The effect of detected and undetected failures of the navigation means (facilities external to the aircraft, including signal-in-space) intended to be used for the operation should be considered. The guidance of this Section is intended to address non-aircraft system errors. Due to the fact that low-visibility procedures (LVPs) are in place for SA CAT I operations, the effects of interruption or disturbance of the ground navigation means by surface movement in sensitive or critical aerodrome areas does not need to be considered.
A description of the possible fault modes of the navigation means (facilities external to the aircraft, including signal-in-space) that are derived from ICAO Annex 10 Volume I can be found in Appendix 1 to AMC to Subpart A. It includes a description of detected failures and the probability of undetected failures. In the demonstration, credit may be taken for the ground subsystem' s probability of undetected failures.
Note: Detected localiser and glide (or equivalent) threshold and time-to-alert and probability of undetected failures depend on the class of the navigation means. Demonstration made for CAT II/III systems may not be applicable for lower-class navigation means.
Failures of the navigation means (facilities external to the aircraft, including signal-in-space) which would require pilot recognition in relation with external references (as required by AMC5 SPA.LVO.105(c) point (d)) should be demonstrated in the actual visual references available on an SA CAT I (or equivalent type sought) runway (see CS AWO.B.SACATI.117).
Navigation means (facilities external to the aircraft, including signal-in-space) should ensure a minimum vertical clearance of 1 m (3 ft) from the obstacle clearance surface, including height loss during the missed approach if applicable in the event of a failure (detected or undetected). If flight crew action is required to trigger a missed approach procedure, a standard delay of 1 s should be considered after flight crew detection. The probability of exceeding the 1 m (3 ft) clearance from the obstacle clearance surface due to navigation means shall be demonstrated to be lower than 10 -7 per approach. In addition, if automatic landing is provided, it should be demonstrated that the probability of landing outside the limits that define a safe landing due to navigation means is lower than 10 -7 .
Easy Access Rules for All-Weather Operations (CS-AWO)
SECTION 2 -AIRWORTHINESS CERTIFICATION OF AEROPLANES FOR OPERATIONS WITH DECISION HEIGHTS (DHs) BELOW 60 M (200 FT) AND DOWN TO 45 M (150 FT) -SPECIAL AUTHORISATION CATEGORY I (SA CAT I) OPERATIONS
The effect of the probability of failure of the navigation means (facilities external to the aircraft, including signal-in-space) should be considered and the effect on the go-around rate should be investigated.
[Issue: CS-AWO/2]