MCLOS

MCLOS, an acronym for Manual Command to Line of Sight, is a guidance mode used in early wire-guided missiles, notably anti-tank weapons. In MCLOS, the operator observes the target through a sight and uses a control device, such as a joystick, to send steering commands to the missile. The guidance system transmits these commands to the missile (via a tethered wire) to deflect its flight path so that the missile remains on a line of sight to the target. As the target or missile moves, the operator must continuously adjust the controls to keep the line of sight aligned with the missile's course. The system requires substantial operator skill and sustained attention, and accuracy depends on range, target maneuverability, and wind and terrain.

Because it requires continuous manual input, MCLOS is more demanding and less forgiving than later guidance modes and tends to be less accurate at longer ranges, especially against fast or evasive targets. It also exposes the operator to countermeasures and risk to the launcher.

MCLOS was widely used in early wire-guided anti-tank missiles during the 1960s through the 1980s, before being largely supplanted by semi-automatic modes such as SACLOS, which use onboard seekers to track the target while the operator maintains sighting. MCLOS remains of historical interest for understanding the evolution of guided missiles.