If the glide slope and localizer are centered but the airspeed is too fast, what should be adjusted initially?

When the glide slope and localizer beams are centered but the airspeed is too fast, the initial adjustment should focus on power. Reducing power allows for a more gradual descent rate while maintaining control of the aircraft's speed. This adjustment is crucial because it enables the pilot to reach the appropriate approach speed, ensuring a safe and stable descent without overexerting the aircraft's ability to maintain the desired glide path.

Attitude and configuration adjustments are also important, but they are typically secondary when it comes to addressing speed. For instance, altering the aircraft's attitude or configuration can affect drag and lift, but modifying power settings directly impacts the thrust available and descent rate more efficiently in this scenario. Adjusting heading would be irrelevant since both the localizer and glide slope indicate proper alignment with the runway. Thus, focusing on power as the initial adjustment prioritizes maintaining control and safety while preparing for a successful landing.