Extractor fan

Extractor fans were a function of the Doctor's TARDIS that the Eleventh Doctor was surprised to find existed. They could be turned on with the phrase, "Extractor fans on". The Doctor used them after Melody Pond shot the TARDIS' time rotor and poisonous smoke was emitted, (TV: Let's Kill Hitler) and again after an attempt to navigate to 1938 New York damaged the TARDIS. (TV: The Angels Take Manhattan)