Dual-function protein that regulates the transcription of class 2 flagellar operons and that also acts as an export chaperone for the filament-capping protein FliD. As a transcriptional regulator, acts as an anti-FlhDC factor; it directly binds FlhC, thus inhibiting the binding of the FlhC/FlhD complex to class 2 promoters, resulting in decreased expression of class 2 flagellar operons. As a chaperone, effects FliD transition to the membrane by preventing its premature polymerization, and by directing it to the export apparatus