CS AWO.B.SACATI.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 45 m (150 ft) — Special Authorisation Category I (SA CAT I) operations, using a precision approach system as defined in ICAO Annex 10, which has outputs indicating the magnitude and sense of deviation from a preset azimuth and elevation angle giving equivalent operational characteristics to those of a conventional ILS. (See AMC AWO.B.SACATI.101)

[Issue: CS-AWO/2]

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

ED Decision 2022/007/R

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 navigation receiver(s) and instruments and their installation have been approved. The purpose of this Section is to specify the supplementary airworthiness requirements for the performance of approaches on authorised Category I xLS runways with DHs below 60 m (200 ft) down to 45 m (150 ft). Authorised runway criteria include xLS categories that are suitable for the intended operation and the pre-threshold terrain is compatible with the use of a radio altimeter (or other device capable of providing equivalent performance and integrity level) at a DH of 45 m (150 ft).

Terminology

(a) The term ‘approach system’ refers only to the airborne system. It includes the equipment listed in AMC AWO.B.SACATI.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 this Section, it means the minimum DH at which compliance with the requirements of this Section has been demonstrated.

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

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

(e) The terms ‘localiser’,’glide path’ and ‘beam’ have been retained for use with either ILS or an equivalent system.

(f) ‘ILS or equivalent system’ is understood as ILS, MLS and GLS. It may include other xLS systems if they demonstrate the same global level of precision, integrity and continuity as an ILS CAT II operation with a DH of 150 ft.

(g) ‘HUD or equivalent display’ is understood as HUD or head-worn display (HWD).

Guidance on controls, indicators and alerts that are associated with installations that incorporate more than one type of approach system can be found in AMC AWO.A.ALS.110.

System concept

The principle of SA CAT I operations is to provide a lower DH than the standard CAT I operation by mitigating xLS performance category characteristics that may be not suitable for CAT II operations and reduced runway lighting by additional approach system requirements. These requirements intend to compensate for lower accuracy and integrity and longer time-to-alert than those required for CAT II operations, and provide assistance to acquire the visual cues required to complete the landing with reduced lighting.

Systems that have shown or can demonstate compliance with CS-AWO Subpart B Section 3 (CAT II) are considered to be eligible for SA CAT I operations if it has been demonstrated that they can be safely used in a CAT I environment. Other systems can be considered if suitable justification and mitigation means can be provided.

Due to the fact that low-visibilty procedures (LVPs) are required to be in place for SA CAT I operations, the following non-exhaustive list of approach systems may be considered for SA CAT I operations:

(a) HUD (or equivalent display) with flight guidance which is approved for xLS manual operation down to 36 m (120 ft).

(b) SVGS with flight guidance based on xLS displayed on the primary flight display or HUD (or equivalent display), and high-precision position assurance monitoring.

(c) Automatic approach system coupled down to 36 m (120 ft) with a HUD (or equivalent display) to ease manual transition at the DH, thanks to the control of the flight path vector (FPV) in the visual segment.

(d) Automatic landing system alone, provided it is demonstrated that failures linked to Category I xLS performance can be recognised by pilot in low-visibility conditions.

(e) Automatic landing system with a HUD (or equivalent display) to monitor the autoland path along the Category I xLS performance before and after the DH.

[Issue: CS-AWO/2]

CS AWO.B.SACATI.102 Safety level

ED Decision 2022/007/R

The safety level for precision approaches with DHs below 60 m (200 ft) down to 45 m (150 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.SACATI.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 a DH below 60 m (200 ft).

[Issue: CS-AWO/2]

CS AWO.B.SACATI.103 Go-around rate

ED Decision 2022/007/R

(See AMC AWO.B.SACATI.103)

The proportion of approaches that terminate in a go-around below 150 m (500 ft) due to the approach system performance or reliability shall not be greater than 5 %, taking into account go-arounds that are caused by on-board navigation receivers.

[Issue: CS-AWO/2]

AMC AWO.B.SACATI.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 45 m (150 ft) in no more than 5 % of the approaches.

(b) A glide path excess-deviation alert will occur between 90 m (300 ft) and 45 m (150 ft) in no more than 5 % of the approaches.

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

ED Decision 2022/007/R

The approach system shall:

(a) either 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;

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

[Issue: CS-AWO/2]

CS AWO.B.SACATI.106 Control of speed

ED Decision 2022/007/R

Automatic throttle/thrust 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.SACATI.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 control).

(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.SACATI.107 Manual control

ED Decision 2022/007/R

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

[Issue: CS-AWO/2]

CS AWO.B.SACATI.108 Oscillations and deviations

ED Decision 2022/007/R

The approach system shall not cause 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 operations.

[Issue: CS-AWO/2]

CS AWO.B.SACATI.109 Decision height (DH) recognition

ED Decision 2022/007/R

The recognition of the decision height (DH) shall be made by means of height measured by a radio altimeter or another system that provides height above terrain with equivalent performance, accuracy, integrity, availability, level of independence, and dissimilarity.

[Issue: CS-AWO/2]

CS AWO.B.SACATI.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]