CAT II (Category II) precision approach is an advanced instrument landing procedure that provides vertical and lateral guidance for aircraft in low-visibility conditions, with stricter requirements than CAT I. This glossary entry covers definitions, requirements, equipment, training, regulatory framework, and operational procedures for CAT II approaches in aviation.
A CAT II (Category II) precision approach is an advanced instrument landing procedure designed for aircraft operations in low-visibility conditions. Defined by the International Civil Aviation Organization (ICAO), a CAT II approach provides both lateral and vertical guidance to the pilot, supporting safe landings when natural visual cues are insufficient. The hallmark of CAT II is a decision height (DH) lower than 200 feet but not lower than 100 feet above the runway threshold, combined with a runway visual range (RVR) of no less than 300 meters.
CAT II bridges the operational gap between basic CAT I approaches, which have higher minima and less demanding requirements, and the highly sophisticated CAT III procedures, which allow for landings in near-zero visibility. By enabling landings during periods of fog, heavy precipitation, or low cloud ceilings, CAT II approaches are vital for major commercial airports, cargo hubs, and business aviation operators seeking to maintain schedule reliability and minimize weather-related disruptions.
Successful CAT II operations depend on strict compliance with technical, operational, and regulatory standards. Both the aircraft and crew must be specifically certified, the airport must provide high-integrity navigation aids and lighting, and real-time RVR data must be available. This ensures that CAT II approaches are conducted safely, even in adverse meteorological conditions.
Precision approach categories are defined by the minimum DH and RVR permitted. The following table summarizes the key differences:
| Category | Decision Height (DH) | Runway Visual Range (RVR) |
|---|---|---|
| CAT I | ≥ 200 ft (60 m) | ≥ 550 m |
| CAT II | < 200 ft (60 m), ≥ 100 ft (30 m) | ≥ 300 m |
| CAT IIIA | < 100 ft (30 m) or none | ≥ 175 m |
| CAT IIIB | < 50 ft (15 m) or none | 50–175 m |
| CAT IIIC | No DH | No RVR limitation |
CAT II approaches require more advanced technology and pilot training than CAT I, but are less demanding than CAT III, which can allow landings even when no visual reference is available.
ICAO’s Annex 6 (Operation of Aircraft) and Annex 14 (Aerodromes) establish the global requirements for CAT II approaches, including:
These frameworks ensure that only qualified operators, trained crews, and properly equipped aircraft and airports conduct CAT II approaches.
To support CAT II operations, airports must be equipped with:
All systems must be continuously monitored and maintained, with immediate notification and suspension of CAT II operations if any critical system fails or degrades.
Aircraft authorized for CAT II approaches must have:
All equipment is subject to rigorous certification, regular functional checks, and prompt maintenance to ensure operational readiness.
Pilots must gain special CAT II authorization through:
Ongoing recurrent training and proficiency checks are mandatory to retain CAT II privileges.
Operators must submit to their regulatory authority:
Approval is only granted after thorough documentation and practical demonstration of safe CAT II operations, with continued oversight and periodic revalidation.
A CAT II approach involves:
These procedures, combined with equipment redundancy and rigorous crew training, minimize risks such as controlled flight into terrain (CFIT) and runway excursions.
| Feature | CAT I | CAT II | CAT III (A/B/C) |
|---|---|---|---|
| Decision Height (DH) | ≥ 200 ft | 100–200 ft | < 100 ft (A); < 50 ft (B); none (C) |
| Minimum RVR | ≥ 550 m | ≥ 300 m | 175 m (A); 50 m (B); none (C) |
| Radio Altimeter | Not required | Required | Required |
| Autopilot/Flight Director | Not required | Required | Required (higher redundancy) |
| Crew Authorization | Instrument rating | Additional CAT II | CAT III-specific |
| Equipment Redundancy | Standard IFR | Enhanced | Maximum redundancy |
| Typical Use Cases | Most airports | Major airports, low vis | Major airports, very low vis |
A CAT II (Category II) precision approach is a cornerstone of modern aviation, enabling safe, reliable landings in conditions that would otherwise preclude visual approaches. It requires a synergy of advanced airport infrastructure, certified aircraft equipment, and specially trained crews, all governed by stringent international and national regulations. As weather unpredictability and airport congestion increase, CAT II approaches play an ever more vital role in the efficiency and safety of global air transport.
For further reading, see related glossary entries on Instrument Landing System (ILS) , Runway Visual Range (RVR) , and Decision Height (DH) .
If you have additional questions or need support with CAT II implementation, contact our aviation experts or schedule a consultation .
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