When planes crash, the pressure is on investigators to uncover what happened. That pressure increases dramatically when the case involves high-profile victims or when examiners disagree about the cause of the accident. Witness three controversial air disasters: a 1958 failed takeoff that wiped out the Manchester United soccer team; the 1985 tragedy of Arrow Air Flight 1285, which killed 248 U.S. soldiers heading home for the holidays; and the 2010 crash that claimed the life of Lech Kaczynski, the president of Poland.