If I'm reading this thread right http://www.flyertalk.com/forum/air-c...-upgrades.html, it should book into T. T earned 100% on UA according to the chart: http://www.united.com/page/article/0,,1180,00.html.

(Disclaimer: I've never used a flight pass and am just repeating stuff I read on FT. It's on the Internet; it must be true. )