Which flight instrument systems are required for day VFR flight in controlled airspace?

For day VFR (Visual Flight Rules) flight in controlled airspace, specific flight instruments are essential to ensure safe operation and effective navigation. The requirement for a magnetic direction indicating system is fundamental, as it allows the pilot to understand their heading and navigate effectively within controlled airspace. This is crucial for maintaining the appropriate track and avoiding collisions with other aircraft.

An airspeed indicator is also a required instrument because it provides the pilot with critical information on the speed of the aircraft relative to the surrounding air. This information is vital for performing safe maneuvers and for adhering to the speed limits established for various classes of airspace.

Furthermore, while a vertical speed indicator is not universally mandated for all types of VFR operations, it is commonly included in day VFR flight as it assists the pilot in understanding the rate of climb or descent, which is an important aspect of maintaining safe flight operations, especially in controlled airspace where altitude changes might be more frequent and regulated.

Because all these instruments contribute to a pilot's situational awareness and decision-making abilities in flight, they are collectively required for day VFR flight in controlled airspace, making the answer that includes all of them the correct choice.