IFR precision approach and minima[PDF]
- take-off, expressed in terms of runway visual range and/or visibility and, if necessary, cloud conditions
- landing in 2D instrument approach operations, expressed in terms of visibility and/or runway visual range, minimum descent altitude/height (MDA/H) and, if necessary, cloud conditions
- landing in 3D instrument approach operations, expressed in terms of visibility and/or runway visual range and decision altitude/height (DA/H) as appropriate to the type and/or category of the operation.
MDA = A specified altitude or height in a 2D instrument approach operation or circling approach operation below which descent must not be made without the required visual reference.
- a two-dimensional (2D) instrument approach operation, using lateral navigation guidance only;
- a three-dimensional (3D) instrument approach operation, using both lateral and vertical navigation guidance.
- Type A: a minimum descent height or decision height at or above 75 m (250 ft); and
- Type B: a decision height below 75 m (250 ft).
- Category I (CAT I): a decision height not lower than 60 m (200 ft) and with either a visibility not less than 800 m or a runway visual range not less than 550 m
- Category II (CAT II): a decision height lower than 60 m (200 ft) but not lower than 30 m (100 ft) and a runway visual range not less than 300 m
- Category IIIA (CAT IIIA): a decision height lower than 30 m (100 ft) or no decision height and a runway visual range not less than 175 m
- Category IIIB (CAT IIIB): a decision height lower than 15 m (50 ft) or no decision height and a runway visual range less than 175 m but not less than 50 m
- Category IIIC (CAT IIIC): no decision height and no runway visual range limitations.
- A ground-based radio navigation aid (NDB, LLZ, VOR, ILS)
- Computer-generated navigation data from ground-based, space-based, self-contained navigation aids or a combination of these.
- Instrument landing system – ILS
- RNAV with vertical guidance
The operating minima for 2D instrument approach operations using instrument approach procedures shall be determined by establishing a minimum descent altitude (MDA) or minimum descent height (MDH), minimum visibility and, if necessary, cloud conditions. The operating minima for 3D instrument approach operations using instrument approach procedures shall be determined by establishing a decision altitude (DA) or decision height (DH) and the minimum visibility or RVR.
Decision making to continue
If, after passing the outer marker or equivalent position in accordance with the sentence above, the reported RVR/visibility falls below the applicable minimum, the approach may be continued to DA/H or MDA/H.
Category of operation
Categories of precision approach and landing 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)||Runway Visual Range (RVR)|
|CAT I||DH ≥ 200 ft (60m)||RVR ≥ 550 m or VIS ≥ 800m
RVR ≥ 1750 ft or VIS ≥ 2400 ft
|CAT II||100 ft ≤ DH < 200 ft||RVR ≥ 300 m|
|CAT IIIA||No DH or DH < 100 ft||RVR ≥ 175 m|
|CAT IIIB||No DH or DH < 50ft||50 m ≤ RVR < 175 m|
|CAT IIIC||No DH||No RVR limitation|
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.
Decision height and Decision altitude
- The instrument phase ends at the published MDA/H or DA/H unless a missed approach is initiated.
- The continued approach to landing from MDA/H or DA/H will be conducted using visual references.
Decision altitude (DA) is referenced to mean sea level and decision height (DH) is referenced to the threshold elevation.
The required visual reference means that section of the visual aids or of the approach area which should have been in view for sufficient time for the pilot to have made an assessment of the aircraft position and rate of change of position, in relation to the desired flight path.
- IFR arrival and approach procedure, Category of aircraft for approach procedures, IFR non precision approach and minima
- ICAO documentation Annex 6 - Operation of Aircraft - Part I - International Commercial Air Transport - Aeroplanes - 10th Edition July 2016 - Chapter 4.2.8
- VID 150259 - Creation
- VID 531824 - Wiki Integration
DATE OF SUBMISSION
- 21:16, 13 November 2019
- This documentation is copyrighted as part of the intellectual property of the International Virtual Aviation Organisation.
- The content of this documentation is intended for aviation simulation only and must not be used for real aviation operations.