This speed refers to the maximum at which the landing gear on a retractable gear aircraft should be extended or retracted.

The term that refers to the maximum speed at which the landing gear on a retractable gear aircraft should be extended or retracted is known as VLO (Velocity Landing Gear Operating). This speed is crucial because extending or retracting the landing gear beyond this limit can lead to structural damage or malfunction of the landing gear system due to increased aerodynamic forces acting on the aircraft.

VLO is a safety parameter established by aircraft manufacturers during the design phase, and adhering to this speed ensures the overall integrity and safe operation of the aircraft system. It allows pilots to operate landing gear safely without compromising performance or safety.

In contrast, the other terms pertain to different aspects of landing gear or aircraft operations. For instance, VLE, which refers to the maximum speed with the landing gear extended, is important but focuses specifically on operations after the gear is already down. VGO typically refers to the minimum speed for a go-around, and VGE relates to gear extended speed; neither directly addresses the procedure for gear operation speeds. Thus, VLO is the most accurate term for describing the maximum operational speed for extending or retracting the landing gear in retractable gear aircraft.