Before landing gear is extended, how many chimes are given?

Before the landing gear is extended, a single HI/LO chime is produced to alert the crew. This chime serves as an important indication that the aircraft is transitioning to a critical phase of flight where the landing gear must be properly deployed. The HI/LO chime is specifically designed to capture the attention of the flight crew, ensuring they are aware of the upcoming action required concerning the landing gear.

The reason this particular chime is used instead of a steady chime or multiple chimes is to provide a distinct auditory signal that signifies a change in flight operations. It helps to draw attention and confirms that the aircraft is at the correct altitude and configuration for landing procedures. This chime plays a crucial role in maintaining situational awareness during the landing process and facilitating smooth communication among crew members.