Vutthāna-gāminī-vipassanā: 'insight leading to path ascent'. It is also called 'cleansing' vodāna, and according to Pts.M. II, 64, it is a name for 3 kinds of insight-knowledge, namely: knowledge consisting in the desire for deliverance muccitu-kamyatā-ñāna see: visuddhi VI 6; reflecting-contemplation-knowledge patisankhānupassanā-ñāna ib. VI, 7; and knowledge consisting in equanimity regarding all constructions sankhārupekkhā-ñāna see: visuddhi VI, 8.
It arises at the stage of 'purification by knowledge and vision of the path-progress' see: visuddhi VI, and is followed immediately by the change-of-lineage moment and the entrance into the supra-mundane paths.
'Ascent' vutthāna is the supra-mundane path see: ariya-puggala since it rises above the object forming the external foundation of insight; i.e. the external 5 groups of existence, in which object one's mind was absorbed, and also rises above one's own continuity one's own 5 groups of existence, or khandha together with its defilements. By reason of its leading upwards to the supra-mundane path, this insight is called 'ascending insight'. That it passes on to the path: that is the meaning implied; Vis.M XXI, 83f.
Maha Thera Nyanatiloka. Manual of Buddhist Terms and Doctrines, Buddhist Publication Society, first edition 1952.