Detailed Topo for retaining wall study. MEGA took flight at one of the State’s four international border crossings to perform a topographical survey. While working in such a high-profile, highly secured area, proper preflight planning was imperative. To ensure that the project was properly coordinated, MEGA worked with a number of agencies, including: The International Bridge Administration, Department of Homeland Security, the General Service Administration (GSA) and Sanderson Field (ANJ) City Municipal Airport. All aerial work went as planned without incident.