MSA
as defined in Commission Implementing Regulation (EU) 2017/373 of 1 March 2017 laying down…
the lowest altitude which may be used which will provide a minimum clearance of 300 m (1 000 ft) above all objects located in an area contained within a sector of a circle of 46 km (25 NM) radius centred on a significant point, the aerodrome reference point (ARP) or the heliport reference point (HRP)