Originally Posted by dnw
Return:
Arrivals - Yes (if its an overnight flight)
Departures - As this is an AA flight from T3 it is nothing to do with BA (no BA lounges in that terminal)
However, as you're OW Sapphire, it'll be worth your while traipsing over to the CX lounge in T3 to see if it's open at the time at which you're passing through T3. If it is, you have OW access privileges there, and it's much nicer than the crAAp AC. But CX opening times are dependent on the times of their own flights, most of which are in the evening.