Wav from ProTools had me confuse at beginning, incompatible wav in FCP.
Open Terminal and change the attribue of file to make it compatible in FCP
type in terminal:
cd (drag folder to insert path)
xattr -d com.apple.FinderInfo */Volumes/...../...../Path to folder containing wav file.
and those wav will import in FCP, no need to transcode those in aiff.
With that you will keep timecode and metadata of Broadcast wav file
enjoy