Date: 202105
Local time of day: 1801-2400
Location: ZZZ.Airport, US
Flight conditions: VMC
Light: Dusk
Aircraft: B737-700
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Flight phase: Taxi
Reporter organization: Air Carrier
Reporter function: Captain; Pilot Flying
Reporter qualification: Flight Crew Instrument; Flight Crew Air Transport Pilot (ATP); Flight Crew Multiengine
Human factors: Situational Awareness; Communication Breakdown; Training / Qualification
Second reporter function: First Officer; Pilot Not Flying
Anomaly: Deviation / Discrepancy - Procedural FAR; Deviation / Discrepancy - Procedural Published Material / Policy
Detector: Person Flight Crew
When detected: Taxi
Result: Flight Crew Became Reoriented
Contributing factors: Human Factors; Procedure
Primary problem: Human Factors

Narrative: This was the second leg of an OE for the First Officer who was returning to the line after more than one year on leave. We had planned and briefed a Single Engine Taxi (SET). I asked the Pushback Crew to push the aircraft 'towards ZZZ' to better align us for SET Ops. As we were pushing; I noticed a Company aircraft on the adjacent gate was also getting ready to push and commented to the First Officer that we might have to start both engines to safely taxi away. I then realized we could make a left 270 to make our turn towards the east; to taxi to the planned runway. The Pushback Crew asked for me to set the brakes and I complied; then asked me to set the brakes as they were pulling away. This caused a chuckle from both he and I as he got jumbled with his scripted words. The First Officer had completed the #2 engine start and started his flow. He got to the Air Conditioning panel and asked if it was set correctly.I reached up and turned the #2 engine bleed on and commented that the pack was now being powered. Between the chuckle with the Pushback Crew and the First Officer query; I lost my focus and didn't notice the FO did not complete his flow and callout. I was also concerned with getting the aircraft moving in the left 270 before Company pushed. The FO called for taxi and we proceeded down CS and Mike. After being cleared onto Mike and seeing there was no line for Runway XX; I called for #1 engine to be started. The FO started it and did his After Start Flow; noticing and announcing that we hadn't set the flaps. I verified this; stopped the aircraft and commanded flaps 1; Before Taxi Checklist. These items were accomplished; we continued with normal operations and took off and flew to ZZZ1 without further incident.Don't get distracted during critical phases of flight; specifically when very specific cues are used to command flaps and run checklists.


Second narrative: During the Crew brief; and prior to pushing back in ZZZ; the Captain briefed a single-engine taxi (SET). The Captain requested from the Tug Operator that the pushback be angled toward the turnout direction; to facilitate an easier SET break away to begin taxi.  When the pushback was complete; we discussed whether or not to start the remaining #1 engine; and abandon the SET plan; because the Pushback Crew had not pushed the aircraft in the position instructed. Ultimately; we decided to request; from the Ramp Controller; a turn in the opposite direction and continue with the SET plan.  Being on the second leg of OE; and getting familiar with the switch positions of the pressurization panel; I had stopped my after start flow at that panel; to ask the Captain a question. Inadvertently and after that interruption; I neglected to continue the flow to its completion.  Subsequently; we began our taxi without setting the flaps; which helps to trigger the Before Taxi Checklist.  When we eventually started the #1 engine during taxi out; I noticed that the flaps had not been set; as I usually re-check the items on an after start flow.  We stopped the aircraft; set the flaps; and completed the Before Taxi Checklist.  The flight continued as normal.I think that getting further comfortable with the pressurization panel; and that particular flow; will increase situational awareness and become less of a distraction.


Synopsis: B737-700 flight crew reported confusion and communications problems during push back and taxi.