...NEW YORK (S&P Global Ratings) Sept. 5, 2018--American Airlines Inc. proposes to increase its term loan B due in October 2021, which is secured by takeoff and landing slots at London's Heathrow International Airport, by $300 million (to a total of $1.0275 billion). The same collateral secures a $1 billion revolving credit facility. The proposed upsize does not affect our '##+' issue-level rating or '1' recovery rating, indicating our expectation of very high (90%-100%; rounded estimate: 95%) recovery of the term loan and revolving credit. The secured term loan increase also does not affect our '##-' issue-level rating and '4' recovery rating, indicating our expectation of average (30%-50%; rounded estimate: 40%) recovery of parent American Airlines Group Inc.'s senior unsecured debt, although we revised the rounded estimate recovery to 40% from 45%). ISSUE RATINGS--RECOVERY ANALYSIS Simulated default assumptions + Simulated year of default: 2022...