The calculated distance (air line) between Hollogne-aux-Pierres and Uccle is approximately 51 miles respectively 82 kilometers.
By car or train, the actual journey to Uccle is certainly longer, as only the direct route (as the crow flies) between Hollogne-aux-Pierres and Uccle has been calculated here.
Air line (approximately)
82 kilometers
44 nautical miles