GM7 SPA.LVO.110 Aerodrome-related requirements, including instrument flight procedures

SUITABLE AERODROMES — DESKTOP ASSESSMENT — AERODROME DATA SOURCES

As detailed in point (b)(2) of AMC1 SPA.LVO.110, the assessment of the suitability of an aerodrome, including instrument flight procedures, for the intended operations, may be made by a desktop assessment, that should consider aerodrome data.

This GM describes some aerodrome data sources that ICAO Member States provide in accordance with ICAO Annex 4.

(a)     Type A and Type B aerodrome obstacle charts

Aerodrome obstacle charts come in two forms. Type A and B charts may be combined, and the chart is called aerodrome obstacle chart (ICAO Comprehensive). Where a terrain and obstacle chart is provided in electronic form, there is no need to provide Type A or B aerodrome obstacle charts.

(b)     Type A aerodrome obstacle chart (ICAO Annex 4, Chapter 3)

Type A aerodrome obstacle charts are found at most aerodromes approved for LVOs. The function of the Type A chart is to enable an operator to comply with the performance operating limitations in Annex 6. The Type A chart does not have to be provided if there are no take-off obstacles, but a note informing about this is needed according to ICAO Annex 4. The elevation is given to the nearest half-metre or nearest foot. Linear dimensions are shown to the nearest half metre.

(c)      Type B aerodrome obstacle chart (ICAO Annex 4, Chapter 4)

Type B aerodrome obstacle charts contain information about the elevation (at the centre line) of both runways plus the elevation at each significant change of the slope of the runway. The function of the Type B chart is:

(1)     the determination of minimum safe altitudes/heights including those for circling procedures;

(2)     the determination of procedures for use in the event of an emergency during take-off or landing;

(3)     the application of obstacle clearing and marking criteria; and

(4)     the provision of source material for aeronautical charts.

Elevations and linear dimensions are shown to the nearest half metre.

(d)     Aerodrome terrain and obstacle Chart – ICAO (Electronic) (ICAO Annex 4, Chapter 5)

The function of this chart is to:

(1)     enable an operator to comply with the operating limitations of Annex 6, Part I, Chapter 5, and Part III, Section II, Chapter 3, by developing contingency procedures for use in the event of an emergency during a missed approach or take-off, and by performing aircraft operating limitations analysis; and

(2)     support the following air navigation applications:

(i)      instrument procedure design (including circling procedure);

(ii)     aerodrome obstacle restriction and removal; and

(iii)     provision of source data for the production of other aeronautical charts.

Note that this chart may also contain the information required for the PATC.

According to ICAO Annex 4, from November 2015, this chart is made available for aerodromes regularly used by international aviation. The chart is made available in printed form on request.

(e)     Aerodrome chart (ICAO Annex 4, Chapter 13)

According to ICAO Annex 4, an aerodrome chart is provided for aerodromes regularly used by international aviation. The function of this chart is to provide information to facilitate the ground movement of aircraft and in general also to provide essential operational information.

This chart contains information about the height of the threshold and, for PA runways, the highest point of the TDZ. This information may also be included in the text part of the AIP, Chapter AD2 (normally paragraph 2.12 – Runway Physical Characteristics). The elevation is provided to the nearest half metre.

(f)      Precision approach terrain chart (PATC) (Annex 4, Chapter 6)

According to ICAO Annex 4, a PATC is made available for all PA runways Categories II and III at aerodromes used by international civil aviation, except where the requisite information is provided in the aerodrome terrain and obstacle chart — ICAO (Electronic). The chart includes:

(1)     a plan showing contours at 1 m (3 ft) intervals in the area of 60 m on either side of the extended centre line of the runway, to the same distance as the profile, the contours to be related to the runway threshold;

(2)     an indication where the terrain or any object thereon, within the plan defined in (1), differs by ± 3 m in height from the centre line profile and is likely to affect a radio altimeter;

(3)     a profile of the terrain to a distance of 900 m from the threshold along the extended centre line of the runway. Where the terrain at a distance greater than 900 m from the runway threshold is mountainous or otherwise significant to users of the chart, the profile of the terrain should be shown to a distance not exceeding 2 000 m from the runway threshold.

(g)     Summary

(1)     For the determination of runway slopes, the aerodrome obstacle chart, preferably the combined version, appears to provide the best information. The PATC appears to be the best source to determine the elevations and slopes in the approach area.

(2)     If the information provided by different parts of the AIP is inconsistent, this may indicate an error in the data and should be reported to the State of aerodrome or AIP issuing authority, unless the inconsistency is insignificant. It should however be noted that there may be different requirements for accuracy and resolution between different AIP charts or sections, which might cause values to differ slightly.

(3)     It may be difficult to conclusively state which chart is best for determining the runway slope in each case, but the primary source of information is the AIP, and therein the aerodrome obstacle chart and the PATC. As the aerodrome terrain and obstacle chart – ICAO (Electronic) becomes more available, it will probably take over as the primary source of information about both runways and pre-threshold terrain.