FlyerTalk Evangelist
Join Date: Aug 2011
Location: Barcelona, London, on a plane
Programs: BA Silver, TK E+, AA PP, Hyatt Globalist, Marriott LT Plat, Hilton Diamond
Posts: 13,057
AV won't have the obligation to reroute you on a different airline. However airport control has more leeway than phone agents, so you can always arrive early to MAD armed with Plan B options and see if somebody from AV is feeling proactive / generous.
Since the flight departs the EU, however, AV would be required to compensate you under EC261 rules should you miss your connecting flight and arrive late into LAX. It's also entirely possible that the LAX flight will be held for you (or will be delayed).
That said, AV should eventually get around to determining that your itinerary is illegal due to MCT, and you will be entitled to a refund or to accept whatever rerouting they offer you. (no compensation if more than 14 days ahead of departure)
There is nothing you can do about a 787 being downgraded to an A320. Some airlines offer goodwill compensation, others don't. AV probably don't...
P.S. A schedule change isn't IRROPs