Which additional equipment is required for IFR operation in Class B airspace, in addition to a VOR receiver and two-way communications capability?

To operate under Instrument Flight Rules (IFR) in Class B airspace, an aircraft must be equipped with specific navigational and communication equipment. In addition to a VOR receiver and two-way communications capability, an operable coded transponder having Mode C capability is essential.

Mode C transponders provide altitude information to air traffic control (ATC), which is crucial for maintaining safe vertical separation among aircraft operating in congested airspace like Class B. This requirement enhances situational awareness not only for the pilots but also for controllers managing high-density traffic.

While some options mention additional equipment such as DME (Distance Measuring Equipment) or GPS, the fundamental requirement for IFR operations specifically cites the need for a Mode C transponder. Therefore, while DME and GPS may enhance navigational capabilities, they are not mandatory for IFR clearance in Class B airspace. The key requirement remains the functioning Mode C transponder, which directly aligns with regulatory standards for safety and traffic management in such critical airspace.