Which description identifies the STOP hand signal?

• A. Right arm extended, palm down and open, move arm back and forth horizontally.
• B. Left arm extended, palm down and open, move arm back and forth horizontally.
• C. Right arm extended, palm up and closed.
• D. Right arm extended, palm down and open, held still.

Answer: (A)

Stop signaling uses a specific motion to halt crane movement. The defining gesture is an arm extended straight out, with the palm facing downward and the hand open, and the signaler moves the arm back and forth horizontally. Doing this with the right arm ensures the signal is clearly visible and unambiguous to the operator. This combination—right arm extended, palm down and open, moving side to side—is the clear cue to stop. Using the left arm, or palm up and closed, or simply holding the arm still would not communicate the stop command in the standard signaling language.