I am looking at a flight from Rome to Chicago which has a 80 minute connection time to change planes in Heathrow. This is on a single reservation code. Is this realistic (and if not why would the airline even schedule this?) and if I were to miss my flight because I couldnt get to the 2nd leg, would the airline be responsible for getting me on a flight to Chicago? Thank you.
Answer to the 2nd question : YES. and EU261 compensation rights as well (they still exist in post Brexit UK).
Answer to the 1st, uhhmmm. Single reservation code is good, it means you can do an airside transfer and miss most of the things that would hold you up - even if the planes use different terminals. And you wouldn't need ETA. If the 1st leg is ontime it's easy. But if that was delayed we have to start asking about checked bags, they might have to wait for a later flight
This is completely possible. You simply need to keep moving. It is easiest if you transfer within the same terminal, but not impossible even if you have to transfer terminals. I've done this type of thing with transferring terminals and been through security in 45 minutes or less.
The key thing is to follow the the purple flight connections signs and know which terminal your next flight is taking off from. Also, you will go through security again. Make sure any liquids you picked up after security for your first flight are discarded.
We had a 75 minute transfer time last fall and made it with time to spare. As Carol mentioned, keep moving. Follow signs, don’t stop at the restroom. ;-)
You scan your second boarding pass to get through the screening for the airside transfer.
Since it's on one ticket, it will be easy.
When you get to Heathrow, follow the Flight Connections signs. If your transfer is in the same terminal, you will be routed to security (everyone has to go through security unless arriving from another UK airport) but it won't take long. From there onto your gate.
If you have to change terminals, you will follow the Flight Connections signs to a bus that will take you airside to your next terminal. You will go through security there.
Make sure you have the boarding pass for your flight out of Heathrow before you arrive. This will save time. (You should get it when you get your boarding pass for your flight out of Rome.) You will need to show it for the connection.
If you have a checked bag, it will automatically be transferred to your next flight.
No need to deal with immigration, customs or getting an ETA.
If you miss your connection due to no fault of your own, the airline is responsible for getting you on the next "available" flight at no extra charge to you. In fact, depending on the length of the delay you could be entitled to a food voucher, hotel voucher and even compensation. ("Available" does not mean the next flight. It means the next flight with available seats. They are not going to bump someone to allocate you.)
Whatever you do, don't follow the crowd to immigration. Follow the purple "Flight Connections" signs.