I've read a bit about similar situations but am still looking for advice.

PIT>ORD 6:19pm to 7:19pm terminal 3 (Average delay about 10-15 minutes)
ORD>LHR on BA departs 8:35pm terminal 5 (Average delay over 20 minutes?)

This was booked for me over the phone by an Explat agent, only noticed past the 24 hour mark. It seems way too tight based on the thread.

2 Follow up questions:
1. AA says that same day standby is forbidden from PIT-ORD (Two earlier flights that day... easy solution), even for Explats. While I heard that on the phone, I didn't see a restriction in the terms of standby. Any advice?

2: If I miss the connection, do I go to BA for rebooking, or head back to AA? Purchased through AA Explat desk on the phone.

Thanks,
V