FAA Private Pilot Helicopter (PRH)Navigation and AirspaceMedium
A helicopter pilot plans to fly VFR beneath the outer shelf of a Class B airspace area at 2,800 feet MSL, remaining 25 nautical miles from the primary airport. What transponder equipment is required for this flight?
- AA Mode C transponder with automatic altitude reporting is required because the flight is within 30 NM of the primary airport
- BOnly a Mode A transponder without altitude reporting is required at this distance
- CNone, since the aircraft is outside the Mode C veil and below the Class B shelf
- DADS-B In equipment only, since transponders are not required for helicopters
Show answer & explanationAnswer & explanation
Correct answer: A. A Mode C transponder with automatic altitude reporting is required because the flight is within 30 NM of the primary airport
14 CFR 91.215 and 91.225 require aircraft to have an operating Mode C transponder with altitude reporting (and ADS-B Out) within 30 nautical miles of a Class B primary airport, from the surface up to 10,000 feet MSL, regardless of whether the aircraft is inside the Class B airspace boundaries. This area is known as the Mode C veil.
Why the other options are wrong
- B. Mode C, not just Mode A, is required within the veil.
- C. The Mode C veil applies within 30 NM regardless of altitude or lateral Class B boundaries.
- D. Both a Mode C transponder and ADS-B Out are required, not ADS-B alone.
Mode C Veil
An imaginary 30 NM radius circle around a Class B primary airport, from the surface up to 10,000 feet MSL, within which a Mode C transponder and ADS-B Out are required.
- Defined by 14 CFR 91.215 and 91.225
- Applies even outside the actual Class B lateral boundaries
- Extends from surface to 10,000 feet MSL
Memory trick: Veil = a 30-mile 'veil' no one can hide under without Mode C.