NY -- Standard&Poor's CreditWire 4/17/96 -- Standard&Poor's today has affirmed its ratings of AMR Corp. and unit American Airlines Inc. (see table below), following AMR's announcement that it will establish its SABRE computerized reservation system and related operations as a separate subsidiary (The SABRE Group). About $11.7 billion of securities is affected. The rating outlook remains Stable. AMR's action, which removes SABRE assets from American Airlines, increases the risk that these profitable operations may eventually be "spun off" to shareholders. This risk is mitigated somewhat by the expected transfer of some debt to the new subsidiary and by AMR's improving earnings, cash flow, and balance sheet. American Airlines will sign new 10-year market- rate contracts with