Originally Posted by
nhila
Thank you to the last four posters for clear guidance ... I will advise my wife to simply take the "Fast Pass/ Fast Track" paper they give on AA, go through that Lane, and to stay "airside and connect on the bus to T5 from T3, she would just need to do a basic security check at T5. She can then go to the BA lounge and shower there."
The fast track pass that AA will give her is worthless if she stays airside (although I agree that's what she ought to do). After taking the flight transfers bus from T3 to T5, she can use the fast track lane (on the far right) at T5 security if she is flying J on her connection to MAD. Access to that lane is determined solely by class of travel as shown on the boarding pass, not by having a separate paper pass.
After clearing security, advise your wife to turn left, walk to and descend the escalator, and at the bottom of the escalator make a u-turn and double back to the escalators that will take her back up to the BA south lounge.