times that one of the rampers was signaling to him and he could not understand what the ramper was trying to communicate.  This was a distraction that pulled us away from or normal duties and interrupted the checklist.  After the check list; I had to complete the line check form on the [tablet]; which is cumbersome to use. I did notice a noise coming from the cabin and my first thought was it was the new cleaning system and thought it was odd because the passenger door just opened. I looked at the engine gauges and I could not see them because the screens were already set low for the termination. The Captain had gotten up out of his seat and immediately heard the noise from the engine and saw the ramp supervisor. He told me the #1 engine was still running. I immediately shut is down and reran the entire parking check list; visually confirmed the fuel flow was zero.  Captain X and I debriefed this. I am unsure of the amount of time from setting the parking brake to shutting down the engine but estimate is was 2 mins. It should also be noted that this aircraft has a different style of fuel cutoff levers. They are not levers but knobs and visually are not a prominent in the off and on positions. From the time the parking brake was set; to discovering the engine running; I never left my seat. During this time; I was still performing my LCA duties and was double checking all my first officer duties were completed. I believe that even if Captain X had not caught our mistake; I would have caught it before I left my seat.There were numerous distractions. I have only flown 36 hours in 90 days and have not flown in the first officer's seat in over four months. The numerous scheduling changes added to the confusion. Furthermore; it was difficult to evaluate a Captain from the right seat while managing my first officer and line check airman duties.I'm certainly not trying to make excuses because the errors were definitely made between the both of us.  Regardless of the distractions; I need to remain vigilant and strictly adhere to SOP.  Proper checklist discipline is one of the most important tools we have to avoid threats which ultimately lead to an overall reduction of errors.  I will use this event as a discussion point about the importance of checklist discipline as well as other procedural threats we face in our operation; especially in the current environment where so many pilots are changing seats and aircraft.


Second narrative: After parking at the gate the number one engine was left running due to procedure; distractions; and checklist non compliance. The flight was conducted as a line check for myself. The FO position was flown by an LCA. The LCA was on his last day of 5 and I was flying a one day trip. (deadhead ZZZ ZZZ1 operate ZZZ1 ZZZ2) I got to sleep at approximately XA:30 pm and I woke at XG:00 am at home and was unable to get back to sleep. I drove to ZZZ; deadheaded to ZZZ1 and operated the ZZZ1 ZZZ2 leg of my trip. I did not feel fatigued when I arrived in ZZZ1. The flight from ZZZ1 to ZZZ2 was uneventful. After arriving at the gate; I set the parking brake; verified brake pressure normal; and called for the number one engine to be shutdown. I started my after landing flow when I noticed a ground personnel giving me the external power signal. I was confused as the jet-bridge was the not yet at the aircraft. I returned the signal thinking he wanted to know if we wanted ground power. I finished my after landing flow and called for the parking checklist. The checklist was started; and again; I noticed the ground personnel signaling. I noticed the ground power was plugged in. I switch the aircraft over to ground power and shutdown the APU. We finish the parking checklist. During the checklist; I verbalized; but did not verify Engine Start Levers....Cutoff. We did a quick flight debrief and I headed toward the cockpit exit to thank the passengers. I heard the engine and saw a ground personnel in the jetway. I immediately realized what had happened and turned back to the cockpit and called for the engine to be shutdown. We ran the parking checklist again and debriefed our mishap. I allowed myself to be distracted during a checklist and did not call for the checklist to be started from the beginning. A mistake in checklist discipline. I have flown approximately 9 hours over the past 4 months due to the COVID-19 epidemic. during my deadhead flight from ZZZ to ZZZ1 I reviewed the emergency and normal procedures in my flight manual. I should have put more emphasis on the checklist section. The Captain is responsible for all checklists being completed!In over XX years of flying I have never been so disappointed in my performance as a pilot. I pride myself in being professional and SAFE. As the current state of the airline industry and our Country as a whole is a huge distraction to everyday life; I must be more disciplined than ever...Verbalize; Verify; Crosscheck!I will try to be a better pilot and strive to achieve perfect checklist compliance. I will also brief other pilots on my error to increase the safety of our airline.


Synopsis: Air carrier flight crew reported they left an engine running after parking at the gate. They cited as contributing factors the failure to complete a checklist due to distraction.