Mode C veil
Mode C veil refers to a kind of airspace which surrounds most primary Class B airports within United States. This airspace extends horizontally to a circle of 30 NM radius centered on the airport, and extends vertically from the surface up to 10,000 feet MSL. The name refers to the mode of transponder operation which is required within this airspace (i.e., with very limited exceptions, all aircraft operating within this airspace must have an altitude reporting Mode C transponder in operation). All 37 existing (as of late 2014) Class B airports in the United States, have Mode C veil centered on them.
- 14 C.F.R. 91.215(b)(2)
- FAA's order JO 7400.9Y "Airspace Designations and Reporting Points", effective 2014-09-15, accessed 2014-10-29
- CFR Title 14 Appendix D to Part 91, Section 1