The purpose of this tender is to establish a six-year framework agreement with operators who support Fluxys in the detection, inspection, and reporting of potential threats to the gas transmission pipeline network in Belgium (approximate annual flying distance: 200,000 km). The scope includes the aerial surveillance of, among others (non-exhaustive): • ongoing or recently completed third-party works (both announced and unannounced); • agricultural activities exceeding a depth of 50 cm, such as drainage installation, deep ploughing, drilling, and specific soil cultivation techniques; • changes in ground surface (e.g. erosion) that may affect pipeline coverage; • missing, damaged, or non-visible Fluxys markers. The tender is divided into four lots, each to be awarded to one operator. Overall, contracts will be concluded with a minimum of two and a maximum of three operators.