Appendix C C-2 C.1.3 Guidance To The Pilot In The Event Of Equipment Failures Or Encounters With Turbulence After Entry Into RVSM Airspace (Including Expected ATC Actions).
C.1.3.1 The following material is provided with the purpose of giving the pilot guidance on actions to take under certain conditions of equipment failure and encounters with turbulence. It also describes the expected ATC controller actions in these situations. It is recognized the pilot and controller will use judgment to determine the action most appropriate to any given situation. The guidance material recognizes for certain equipment failures, the safest course of action may be for the aircraft to maintain the assigned flight level (FL) and route while the pilot and controller take precautionary action to protect separation. For extreme cases of equipment failure, however, the guidance recognizes the safest course of action may be for the aircraft to depart from the cleared FL or route by obtaining a revised ATC clearance; or if unable to obtain prior ATC clearance, executing the established ICAO Doc. 4444 and Doc. 7030 contingency maneuvers for the area of operation.
Note: Paragraph C.1.4 provides an expanded description of the scenarios detailed below.
C.1.3.2 Contingency Scenarios. The following paragraphs summarize pilot actions to mitigate the potential for conflict with other aircraft in certain contingency situations.
Figure C.1-1. Scenario 1 The pilot is: 1) unsure of the vertical position of the aircraft due to the loss or degradation of all primary altimetry systems; or 2) unsure of the capability to maintain cleared flight level (CFL) due to turbulence or loss of all automatic altitude control systems.
The pilot should: ATC can be expected to:
Maintain CFL while evaluating the situation;
Watch for conflicting traffic both visually and by reference to ACAS (TCAS), if equipped;
If considered necessary, alert nearby aircraft by:
1) Making maximum use of exterior lights;
2) Broadcasting position, FL, and intentions on 121.5 MHz (as a back-up, the VHF inter-pilot air-to-air frequency may be used).
Notify ATC of the situation and intended course of action. Possible courses of action include:
Obtain the pilot’s intentions and pass essential traffic information.
1) Maintaining the CFL and route, provided 1) If the pilot intends to continue in RVSM
Appendix C C-3 The pilot should: ATC can be expected to:
ATC can provide lateral, longitudinal, or conventional vertical separation.
airspace, assess traffic situation to determine if the aircraft can be accommodated through the provision of lateral, longitudinal, or increased vertical separation, and if so, apply the appropriate minimum.
2) Requesting ATC clearance to climb above or descend below RVSM airspace if the aircraft cannot maintain CFL and ATC cannot establish adequate separation from other aircraft.
2) If the pilot requests clearance to exit RVSM airspace, accommodate expeditiously, if possible.
3) Executing the ICAO Doc. 4444 contingency maneuver to offset from the assigned track and FL, if ATC clearance cannot be obtained and the aircraft cannot maintain CFL.
3) If adequate separation cannot be established and it is not possible to comply with the pilot’s request for clearance to exit RVSM airspace, advise the pilot of essential traffic information, notify other aircraft in the vicinity and continue to monitor the situation.
4) Notify adjoining ATC facilities/sectors of the situation.
Figure C.1-2. Scenario 2 There is a failure or loss of accuracy of one primary altimetry system (e.g., greater than 200 ft difference between primary altimeters).
The Pilot should:
Cross-check standby altimeter, confirm the accuracy of a primary altimeter system, and notify ATC of the loss of redundancy. If unable to confirm primary altimeter system accuracy, follow pilot actions listed in the preceding scenario.
C.1.4 Expanded Equipment Failure and Turbulence Encounter Scenarios. Operators may consider this material for use in training programs.
Appendix C C-4 Figure C.1-3. Expanded Scenario 1 All automatic altitude control systems fail (e.g., Automatic Altitude Hold).
The pilot should: ATC can be expected to:
Initially maintain CFL, and Evaluate the aircraft’s capability to maintain altitude through manual control.
Subsequently watch for conflicting traffic both visually and by reference to TCAS, if equipped.
If considered necessary, alert nearby aircraft by:
1) Making maximum use of exterior lights;
2) Broadcasting position, FL, and intentions on 121.5 MHz (as a back-up, the VHF inter-pilot air-to-air frequency may be used).
Notify ATC of the failure and intended course of action. Possible courses of action include:
1) Maintaining the CFL and route, provided the aircraft can maintain level.
1) If the pilot intends to continue in RVSM airspace, assess traffic situation to determine if the aircraft can be accommodated through the provision of lateral, longitudinal, or increased vertical separation, and if so, apply the appropriate minimum.
2) Requesting ATC clearance to climb above or descend below RVSM airspace if the aircraft cannot maintain CFL and ATC cannot establish lateral, longitudinal, or conventional vertical separation.
2) If the pilot requests clearance to exit RVSM airspace, accommodate expeditiously, if possible.
3) Executing the ICAO Doc. 4444 contingency maneuver to offset from the assigned track and FL, if ATC clearance cannot be obtained and the aircraft cannot maintain CFL.
3) If adequate separation cannot be established and it is not possible to comply with the pilot’s request for clearance to exit RVSM airspace, advise the pilot of essential traffic information, notify other aircraft in the vicinity, and continue to monitor the situation.
4) Notify adjoining ATC facilities/sectors of the situation.
Appendix C C-5 Figure C.1-4. Expanded Scenario 2 Loss of redundancy in primary altimetry systems.
The pilot should: ATC can be expected to:
If the remaining altimetry system is functioning normally, couple that system to the automatic altitude control system, notify ATC of the loss of redundancy, and maintain vigilance of altitude keeping.
Acknowledge the situation and continue to monitor progress.
Figure C.1-5. Expanded Scenario 3 All primary altimetry systems are considered unreliable or fail.
The pilot should: ATC can be expected to:
Maintain CFL by reference to the standby altimeter (if the aircraft is so equipped).
Alert nearby aircraft by:
1) Making maximum use of exterior lights;
2) Broadcasting position, FL, and intentions on
121.5 MHz (as a back-up, the VHF inter-pilot air-to-air frequency may be used).
Consider declaring an emergency. Notify ATC of the failure and intended course of action.
Possible courses of action include:
Obtain pilot’s intentions, and pass essential traffic information.
1) Maintaining CFL and route provided ATC can provide lateral, longitudinal, or conventional vertical separation.
1) If the pilot intends to continue in RVSM airspace, assess traffic situation to determine if the aircraft can be accommodated through the provision of lateral, longitudinal, or increased vertical separation, and if so, apply the appropriate minimum.
2) Requesting ATC clearance to climb above or descend below RVSM airspace if ATC cannot establish adequate separation from other aircraft.
2) If the pilot requests clearance to exit RVSM airspace, accommodate expeditiously, if possible.
3) Executing the ICAO Doc. 4444 contingency maneuver to offset from the assigned track and FL, if ATC clearance cannot be obtained.
3) If adequate separation cannot be established and it is not possible to comply with the pilot’s request for clearance to exit RVSM airspace, advise the pilot of essential traffic information, notify other aircraft in the vicinity, and continue to monitor the situation.
4) Notify adjoining ATC facilities/sectors of the situation.
Appendix C C-6 Figure C.1-6. Expanded Scenario 4 The primary altimeters diverge by more than 200 ft (60 m).
The pilot should:
Attempt to determine the defective system through established trouble-shooting procedures and/or comparing the primary altimeter displace to the standby altimeter (as corrected by the correction cards, if required).
If the defective system can be determined, couple the functioning altimeter system to the altitude keeping device.
If the defective system cannot be determined, follow the guidance in Scenario 3 for failure or unreliable altimeter indications of all primary altimeters.
Figure C.1-7. Expanded Scenario 5 Turbulence (greater than moderate) which the pilot believes will impact the aircraft’s capability to maintain FL.
The pilot should: ATC can be expected to:
Watch for conflicting traffic both visually and by reference to TCAS, if equipped.
If considered necessary, alert nearby aircraft by:
1) Making maximum use of exterior lights;
2) Broadcasting position, FL, and intentions on 121.5 MHz (as a back-up, the VHF inter-pilot air-to-air frequency may be used).
Notify ATC of intended course of action as soon as possible. Possible courses of action include:
1) Maintaining CFL and route provided ATC can provide lateral, longitudinal, or conventional vertical separation.
1) Assess traffic situation to determine if the aircraft can be accommodated through the provision of lateral, longitudinal, or increased vertical separation, and if so, apply the appropriate minimum.
2) Requesting flight level change, if necessary.
2) If unable to provide adequate separation, advise the pilot of essential traffic information and request pilot’s intentions.
Appendix C C-7 The pilot should: ATC can be expected to:
3) Executing the ICAO Doc. 4444 contingency maneuver to offset from the assigned track and FL, if ATC clearance cannot be obtained and the aircraft cannot maintain CFL.
3) Notify other aircraft in the vicinity and monitor the situation.
4) Notify adjoining ATC facilities/sectors of the situation.
C.1.5 Transponder Failure. The provider States will determine the specific actions ATC will take in the event of transponder failure in RVSM.
C.1.6 ICAO Regional Supplementary Procedures (SUPPS) and State Specific Guidance.
Operators are responsible for knowing the RVSM procedures in the areas of intended operation. Operators starting RVSM operation in an RVSM area of operation new to them should ensure their RVSM programs incorporate RVSM policy and procedures unique to the new area of operations.
C.1.6.1 Operators should review ICAO Document 7030, Regional Supplementary Procedures, and State Aeronautical Information Publications prior to starting RVSM operations in an area new to the operator.
C.1.7 Additional Information. Additional information regarding RVSM operations can be found on the FAA RVSM Documentation Web page at:
https://www.faa.gov/air_traffic/separation_standards/rvsm/documentation/.
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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