1.1   Categories of Aircraft

Aircraft performance has a direct effect on the airspace and visibility needed to perform the various manoeuvres associated with the conduct of instrument approach procedures. The most significant performance factor is aircraft speed. Accordingly, the following five categories of typical aircraft have been established, based on 1.3 times stall speed V_so or 1.23 times stall speed V_slg in the landing configuration at maximum certificated landing mass (if both V_so and V_slg are available, the higher resulting value is applied), to provide a standardized basis for relating aircraft manoeuvrability to specific instrument approach procedures:

• CAT A: less than 91 KIAS;
• CAT B: 91 KIAS or more, but less than 121 KIAS;
• CAT C: 121 KIAS or more, but less than 141 KIAS;
• CAT D: 141 KIAS or more, but less than 166 KIAS;
• CAT E: 166 KIAS or more, but less than 211 KIAS.

As indicated in § 1.3 below, a specified range of handling speeds for each category of aircraft has been assumed for use in calculating airspace and obstacle clearance requirements for each procedure.

The IAC will specify the individual categories of aircraft for which the procedure is approved. Normally, procedures will be designed to provide protected airspace and obstacle clearance for aircraft up to and including CAT D. However, where airspace requirements are critical, procedures may be restricted to lower speed categories. Alternatively, the procedure may specify a maximum IAS for a particular segment without reference to aircraft category. In any case it is essential that pilots comply with the procedures and information depicted on instrument flight charts and the appropriate flight parameters shown in § 1.3 below if the aircraft is to remain in the areas developed for obstacle clearance purposes.

1.2   Obstacle Clearance

Obstacle clearance is a primary safety consideration in the development of instrument approach procedures. The criteria used and the detailed method of calculation is covered in ICAO Doc 8168, Volume II. However, from the operational point of view it is stressed that the obstacle clearance applied in the development of each instrument approach procedure is considered to be the minimum required for an acceptable level of safety in operations.

1.4   Naming Convention for Waypoints Used in Instrument Approach Procedures

• IAF is pronounceable letter name code (except in Luxembourg);
• IF is a 5 alphanumeric name code finishing with letter “I” or a pronounceable letter name code (if operational advantage);
• FAF is a 5 alphanumeric name code finishing with letter “F”;
• Where MAPT is co-located with THR, WPT is named as “RWxx (RUNWAYdesignator)”. Otherwise the WPT is named as “MAPxx (RUNWAYdesignator)”.

1.5   Arriving Flights

Controlled flights entering and landing within a TMA will be cleared to a specified holding point and instructed to contact APP at a specified time, level or position. The terms of this clearance shall be adhered to until further instructions are received from APP. If the clearance limit is reached before further instructions have been received, holding procedure shall be carried out at the level last authorized.

Due to the limited airspace available, it is important that the approaches to the holding patterns and the holding procedures be carried out as precisely as possible. Pilots are strongly requested to inform ATC if for any reason the approach and/or holding cannot be performed as required.

1.6   Departing Flights

Flights departing from controlled aerodromes will receive initial ATC clearance from the local TWR. The clearance limit will normally be the aerodrome of destination.

Flights departing from non-controlled aerodromes and intending to enter controlled airspace are required to file a flight plan with the nearest ATS unit prior to departure. However, where a non-controlled aerodrome is located outside a CTR and where telephone facilities are not available, flight plans may be filed during flight. In those cases pilots should ensure that the flight plan is filed at least 10 MIN before entering controlled airspace and that RTF transmissions are kept to a minimum.

2.1   Categories of Aircraft

Aircraft performance has a direct effect on the airspace and visibility needed to perform certain manoeuvres, such as circle to land, turning missed approach, final alignment correction to land and descent. The most significant performance factor is aircraft speed. Accordingly, the following five categories of aircraft have been established, based on 1.3 times stall speed in the landing configuration at maximum gross landing weight. The OPS authority determines the category of minima required and to be used by their aircraft.

• CAT A: less than 91 KIAS;
• CAT B: 91 KIAS or more, but less than 121 KIAS;
• CAT C: 121 KIAS or more, but less than 141 KIAS;
• CAT D: 141 KIAS or more, but less than 166 KIAS;
• CAT E: 166 KIAS or more.

2.3   Information About The Use of Instrument Procedures Plates

2.3.3   Landing Minima

See below for the explanation of the landing minima as it is represented in the BEMIL FLIP - IFR (High and Low Instrument Approach and Departure Procedures Belgium).

Landing minima are established for six aircraft categories, determined as follow:

CAT	APPROACH SPEED
A	Less than 91 KT
B	91 KT or more but less than 121
C	121 KT or more but less than 141
D	141 KT or more but less than 166
E	166 KT or more
HPMA	See page IV in BEMIL FLIP - IFR

Note 1: Speeds are based on 1.3 times the stall speed in the landing configuration at maximum gross landing weight.

Note 2: Operational authorities determine the category of minima required and to be used by their aircraft.

Standard portrayal of instrument approach minima for landing is as follows.

• Only “estimated horizontal visual range on ground” is available for Belgian military airfields.
• The VIS value published following the DA or the MDA is the required minimum for the approach.
• Pilots should consult applicable directives of their respective service for aircraft restrictions.