GDS - Global Distribution System aka Sabre/Amadeus/Galileo
The general public cant access it. You can however check these changes on GF's website though. Click on the flight number and then a new window should pop up giving you the aircraft type used for the flight.
By the way concerning returning to USA...just a fyi Turkish Airlines will be launching new daily nonstop flights to Washington DC and Los Angeles effective Dec 1st 2010. Both routes will be flown daily using an A 332 to IAD and a B 77W to LAX operated nonstop from IST with UA code share!
