1 hour connection in Newark

With separate bookings: just forget it!

Such long-haulers are often delayed, and not only do you have to clear immigration, customs and departures security, but also switch terminals.

Waste no time; re-book your connection immediately (make sure you don't pay the airport taxes twice for this, as you only have to pay them for the flight you actually go on)

As you'll be ground-side having cleared Immigration/Customs you'll need to get between terminals on the monorail and the clear the security line into Terminal C. It's that last bit that would really concern me, those security lines can be long. Also C itself long, you could have a bit of trek to the gate.

Given that you need to be at your departure gate some time before the scheduled departure that 55 min window is rather less, so I would consider 55 min to be unreasonably tight.

However, I'm very conservative when going through EWR, and in previous discussions on this kind of topics people who know how airlines operate have assured me that if the connection is scheduled then it's feasible. One positive factor is that the airlines know that there is some slack in scheduled arrival times, so on a typical day you may in reality have more than 55 min.

If this is a single booking with a single airline then I could assume that they will deal with any issue if I miss the connection, it would be hassle, but I'd get there in the end.

If this is two separate bookings then I would be concerned as the risk is entirely yours.

Let's break down what you'll have to do with some rough time estimates:

• Get off the plane and make your way to the FIS area - 15 minutes, depending on where you're sitting and how far the gate is
• Immigration+customs - 10 minutes (could be faster, but I've had lines to get out of the customs area at EWR even with Global Entry that could make it longer)
• Walk to AirTrain, ride to Terminal C, walk to security - 12 minutes
• Go through security, TSA Pre - 10 minutes (Could be much longer certainly, but 10 seems like a reasonable minimum unless the place is super-quiet)
• Walk to your gate - 10 minutes (Terminal C is big and we don't know where your gate is)
• Be at the gate 15 minutes before departure, or you could be denied boarding

We're at 62 minutes there, and I don't consider my time estimates to be greatly padded. It's certainly possible for everything to go your way and to make it to the gate before they finish boarding. It's also possible that your flight is a few minutes late or any one of these steps takes five minutes longer than planned, and then it's completely impossible. And since you've arranged your own connection with two separate tickets, you'll be on your own.

I would not book this if it was a single ticket (nor would UA sell such a connection), and I certainly wouldn't with two separate tickets.