1 Approach
The supporting flight tests to show compliance with CS AWO.B.CATIII.115(a) in respect of approach performance may be a programme of flight demonstrations carried out in accordance with AMC AWO.B.CATII.113.
2 Touchdown
For compliance with CS AWO.B.CATIII.115(b) in respect of touchdown performance, a programme of flight demonstrations will be required to support the simulation and analysis. (See AMC AWO.A.ALS.106) 3 Ground roll
3.1 A programme of landings should be carried out to ensure that there is a confidence level of 90 % that the criterion of CS AWO.B.CATIII.117(a) is complied with. This programme and the analysis of the results should be in accordance with the procedures established for approach performance. (See AMC AWO.B.CATII.113 paragraph 2)
3.2 When operation is based on fail-operational ground roll, a programme of flight demonstration landings is necessary to support the simulation and the analysis programme which are required to demonstrate compliance with CS AWO.B.CATIII.117(b). (See AMC AWO.A.ALS.106) 4 Considerations for GLS
4.1 Compatibility with rare undetected non-aircraft system error conditions (See Appendix 1 to AMC to Subpart A) The criteria below establish the compatibility of the ICAO standardised ground monitoring performance for satellite faults and single ground-reference receiver faults with the aircraft performance including satellite geometry screening. The criteria ensure that undetected faults or rare normal errors in non-aircraft GBASs, when combined with all other nominal factors that affect landing performance, do not result in an unacceptably high probability of landing outside the limits that define a safe landing.
Note: Appendix 1 to AMC AWO.B.CATIII.115 GBAS performance model for approach and landing simulation contains a list of references that have been used to derive the signal model. These references describe undetected non-aircraft system error conditions, rare normal performance and faults as well as the ICAO standardised ground system monitoring requirements. The aircraft requirements in this Section are intended to address non-aircraft system errors that are below the ground monitoring thresholds. The existence of such errors is not considered a malfunction of the non-aircraft system.
For any value of GLS NSE, including the effects of undetected satellite faults and undetected faulted conditions at a single ground-reference receiver, it must be shown that the touchdown performance will be such that the exceedance of any of the limits prescribed in CS AWO.A.ALS.106(c) will be less than those prescribed in AMC AWO.A.ALS.106 paragraph 1.4 for the limit condition.
Other non-GLS variables that effect performance shall vary according to their expected distributions when assessing this compatibility. Credit for the prior probability of the fault cannot be taken when evaluating the required landing probabilities; however, credit may be taken for the ground subsystem’s probability of detection for satellite faults and the aircraft’s probability of detection for single-reference receiver faults.
Note: It is assumed that operations will be approved with knowledge of the runway-specific glide path and threshold crossing height values and the aircraft’s capability. Therefore, it is not necessary to determine compliance with this Section using the glide path and threshold crossing height values set to the limit allowed for the aircraft.
4.2 Compatibility with worst-case undetected guidance errors
Rare ionosphere events and undetected satellite or ground station failures could result in significant vertical (and lateral) position errors. Under certain conditions, such errors may go undetected by the system and could result in erroneous guidance if not mitigated. The effect of such errors may not be observable by the flight crew.
All undetected errors that are not extremely improbable shall not prevent a safe landing and/or go-around when all other variables that effect the performance are at their nominal values. The effect of worst-case undetected errors on landing system performance shall be assessed via simulation using the GLS noise model provided in Appendix 1 to AMC to Subpart A. The worst-case undetected errors shall be simulated by using the maximum range domain error given in Table 5 of Appendix 1 to AMC to Subpart A in conjunction with the appropriate geometry screening factors used by the aircraft. The certification plan must specify how the demonstration will be conducted, including the number of cases and variables with pass–fail criteria. The aeroplane performance shall be assessed in the presence of the full range of bias and ramp type failures produced by the fault mode generator described in Appendix 1 to AMC to Subpart A.
[Issue: CS-AWO/2]