Which initial cockpit indications should a pilot be aware of when a constant headwind shears to a calm wind?

When transitioning from a constant headwind to a calm wind, it is crucial for pilots to understand that the loss of headwind component affects their lift and airspeed. As the headwind decreases to calm, the aircraft experiences a reduction in aerodynamic support due to the diminished relative wind against the wings.

In this scenario, the initial indications in the cockpit would reflect a decrease in altitude, pitch, and indicated airspeed. The aircraft's lift is partially dependent on airspeed, and with the reduction in headwind, the indicated airspeed would decline. As a result, this could lead to a loss of altitude if the pilot does not adjust for the change, typically requiring an increase in pitch to maintain level flight. Therefore, the correct understanding of these dynamics aligns with the observations made in the provided answer.