Base Leg 1 : A flight path at right angles to the landing runway off its approach end and extending from the downwind leg to the intersection of the extended runway centerline
Ilan Kelman (ed.), Vulnerability and Resilience Definitions and References, Version 2, 2007. http://www.islandvulnerability.org/docs/vulnres.pd f, (Vulnr and Resilience - Brit) {524}