Originally Posted by
anabolism
Both flights should use T4. That gives you a decent chance of making it, but given LAX's tendency to have delays on arrival due to gate congestion, I wouldn't be comfortable with it. As well, your scheduled arrival would be right before boarding starts on your connection.
How can you be sure that both flights will use T4? JFK flights almost always use T4, but I can very well see PHX-LAX arriving in T5. In fact, the 8:37 flight yesterday (3/26) arrived in T5 and is scheduled to arrive in T5 today (3/27).
Originally Posted by
anabolism
Unfortunately, the agent you spoke with is misinformed on multiple points. Any connection that is less than the MCT is not permitted to be ticketed and is immediate grounds for rebooking, even if the desired new flight does not have the original inventory. There is no such thing as "less than MCT but fine." However, your flight is within MCT, so the agent was wrong there again. However, because there was a non-trivial schedule change on your ticketed itinerary, you are entitled to be rebooked on a different flight without charge.
Was this "non-trivial"? I'm not sure. Although a 37-minute connection (especially between T5 and T4) may not be within the "sensible connection time," it is a legal connection, as you point out. And according to OP, the originally scheduled time would have given OP an 80-minute connection. So the schedule change was one of only 43 minutes. I'm not sure AA would consider this a "non-trivial" schedule change, even though there are reasonable grounds to say that it is.
If I were OP, I would call back and hope to get a more sympathetic agent.