If you wish to contribute or participate in the discussions about articles you are invited to join SKYbrary as a registered user

Precision Approach

From SKYbrary Wiki

Revision as of 20:53, 11 March 2010 by Timo.Kouwenhoven (Talk | contribs)
(diff) ← Older revision | Latest revision (diff) | Newer revision → (diff)
Jump to: navigation, search
Article Information
Category: General General
Content source: SKYbrary About SKYbrary
Content control: EUROCONTROL EUROCONTROL

A precision approach is an instrument approach and landing using precision lateral and vertical guidance with minima as determined by the category of operation.[1]

Note. Lateral and vertical guidance refers to the guidance provided either by:

a) a ground-based navigation aid; or

b) computer generated navigation data displayed to the pilot of an aircraft.

c) a controller interpreting the display on a radar screen (Precision Approach Radar (PAR)).

Categories of precision approach and landing (including ILS and Autoland) operations are defined according to the applicable DA/H and RVR or visibility as shown in the following table.

Category of Operation Decision Height (DH) (2) RVR Visibility not less than
CAT I not lower than 60 m (200 ft) not less than 550 m 800m
CAT II lower than 60 m (200 ft), but not lower than 30 m (100 ft) not less than 350 m (1)
CAT IIIA lower than 30 m (100 ft) or no DH not less than 200 m
CAT IIIB lower than 15 m (50 ft) or no DH less than 200 m but not less than 50 m
CAT IIIC no DH no RVR limitation

Notes:

(1) Appendix 1 to JAR-OPS 1.430, Table 6, permits the use of an RVR of 300m for Category D aircraft conducting an autoland.

(2) Vertical minima:

  • CAT I Because the aircraft is unlikely to be flying over level ground at the same elevation as the touch-down zone when passing the Missed Approach Point, the vertical minima used in a CAT I approach is measured by reference to a barometric altimeter. In practice, this means that when flying a CAT I approach either a DA or DH may be used.
  • CAT II/III Because greater precision is required when flying a CAT II or CAT III approach, special attention is given to the terrain in the runway undershoot to enable a radio altimeter to be used. CAT II and CAT III approaches are therefore always flown to a DH with reference to a radio altimeter.

CAT II and CAT III instrument approach and landing operations are not permitted unless RVR information is provided.

On reaching the DH, the pilot may continue the approach to land provided that the required visual references have been established. Otherwise the pilot must commence a missed approach procedure.

References

  1. ^ ICAO Annex 6

Further Reading

  • JAR-OPS 1 Subpart E (All Weather Operations).
Personal tools