Transfer time help needed in LHR - LY to AA
 

I have two trips scheduled to TLV in the upcoming months. I have a question regarding the practicality on my return.
There is a LY flight tlv-lhr departing 9:05am-12:35 and connecting to AA #79 departing 2:20pm.
I hope the AA flight will be in business if that makes difference.
Is that enough time to connect? I imagine there is a terminal change involved and that requires going through security again?

the LHR connections planner is a good place to start which explains the process and if your flights are within the MCT (or not)

Will you have luggage? On one PNR? Some airlines are refusing to interline bags when on separate tickets and that could complicate your trip. Not sure if this applies to AA<>LY but something to bear in mind.

I will have luggage. The flight will sold as a AA flight on LY metal. There won't be any problem with interline.
I just don't want to stress the whole flight into lhr wondering if my connection was too tight... ☺

If it's above the MCT then you shouldn't have any problems. Thousands of people transit through LHR daily well within the MCT.

If your flight has a long delay it would be tighter but AA would rebook you.

Remember on arrival at T3 connections AA will want to do their passport / security question process / likely reissue your BP thing (see the very long thread on this on the AA board)

To answer one of the OP's direct questions, yes you will have to go through security. The UK government requires absolutely everyone flying out of a UK airport to go through UK security. The only people who don't have to go through security at LHR are those who are connecting off a UK domestic flight and staying within the same terminal (because they've already been through UK security and haven't mixed with uncleared passengers).