FAA Aircraft Dispatcher (ADX)Navigation and ATCMedium
A dispatcher is planning a VFR flight that will operate within 25 NM of a Class B primary airport at 8,000 feet MSL. What equipment must the aircraft have to operate in this area?
- AADS-B Out and an altitude-encoding (Mode C) transponder
- BOnly a Mode C transponder; ADS-B is required only above 10,000 feet MSL
- CTCAS II and RVSM certification
- DA Mode S transponder only, ADS-B is optional below FL180
Show answer & explanationAnswer & explanation
Correct answer: A. ADS-B Out and an altitude-encoding (Mode C) transponder
Per 14 CFR 91.225 and 91.215, aircraft operating within 30 NM of a Class B primary airport, from the surface up to 10,000 feet MSL (the 'Mode C veil'/ADS-B veil), must be equipped with both an altitude-encoding transponder and ADS-B Out. Since 25 NM and 8,000 ft fall within this veil, both are required.
Why the other options are wrong
- B. ADS-B is required within the veil, not just above 10,000 ft.
- C. TCAS II and RVSM apply to high-altitude/large turbine operations, not this scenario.
- D. ADS-B is not optional within the Mode C veil; it's mandatory below 10,000 ft MSL.
Mode C / ADS-B Veil
The airspace within 30 NM of a Class B primary airport, surface to 10,000 ft MSL, requiring both Mode C transponder and ADS-B Out equipment per 91.215/91.225.
- 30 NM radius from Class B primary airport
- Surface to 10,000 ft MSL
- Both altitude-encoding transponder and ADS-B Out required
Memory trick: '30 miles, 10,000 feet — bring your beacon and your broadcast.'