What report should be made to ATC without a specific request when not in radar contact?

The correct answer is that a report should be made to ATC when leaving the Final Approach Fix (FAF) inbound on final approach. This is an important communication because it informs air traffic control of your aircraft's position relative to the runway and assists them in managing traffic, particularly in busy airspace. Reporting this position allows ATC to provide appropriate separation from other aircraft and can facilitate smooth arrivals and clearances.

The Final Approach Fix is a key point on the approach procedure, and by reporting when you leave this point, you’re essentially letting ATC know that you're actively engaged in landing, and they can prepare for your arrival at the runway. This notification is standard procedure in instrument flight rules (IFR) operations, especially when you are not in radar contact, ensuring that everyone is aware of your location and intentions.

Other reporting points, such as entering the traffic pattern or controlled airspace, while still important, do not carry the same criticality in terms of proximity to a runway as reporting leaving the FAF. Similarly, reporting at the beginning of a climb after takeoff is less about your flight's immediate interaction with ATC traffic, as the traffic pattern and departure phase typically have established communications and do not necessarily require the same level of detailed