A U-turn. Taken from the name of a manuver used by airplanes to accomplish much the same thing; that is, a swift reversal of direction. Example: Wrong way. Just pull an Immelman--no one's looking.
IMMELMAN (TO PULL A)
Meaning of IMMELMAN (TO PULL A) in English
Slang English vocab. Английский сленговый словарь. 2012