CS AWO.B.CATII.101 Applicability

ED Decision 2022/007/R

This section is applicable to aeroplanes for which certification is sought to allow the performance of approaches with DHs below 60 m (200 ft) down to 30 m (100 ft) — Category II operations, using a precision approach system as defined in ICAO Annex 10 (See AMC AWO.B.CATII.101(a)).

[Issue: CS-AWO/2]

AMC AWO.B.CATII.101(a) Applicability and terminology

ED Decision 2022/007/R

An xLS (as defined in CS AWO.B.CATI.102) which has outputs that indicate the magnitude and sense of deviation from a preset azimuth and elevation angle giving operational characteristics equivalent to those of a conventional ILS is considered a precision approach system.

An aeroplane with a basic airworthiness approval for IFR operations is eligible to perform xLS precision approaches down to a DH of 60 m (200 ft), assuming that the necessary xLS receiver(s) and instruments and their installation have been approved. The purpose of Subpart B Section 3 is to specify the supplementary airworthiness requirements for the performance of xLS approaches with DHs below 60 m (200 ft) down to 30 m (100 ft). Depending upon the applicable operational regulations, aeroplanes that are certified in accordance with this Section may also be eligible to conduct SA CAT II operations.

Terminology

(a) The term ‘approach system’ used here refers only to the airborne system. It includes the equipment listed in CS AWO.B.CATII.111, and all related sensors, instruments and power supplies.

(b) ‘Decision height (DH)’ is the wheel height above the runway elevation by which a go-around must be initiated unless adequate visual reference has been established and the aircraft position and approach path have been visually assessed as satisfactory to continue the approach and landing safely. Where ‘DH’ is used in Section 3, it means the minimum DH for which compliance with the requirements of Section 3 has been demonstrated.

(c) A ‘go-around’ is the transition from an approach to a stabilised climb.

(d) ‘Failure condition’ and the terms describing the probabilities and effects of failure conditions are defined in AMC 25.1309.

The term ‘localiser’ and ‘glide path’ have been retained for use with either ILS, MLS or GLS.

Cross reference is made in this Section to AMC AWO.A.ALS.110 which provides guidance on controls, indicators and alerts associated with installations incorporating more than one type of approach system (e.g. ILS and MLS and/or GLS).

[Issue: CS-AWO/2]

CS AWO.B.CATII.102 Safety level

ED Decision 2022/007/R

The safety level for precision approaches with DHs below 60 m (200 ft) down to 30 m (100 ft) shall not be less than the average safety level achieved in precision approaches with DHs of 60 m (200 ft) and above.

[Issue: CS-AWO/2]

AMC AWO.B.CATII.102 Safety level

ED Decision 2022/007/R

The safety level, achieved by complying with the performance and failure requirements of this Section, should be equivalent to or better than the safety level for operations with DHs of 60 m (200 ft) or above. Hence, in showing compliance with the performance and failure requirements, the probabilities of performance or failure effects should not be factored by the proportion of approaches, which are made with the DH below 60 m (200 ft).

[Issue: CS-AWO/2]

CS AWO.B.CATII.103 Go-around rate

ED Decision 2022/007/R

(See AMC AWO.B.CATII.103)

The proportion of approaches terminating in a go-around below 150 m (500 ft) due to the approach system performance or reliability shall not be greater than 5 %.

[Issue: CS-AWO/2]

AMC AWO.B.CATII.103 Go-around rate

ED Decision 2022/007/R

Based on the assumption that system failures will not significantly reduce the success rate, compliance may be demonstrated by means of the continuous method of AMC AWO.B.CATII.113 using the following interpretation:

(a) A localiser excess-deviation alert will occur between 90 m (300 ft) and 30 m (100 ft) in no more than 5 % of approaches.

(b) A glide path excess-deviation alert will occur between 90 m (300 ft) and 30 m (100 ft) in no more than 5 % of approaches.

[Issue: CS-AWO/2]

CS AWO.B.CATII.104 Flight crew workload

ED Decision 2022/007/R

The workload associated with the use of the approach system shall be considered in showing compliance with CS 25.1523, AMC 25.1523, and CS-25 Appendix D.

[Issue: CS-AWO/2]

CS AWO.B.CATII.105 Control of flight path

ED Decision 2022/007/R

The approach system shall either:

(a) provide information of sufficient quality to the flight crew to permit the manual control of the aeroplane along the flight path within the prescribed limits; or

(b) automatically control the aeroplane along the flight path within the prescribed limits.

[Issue: CS-AWO/2]

CS AWO.B.CATII.106 Control of speed

ED Decision 2022/007/R

Automatic speed control shall be provided unless it is demonstrated in flight that speed can be controlled manually by the flight crew within the acceptable limits and without excessive workload. When making an approach using an automatic throttle/thrust system the approach speed may be selected manually or automatically.

[Issue: CS-AWO/2]

CS AWO.B.CATII.107 Manual control

ED Decision 2022/007/R

(a) In the absence of a failure, the approach down to the DH shall not require a change in the means of control (e.g. a change from automatic to manual).

(b) The use of a manual mode or the transition from an automatic mode to manual control shall not require exceptional piloting skill, alertness or strength.

[Issue: CS-AWO/2]

AMC AWO.B.CATII.107 Manual control

ED Decision 2022/007/R

A change in the means of control is considered a change from automatic control to manual control.

[Issue: CS-AWO/2]

CS AWO.B.CATII.108 Oscillations and deviations

ED Decision 2022/007/R

The approach system shall cause no sustained nuisance oscillations or undue attitude changes or control activity as a result of configuration or power changes or any other disturbance to be expected in normal operation.

[Issue: CS-AWO/2]

CS AWO.B.CATII.109 Decision height recognition

ED Decision 2022/007/R

The recognition of the DH shall be made by means of height measured by a radio altimeter or other device capable of providing for equivalent performance and integrity level.

[Issue: CS-AWO/2]

CS AWO.B.CATII.110 Go-arounds

ED Decision 2022/007/R

Go-arounds shall not require exceptional piloting skill, alertness or strength to maintain the desired flight path.

[Issue: CS-AWO/2]