Originally Posted by
airmarc
I am flying MIA-LHR-HAM next week. This is 2 separate itineraries meaning MIA-LHR is on one ticket with AA, and then the onwards leg was booked with BA. I have 2 hours connection time and not checking a bag. Will I be able to stay airside and simply switch terminals (assuming I can check in at a connections counter or obtain my boarding pass online for the BA flight)
You can stay airside, but you will have to switch terminals and go through LHR security.
Your AA flight will very likely land in T3 and your BA flight will likely leave from T5.
Here's the drill. You land and follow the crowd down the concourse. Look for purple "Flight Connections" signs. Follow those purple signs that direct you to T5. That will take you to a bus waiting area. Get on the bus then get off at T5.
Upon arrival in T5, go up the escalator and again follow the purple signs to Flight Connections. Here is the place where you will get your new boarding pass. (Either that or download the BA app and get a mobile boarding pass.) Next is Flight Conformance. Someone will check your boarding pass, then send you up an escalator to LHR T5 Security, where you will go through the full security check. Unless you have heavy clunky shoes (avoid), you can keep your shoes on, but laptops, tables, Kindles, 3-1-1 liquids, etc, all come out of the bag.
After Security, you go into the main lounge area. They do not announce gates until they are ready to open the gate to departing passengers. In other words, you can't just go to your gate and wait there. Find a place in the departure lounge where you can watch the TV monitors and wait for your flight's gate to be announced, then make your way to the gate. Don't dawdle. They expect people to go directly to the gate once it's announced.
If you have extra time, you might want to walk around T5 to acquaint yourself with the layout before your flight gate is announced on the TV monitors.
Some flights leave from the two other T5 terminals, namely T5B and T5C. Usually they announce that on the TV monitor so you can make your way to T5B or T5C then wait there for the gate assignment. If you have to go to T5B or T5C, you will take a mini-train. The elevator to the T5B and T5C mini-train is on the south side of the terminal, clearly marked. Ask someone if you are unsure.
Note that the mini-train trip is one-way. You can't just get on the train to go sightseeing, then come back to T5A. When the mini-train gets to its destination, they check to see the train is free of passengers before letting the next group on. This way they isolate the arrivals from the departures.
When it's time to go back home, you'll do the same thing in reverse. Land at T5, follow the purple Flight Connection signs to the bus to T3, then go through LHR T3 security, then wait in the departure lounge.