Cytoplasmic protein involved in the delivery of the dynein machinery to the motile cilium. It is required for the assembly of the axonemal dynein inner and outer arms, two structures attached to the peripheral outer doublet A microtubule of the axoneme, that play a crucial role in cilium motility. Observed only in the cytoplasm of ciliated cells and absent from cilia. Expressed in testis. Expressed in chordonotal neurons during their differentiation, after neuronal specification but before cilium formation. Also expressed in the non-ciliated mesoderm of stage 12 embryos. Homozygous deletion-mutant flies are not viable. The larvae are smaller but do not display obvious morphological phenotype. RNAi-mediated knockdown in sensory neurons affects flies movement coordination and impairs hearing. Testis-specific RNAi-mediated knockdown does not alter spermatogenesis and in particular the formation of sperm axonemes but it impairs sperm motility. Belongs to the DNAAF5 family.