Federal agents who detained a college student after an airport screener found him carrying Arabic-English flashcards with such words as “bomb” and “terrorist” cannot be sued for their actions, a U.S. appeals court said Tuesday. Reversing a lower court ruling, the 3rd U.S. Circuit Court of Appeals in Philadelphia said three Transportation Security Administration agents and two FBI agents were entitled to qualified immunity over Nicholas George’s five-hour detention at Philadelphia International Airport on Aug. 29, 2009.