Lowest selectable speed (Vls) is indicated by the:

The lowest selectable speed (Vls) is indicated by the top of the amber strip along the speed scale. This speed is crucial for ensuring safe operation, as it represents the minimum speed that can be selected by the pilot during various phases of flight, particularly during approach and landing.

In the context of speed indications, the amber coloration serves as a cautionary signal, alerting pilots that flying at or below this speed could potentially lead to stalling or other adverse performance situations. Thus, the formation and placement of the amber strip at the indicated point on the scale are critical for the pilot’s awareness and aircraft control.

In contrast, the other references mentioned do not represent Vls. The top of the black and amber strip indicates a different range of speed, the top of the red strip signifies Vmax or the maximum permitted speed, and the tip of the speed trend arrow provides an indication of the speed trend but is not a direct reference to the selectable speeds. Understanding these visual cues on the speed scale is essential for effective aircraft operation and management of airspeed.