For straight-in approaches to SFO/ELP, where should you issue clearance or alternate instructions?

Issuing clearance or alternate instructions on final, no closer than 3 miles from the runway, is ideal because it allows sufficient time for the aircraft to acknowledge and respond to the instructions without disrupting the aircraft's approach and landing sequence. This practice enhances safety by ensuring that the pilot is fully engaged in the landing process while still providing an appropriate window to handle any necessary adjustments or preparations regarding alternate plans.

This distance provides the crew with a clear and manageable timeframe to review the incoming instructions, which is especially important in busy terminal environments like SFO/ELP, where situational awareness is critical. Furthermore, issuing instructions too close to the runway could lead to confusion or potential errors during a critical phase of flight, making the 3-mile distance a safer standard for communication.

The other options would not be appropriate due to the operational context or timing; issuing instructions at the runway threshold would be too late for effective communication, while doing so at the initial approach fix would be too early in the descent sequence for the final approach phase. Similarly, issuing instructions at the low key position may interfere with the aircraft's transition to final and could potentially overload the crew with information at a critical moment.