Definition
A shipboard precision approach and landing system used by the U.S. Navy that automatically guides an aircraft to a landing on an aircraft carrier. The system tracks the aircraft with a shipboard radar, computes the correct glidepath and lineup to the moving deck, and transmits steering commands to the aircraft's flight control system, allowing a hands-off approach and touchdown in low visibility or at night.
Plain English
A system on a Navy aircraft carrier that flies the airplane down to the deck for the pilot. Radar on the ship tracks the aircraft and sends signals that steer it to a safe landing, even when the pilot can't see the ship clearly.
Context Anchor
Seen in military and naval aviation, especially during carrier approaches, night recoveries, and poor-weather carrier landing procedures.
Derivation
The name describes itself in plain terms: 'automatic' (the system flies the approach without manual pilot control), 'carrier' (an aircraft carrier ship), 'landing system' (equipment that guides the aircraft to touchdown). It is the carrier-based military counterpart to land-based instrument landing systems.
Why Pilots Care
It allows safe carrier landings at night or in low visibility when manual flying would be extremely difficult.
Analogy
Think of it like a highly precise guide helping an aircraft aim for a small moving runway, rather than a normal airport runway fixed on the ground.
Intuition Check
Do not assume “automatic” always means the pilot does nothing. ACLS can provide guidance to the pilot, or it may be coupled to aircraft systems for a more automatic landing, depending on the aircraft, equipment, and procedure being used.
Example Sentence 1
In poor weather at night, the pilot coupled the aircraft to the ACLS for a hands-off approach to the carrier.
Example Sentence 2
During the approach the ACLS computer adjusted the aircraft's flight path to compensate for the carrier's movement through the water.