Abstract: Tone correction factor is introduced to account for the influence of noise spectral irregularities on human subjective sensation when calculating the effective perceived noise level (EPNL) in civil airplane noise airworthiness certification. But the flight noise acquired by microphone mounted above ground contains pseudo tones induced by ground interference effect and the pseudo tones usually cause the tone correction factor to be overestimated. In order to identify and remove the influence of pseudo tones on tone correction factor, the flight test and data analysis method are presented. During flight tests an inverted-microphone device placed nearby reference noise measuring point is used to identify the pseudo tones precisely. On the basis of the treatment methods recommend by CCAR-36 and its annex, a new method of removing the influence of pseudo tones is presented. Then the flight test and data analysis method are verified by flyover noise tests of a certain civil airplane. The results show that the methods can identify and remove the influence of pseudo tones more precisely and conveniently and still meet the requirements of airworthiness regulations.