Commercial Fixed Wing
Flight Crew Multiengine; Flight Crew Instrument; Flight Crew Air Transport Pilot (ATP)
Flight Crew Last 90 Days 174; Flight Crew Type 174
Situational Awareness
Deviation / Discrepancy - Procedural Published Material / Policy; Ground Event / Encounter Weather / Turbulence; Ground Event / Encounter Ground Equipment Issue
General None Reported / Taken
Weather; Human Factors
We finished the first leg of three on the last day of a three-day trip. We pulled into the gate at LAS with a scheduled plane swap. After completing the Parking Checklist and other post-flight duties; I cleared the FO to head out while I stayed with the aircraft while passengers deplaned. Ground power was connected initially but air was not. As deplaning commenced; I asked the agent to call for ground air. It was 106F OAT and I was concerned about cabin temp. I understood from the agent that the aircraft would be on the ground for some time. After all passengers were off; I went outside and asked Ramp to connect ground air. A few minutes later one of the guys came to the cockpit and informed me that ground air was inop. In the meantime; one of the new FAs (flight attendants) came onboard saying she came down early because the terminal was very crowded. As the situation progressed I decided to leave the APU on for cabin cooling; informed the FA and agent and went on to my new aircraft. At the time I didn't give it a second thought. It wasn't until I got to the new aircraft; finished preflight duties and had a few minutes to reflect that I realized my error. Sick feeling. I told the FO that I would be back and hustled back to the previous gate to remedy my mistake. Probably 30 minutes or so had elapsed since I had left it. By the time I got back to the gate The new crew was onboard and passengers were boarding.I must say that I didn't feel any type of particular time pressure or any major distraction. I'm not sure why my thought process went so awry. While this situation is not common; I'm sure it's not unheard of and I should know better than to leave the APU running and Terminating Checklist incomplete. I certainly could have stayed with the aircraft until the new Crew arrived.I am sure that I hadn't reviewed FOM in some time so unless I'm the only one who has messed up this way; adding that to our training profile may raise awareness to this issue and prevent someone else from making the same mistake.
Air carrier Captain reported they forgot to complete the terminating checklist.