Appendix D D-1 APPENDIX D. REVIEW OF ICAO DOCUMENT 9574 D.1 ICAO Document 9574.
D.1.1 International Civil Aviation Organization (ICAO) Doc. 9574, Manual on the Implementation of a 300 m (1,000 ft) Vertical Separation Minimum Between FL 290-FL 410 Inclusive, covers the overall analysis of factors for achieving an acceptable level of safety in a given airspace system. The major factors are passing frequency, lateral navigation accuracy, and vertical overlap probability. Vertical overlap probability is a consequence of errors in adhering accurately to assigned flight level (FL), and this is the only factor addressed in the present document.
D.1.2 In ICAO Doc. 9574, Section 2.3.1 restated the vertical overlap probability requirement as the aggregate of height-keeping errors of individual aircraft, which must lie within the TVE distribution expressed as the simultaneous satisfaction of the following four requirements:
D.1.2.1 The proportion of height-keeping errors beyond 300 ft (90 m) in magnitude must be less than 2.0x10-3;
D.1.2.2 The proportion of height-keeping errors beyond 500 ft (150 m) in magnitude must be less than 3.5x10-6;
D.1.2.3 The proportion of height-keeping errors beyond 650 ft (200 m) in magnitude must be less than 1.6x10-7; and D.1.2.4 The proportion of height-keeping errors between 950 ft (290 m) and 1,050 ft (320 m) in magnitude must be less than 1.7x10-8.
D.1.3 The following characteristics presented in ICAO Doc. 9574 were developed to satisfy the distributional limits in paragraph D.1.2.1, and to result in aircraft airworthiness having negligible effect on meeting the requirements in paragraphs D.1.2.2, D.1.2.3, and D.1.2.4.
They are applicable statistically to individual groups of nominally identical aircraft operating in the airspace. These characteristics describe the performance the groups need to be capable of achieving in service, exclusive of human factors errors and extreme environmental influences, if the airspace system Total Vertical Error (TVE) requirements are to be satisfied. The following characteristics are the basis for development of this document:
D.1.3.1 The mean altimetry system error (ASE) of the group must not exceed ±80 ft (±25 m);
D.1.3.2 The sum of the absolute value of the ASEmean for the group and ASE3 SD within the group must not exceed 245 ft (75 m); and D.1.3.3 Errors in altitude keeping must be symmetric about a mean of 0 ft (0 m), must have a standard deviation (SD) not greater than 43 ft (13 m), and the error
Appendix D D-2 frequency should decrease with increasing error magnitude at a rate that is at least exponential.
D.1.4 ICAO Doc. 9574 recognized specialist study groups would develop the detailed specifications to ensure the TVE objectives can be met over the full operational envelope in Reduced Vertical Separation Minimum (RVSM) airspace for each aircraft group. In determining the breakdown of tolerances between the elements of the system, it was considered necessary to set system tolerances at levels recognizing the overall objectives must be met operationally by aircraft and equipment subject to normal production variability, including the airframe SSE, and normal in-service degradation. It was also recognized that it would be necessary to develop specifications and procedures covering the means for ensuring in-service degradation is controlled at an acceptable level.
D.1.5 Based on studies reported in ICAO Doc. 9536, Review of the General Concept of Separation Panel (RGCSP), Volume 2, ICAO Doc. 9574 recommended the required margin between operational performance and design capability should be achieved by ensuring the performance requirements are developed to fulfill the following requirements, where the narrower tolerance in paragraph D.1.5.2 is specifically intended to allow for some degradation with increasing age:
D.1.5.1 The mean uncorrected residual position error static source error (SSE) of the group will not exceed ±80 ft (±25 m);
D.1.5.2 The sum of the absolute value of the ASEmean for the group and ASE3 SD within the group will not exceed 200 ft (60 m);
D.1.5.3 Each individual aircraft in the group will be built to have ASE contained within ±200 ft (±60 m); and D.1.5.4 An automatic altitude control system will be required and will be capable of controlling altitude within a tolerance band of ±50 ft (±15 m) about commanded altitude when operated in the altitude hold mode in straight and level flight under nonturbulent, nongust conditions.
D.1.6 These standards provide the basis for the separate performance aspects of airframe, altimetry, altimetry equipment, and automatic altitude control system. It is important to recognize the limits are based on studies (ICAO Doc. 9536, Volume 2) which showed ASE tends to follow a normal distribution about a characteristic mean value for the aircraft group. Therefore, the document should provide controls precluding the possibility individual aircraft approvals could create clusters operating with a mean significantly beyond 80 ft (25 m) in magnitude, such as could arise where elements of the altimetry system generate bias errors additional to the mean corrected SSE.
Appendix E APPENDIX E. RVSM AUTHORIZATION OVERVIEW £.1 RVSM Authorization Process Overview.
RVSM Authorization Flow Chart Determine which CHDO/IFO to application submit Amendment to an existing RVSM-Elements changing. authorization? No other New authorization based on one or more existing RVSM- Element? New authorization not based on any existing RVSM- Element?
para. 4.1 Determine if Yes reduest is tor amendment or new authorization para. 4.2 RVSM Authorization RVSM Authorization RVSM Authorization Group I Group II Group III para. 4.2.1 para. 4.2.2 para. 4.3.3 State which administrative change is occuring
e.g. Identify appropriate Identify appropriate
- Change of Primary Business Address Operator
- Change in Responsible Person/POC para. 3.4
- N-number change (existing acft.
- Remove airoraft from authorization statement no RVSM Make positive Elements are Provide complete documentation tor any RvSM-elements not dacumentation of Provide complete changing para. 3.2 - - RVSM-Compliant Aircraft; or previously accepted by FAA: Airoraft(s) para. 3.2 RVSM-Compliant
- RVSM-Knowledgeable Pilots Request issuance of Make positive Provide complete an amended RVSM statement for any RVSM-Elements documentation for previously accepted RVSM-Knowledgeable by the FAA para. 3.2 Pilots para. 3.:
Provide further information if Request issuance of a Request issuance of a requested new RVSM auinoraeton authorization Sign authorization upon receipt Provide further Provide further information if information if requested requested Sign authorization Sign authorization upon receipt E-1
Advisory Circular Feedback If you find an error in this AC, have recommendations for improving it, or have suggestions for new items/subjects to be added, you may let us know by emailing this form to RVSM@faa.gov.
Subject: AC 91-85A, Authorization of Aircraft and Operators for Flight in Reduced Vertical Separation Minimum (RVSM) Airspace Date: _____________________ Please check all appropriate line items:
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______________________________________________________________________ ______________________________________________________________________ ☐ In a future change to this AC, please cover the following subject:
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