Date: 201907
Local time of day: 0601-1200
Location: ZZZ.Airport, US
Aircraft: B737 Undifferentiated or Other Model
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Mission: Passenger
Flight phase: Parked
Reporter organization: Air Carrier
Reporter function: First Officer; Pilot Not Flying
Reporter qualification: Flight Crew Air Transport Pilot (ATP); Flight Crew Instrument; Flight Crew Multiengine
Human factors: Distraction; Situational Awareness; Training / Qualification
Anomaly: Deviation / Discrepancy - Procedural Clearance; Deviation / Discrepancy - Procedural Published Material / Policy
Detector: Person Flight Crew
When detected: Pre-flight
Result: General None Reported / Taken
Contributing factors: Chart Or Publication; Human Factors; Company Policy
Primary problem: Human Factors

Narrative: This route ZZZ-ANC was new to me. At the gate; as I was familiarizing myself the paperwork it seemed that our routing was to take us quite far off the shoreline. I asked the Captain; who has been here over [XX] years; if this was an ETOPS flight; as it was not clear to me from the paperwork. He told me that it was not and said; 'Business as usual.' When I pointed out that as we got closer to Alaska; it appeared that we would be over 200 miles off the shore; he reiterated that it was not an ETOPS flight. I believed him.I looked through the paperwork for HF frequencies and satisfied that I didn't see them I convince myself that this was not an ETOPS flight. Once we were in route; I still had a feeling that we were missing something. When I pulled up the airspace segments on my WSI app; I realized with horror that indeed we would be entering oceanic airspace. When I pointed this out to the Captain; he was surprised. But he offered no solution to our conundrum.I asked the Captain if we should have had a master paper flight plan on board. He said that he didn't think so. I spent the next few minutes reading through my manuals and discovered that indeed; this flight was ETOPS; and as a result we needed a master paper flight plan. He said he was pretty sure that the HowGozIt sent through the printer would be sufficient. I pointed out in the manual where it said that that could be used as an addendum to the master paper flight plan. He disagreed and said we would be fine.By this time we were rapidly approaching oceanic airspace; and I was able to log on to KZAK before we crossed the fix. It was at that point the Vancouver Center told us that radar service was terminated and to contact AIRINC. I made a HF contact with San Francisco radio as we were crossing the fix; and received confirmation that our CPDLC logon was successful. Our SELCAL check was also successful.Because we did not have a paper flight plan; I used both sides of the HowGozIt to document all of the required oceanic position reporting information.The flight proceeded normally and as Pilot Monitoring I was able to cross all the T's and dot all the I's. However; I am embarrassed that even after inquiring with the Captain about this flight's ETOPS status; it took me so long to figure out. I can assure you that I spent much of the remainder of the flight reading over some of the things in my manuals that I had missed in my career at this airline so far. I erroneously relied on an extremely senior Captain to ensure that we were properly equipped and briefed for this flight. Suffice it to say that I am thankful I listened to that nagging feeling in my gut; persisted rooting around in my manuals; confirmed for us both the ETOPS status; and managed to get all of the CPDLC logon and position reporting handled in the nick of time. Unfortunately; once we blocked in and I handed the paperwork to the Captain for him to file as per usual with ETOPS flights; he tossed the HowGozIt (I.e. our Master Flight Plan) into the trash.There were a few giveaways that this flight was an ETOPS route. Unfortunately for a couple hours I missed all of them. One of the concerns I have was that nowhere were any HF frequencies published. That would have been a dead giveaway for me about the oceanic airspace. This is not the first time I have flown with this particular Captain; who is quite nonchalant about paperwork and briefings. I know better than to rely on him 100% for accuracy in answering my questions. I can assure you that in the future I will be better prepared when a route is new to me; and I have learned a lot more about a number of things thanks to my diving into the manuals today.




Synopsis: First Officer reported not being prepared for an ETOPS flight and conferring with Captain about correcting the situation.