For safe vertical separation, within how many seconds of when the RA is first displayed is the Pilot Flying (PF) expected to initiate the RA maneuver?

The correct choice is based on established guidelines for handling Resolution Advisories (RAs) during operations in controlled airspace. When an RA is first displayed, the Pilot Flying (PF) is expected to initiate the required maneuver within 5 seconds to ensure safe vertical separation from other aircraft. This time frame is critical because RAs are designed to provide immediate guidance to avoid collisions, and a prompt response helps maintain safety and adherence to the intended flight path.

The urgency of responding within this period is underscored by the dynamics of air traffic and the potential for rapidly changing situations. Delays beyond 5 seconds could lead to situations where the aircraft might not have adequate separation, particularly in busy airspace or when there are rapid changes in altitude. Thus, the 5-second guideline is a crucial parameter that aid in ensuring timely and effective actions are taken to maintain flight safety.