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RVSM DECISION MATRIX
b. Further specifically states previously accepted RVSM-Knowledgeable Pilots requirements will be used with respect to the operation of the proposed approved RVSM Aircraft in RVSM airspace, as applicable;
c. Provides such additional information as necessary to evidence compliance with new or different RVSM-Knowledgeable Pilots requirements (or to be able to gain such approvals); and
d. Asks for the issuance of an RVSM authorization applying to the operation of the aircraft by that proposed RVSM Operator.
3. Provide such further information as the FSDO, CHDO, or IFO may request in order to efficiently process the request.
II. C. Applicable Procedures to be Followed by the Responsible FSDO, CHDO, or IFO
1. Review the request and supporting documentation received from the RVSM authorization applicant to determine if it appears the requested RVSM authorization is warranted.
2. To the extent the RVSM applicant has provided written documentation evidencing the Operator will be using a previously accepted RVSM Authorization Element, and accept that RVSM Authorization Element as a valid basis for the issuance of the new RVSM authorization, and to the extent the applicant has presented a proposed RVSM Authorization Element not previously reviewed and accepted, conduct such additional review and research with respect to that RVSM Authorization Element only as is required to issue the new RVSM authorization.
3. If an RVSM applicant has made a written affirmation one or more of the underlying previously accepted RVSM Authorization Elements have not changed or will not change, there is no other information provided to the FSDO, CHDO, or IFO raising any questions or concerns with respect to the on-going validity or applicability of those RVSM Authorization Elements, and the applicant has otherwise presented sufficient evidence of compliance with the requirements of the remaining RVSM Authorization Elements, then, subject to paragraph 2.4.4, the FSDO, CHDO, or IFO should issue the requested amendment without further inspections being required.
AUTHORIZATION GROUP III:
RVSM AUTHORIZATION NOT BASED ON
ONE OR MORE EXISTING RVSM AUTHORIZATION ELEMENTS In the event a proposed new or existing approved RVSM Operator seeks the issuance of an RVSM authorization not based on any existing RVSM Authorization Element, then neither Authorization Group I nor II above will apply, the applicant should submit sufficient evidence to show its ability to comply with each of the RVSM Authorization Elements, and the FSDO, CHDO, or IFO should process the request as a new and unique request by reviewing all of the materials provided by the applicant to ensure each of the RVSM Authorization Elements have been met.
5-1 CHAPTER 5. FAA REVIEW AND EVALUATION OF RVSM APPLICATIONS.
5.1 What is the General Process the FAA will Follow Upon Submission of the Request for an RVSM Authorization or Amended Authorization? Once application is made, the FAA will begin the process of review and evaluation of the documentation submitted.
When the FAA determines the airworthiness and operational requirements of the application are met, the FAA will proceed with issuing the authorization.
5.2 What are the Applicable Forms of the RVSM Authorization Documents?
5.2.1 Parts 121, 125, and 135 Operators. Authorization for parts 121, 125, and 135 Operators to operate in RVSM airspace should be granted through the issuance of an OpSpec paragraph from Part B (En Route Authorizations, Limitations, and Procedures) and Part D (Aircraft Authorization). Each aircraft for which the Operator is granted authority should be listed in the OpSpecs. Authorization to conduct RVSM operations in an RVSM area of operations new to the Operator should be granted by adding the Part B RVSM OpSpecs paragraph number to the appropriate area of operations in the Part B paragraph:
Authorized Areas of En Route Operation Limitations and Procedures.
5.2.2 Part 129 Operators. The operational authorization of RVSM for part 129 is provided by the State of the Operator. OpSpec A003 is used to confirm that the foreign air carrier has operational approval. The State of the Operator must have regulation and supporting guidance documents for the issuance of RVSM. The following are examples of guidance documents the FAA considers to be consistent with ICAO standards on RVSM.
5.2.2.1 The current edition of this advisory circular (AC) (91 85, Authorization of Aircraft and Operators for Flight in Reduces Vertical Separation Minimum Airspace); and Joint Aviation Authority (JAA) Temporary Guidance TGL-6.
Note: For part 129 Operators, inspector guidance for paragraph A003 is contained in FAA Order 8900.1, Volume 12, Chapter 2, Section 3.
5.2.3 Part 91K Operators. Part 91K Operators’ authorization to operate in RVSM airspace should be granted through the issuance of an MSpecs paragraph from Part B and Part D.
Each aircraft for which the Operator is granted authority should be listed in MSpecs.
Authorization to conduct RVSM operations in an RVSM area of operations new to the Operator should be granted by adding the Part B RVSM MSpecs paragraph number to the appropriate area of operations in the Part B paragraph.
5.2.4 Parts 91 and 125 (LODA Holder) Operators. Part 91 Operators and part 125 Operators holding a LODA should be issued a LOA when the initial authorization process has been completed.
Note: LODA is a formal authorization issued by the FAA CHDO, authorizing a deviation from specified sections of part 125 and identified in WebOPSS (125M database) as an A125 LODA operator.
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5.2.5 LOA Exemptions. Operators issued OpSpecs are not required to obtain an LOA for those operations conducted under part 91 provided that:
1. The aircraft is operated under the Operator name listed on the OpSpecs.
2. The flight is conducted in an area of operations listed in the OpSpecs.
3. The aircraft is operated under the conditions under which the OpSpecs were granted (e.g., if the Operator holds 121 or 135 OpSpecs, then the pilots used for the part 91 operation must have received part 121 or 135 training.)
4. Each part 91 operation, not associated with a certificated operator, will need a LOA to operate in RVSM airspace.
5.3 What are the Conditions That Would Require the Removal of an RVSM Authorization?
Note: Examples of reasons for amendment, revocation, or restriction of RVSM authorization include, but are not limited to, the reasons listed in part 91 appendix G, section 7.
5.3.1 Height-Keeping Errors. The incidence of height-keeping errors tolerated in an RVSM environment is very small. It is incumbent upon each operator to take immediate action to rectify the conditions causing the error. The operator should also report the event to the FAA within 72 hours with initial analysis of causal factors and measures to prevent further events. The FAA should determine the requirement for follow-up reports. Errors which should be reported and investigated are: Total Vertical Error (TVE) equal to or greater than ±300 ft (±90 m), ASE equal to or greater than ±245 ft (±75 m), and assigned altitude deviation (AAD) equal to or greater than ±300 ft (±90 m).
5.3.2 Error Categories. Height-keeping errors fall into two broad categories: 1) errors caused by malfunction of aircraft equipment, and 2) operational errors. An operator who commits one or more error(s) of either variety may be required to forfeit authority for RVSM operations. If a problem is identified related to one specific aircraft type, then RVSM authority may be removed for the operator for that specific type.
5.3.3 Effective, Timely Response. The operator should make an effective, timely response to each height-keeping error. The FAA may consider removing RVSM operational authorization if the operator response to a height-keeping error is not effective or timely.
The FAA should also consider the operator’s past performance record in determining the action to take. If an operator shows a history of operational and/or airworthiness errors, then authorization may be removed until the root causes of these errors are shown to be eliminated and RVSM programs and procedures are shown to be effective. The FAA will review each situation on a case-by-case basis.
5.3.4 Review Relevant OpSpec/MSpec/LOA Paragraphs. Operators may also consider reviewing all relevant paragraphs of their respective OpSpec, MSpec, or LOA
(e.g., A001) for other reasons which may affect RVSM authorizations.
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5.4 What Happens if I Change RVSM Equipment After Operational Authorization has been Granted? Any change to an RVSM Critical Component or RVSM System as defined in the initial application must be reported to the responsible office for evaluation.
The responsible office will determine if the aircraft is RVSM compliant.
Appendix A A-1 APPENDIX A. RVSM AIRWORTHINESS CERTIFICATION
CONTENTS Paragraph Page
A.1 IntroductionA-2
A.2 RVSM Flight EnvelopesA-4
A.3 Group and Non-Group AircraftA-6
A.4 Aircraft Systems—Group and Non-Group AircraftA-6
A.5 Altimetry System PerformanceA-9
A.6 Aircraft System Configurations: Older “Legacy” AirframesA-11
A.7 Altimetry System Performance SubstantiationA-14
A.8 Altimetry System Component Error BudgetA-16
A.9 Establishing and Monitoring Static Source ErrorsA-24
A.10 Maintenance RequirementsA-27
A.11 RVSM Airworthiness ApprovalA-30
Appendix A A-2 A.1 Introduction.
A.1.1 General. This Appendix provides guidance on the aircraft airworthiness certification process for Reduced Vertical Separation Minimum (RVSM) compliance. Key elements necessary to substantiate the aircraft systems performance required for RVSM certification are summarized. Differences between a Group and Non-Group aircraft certification program are presented. A comprehensive discussion of altimetry system error (ASE) and ASE variation is also provided.
Note: For additional information on obtaining RVSM airworthiness certification contact the appropriate FAA Field Office serving your geographic area for guidance. Contact information for Aircraft Certification Offices (ACO) can be found on the FAA Web site at www.faa.gov.
A.1.2 Definitions.
1. Aircraft Group. A group of aircraft of nominally identical design and build with respect to all details that could influence the accuracy of height-keeping performance.
2. Air Data Sensor. Line replaceable units designed to detect air data characteristics (e.g., pressure, temperature, etc.) to support the air data system of the aircraft.
3. Air Data System. Systems used to collect and process air data characteristics from various sensors to compute critical air data parameters (e.g., altitude, airspeed, height deviation, and temperature) for use by the pilot and other systems in the aircraft.
4. Altimetry System Error (ASE). The difference between the pressure altitude displayed to the flightcrew when referenced to International System of Units (SI) standard ground pressure setting (29.92 in. Hg/1013.25 hPa) and free stream pressure altitude.
5. Assigned Altitude Deviation (AAD). The difference between the altitude transmitted by a Mode C transponder and the assigned altitude/flight level (FL).
6. Automatic Altitude Control System. Any system designed to automatically control the aircraft to a referenced pressure altitude.
7. Avionics Error. The error in the processes of converting the sensed pressure into an electrical output, of applying any static source error correction (SSEC) as appropriate, and of displaying the corresponding altitude.
8. Basic RVSM Envelope. The range of Mach numbers and gross weights within the altitude ranges FL 290 to FL 410 (or max available altitude) where an aircraft is expected to operate most frequently.
Appendix A A-3
9. Derivative Aircraft. Aircraft of the same model type, certified under the same type certificate (TC). The aircraft may have different exterior dimensions, such as fuselage length and wing span, but share the same altimetry system architecture. In addition, derivative aircraft share the same SSEC at RVSM flight levels. In most cases, derivative aircraft will have differing flight envelopes, so the RVSM flight envelope defined for the Group must be carefully constructed such that the performance of all models within the Group is captured.
10. Full RVSM Envelope. The entire range of operational Mach numbers, W/δ, and altitude values over which the aircraft is operated within RVSM airspace.
11. Height-Keeping Capability. Aircraft height-keeping performance expected under nominal environmental operating conditions with proper aircraft operating practices and maintenance.
12. Height-Keeping Performance. The observed performance of an aircraft with respect to adherence to a flight level.
13. Instruction for Continued Airworthiness (ICA). Documentation giving instructions and requirements for the maintenance essential to the continued airworthiness of an aircraft.
14. Non-Group Aircraft. An aircraft for which the operator applies for approval on the characteristics of the unique airframe rather than on a group basis.
15. Residual Static Source Error (SSE). The amount by which SSE remains undercorrected or overcorrected after application of an SSEC.
16. Reduced Vertical Separation Minimum (RVSM). Designated airspace, typically between FL 290 and FL 410, where 1000’ vertical separation between aircraft is applied. This airspace is considered special qualification airspace.
17. Static Source Error (SSE). The difference between the pressure sensed by the aircraft static source and the undisturbed ambient pressure.
18. Static Source Error Correction (SSEC). A correction applied to the altimetry system to produce minimal residual SSE.
19. Total Vertical Error (TVE). Vertical geometric difference between the actual pressure altitude flown by an aircraft and its assigned pressure altitude (FL).
20. Worst Case Avionics. The combination of tolerance values, specified by the manufacturer for the altimetry fit into the aircraft, which gives the largest combined absolute value of avionics errors.
21. W/δ. Aircraft weight, W, divided by the atmospheric pressure ratio, δ.
Appendix A A-4 A.1.3 An Explanation of W/δ.
A.1.3.1 Throughout this Appendix, there are multiple references to the performance parameter W/δ. The following discussion is provided for the benefit of readers who may not be familiar with the use of this parameter.
A.1.3.2 It would be difficult to show all of the gross weight, altitude, and speed conditions constituting the RVSM envelope(s) on a single plot. This is because most of the speed boundaries of the envelopes are a function of both altitude and gross weight. As a result, a separate chart of altitude vs. Mach would be required for each aircraft gross weight. Aircraft performance engineers commonly use the following technique to solve this problem.
A.1.3.3 For most aircraft with RVSM altitude capability, the required flight envelope can be collapsed to a single chart, with good approximation, by use of the parameter W/δ (weight divided by atmospheric pressure ratio). This fact is due to the relationship between W/δ and the fundamental aerodynamic variables M and lift coefficient as shown below.
W/δ =1481.4 CL M2 SREF where δ = ambient pressure at flight altitude divided by sea level standard pressure of 29.92126 inches Hg.
W/δ = Weight over Atmospheric Pressure Ratio.
CL = Lift Coefficient (CL = L/qSREF).
L = Lift (in cruise flight L is equal to W).
q = Dynamic Pressure, q = 1481.4M2 δ.
Dynamic pressure is in the form of lbs/ft2.
M = Mach number.
SREF = Reference Wing Area in square feet.
W is the weight in pounds.
A.1.3.4 As a result, the flight envelope may be collapsed into one chart by simply plotting W/δ, rather than altitude, versus Mach number. Since δ is a fixed value for a given altitude, weight can be obtained for a given condition by simply multiplying the W/δ value by δ.
A.1.3.5 Over the RVSM altitude range, it is an accurate approximation to assume that position error is uniquely related to Mach number and W/δ for a given aircraft.
Appendix A A-5 A.2 RVSM Flight Envelopes.
A.2.1 General. For the purposes of RVSM approval, the aircraft flight envelope is considered in two parts: 1) the full RVSM envelope, and 2) the basic RVSM envelope. The basic RVSM envelope is the part of the flight envelope where aircraft operate the majority of time. The full RVSM envelope is the entire range of operational Mach numbers, W/δ, and altitude values over which the aircraft is operated within RVSM airspace. In general, the full RVSM envelope comprises parts of the flight envelope where the aircraft operates less frequently and where a larger ASE tolerance is allowed.
A.2.2 Full RVSM Envelope. The full RVSM envelope will comprise the entire range of operational Mach number, W/δ, and altitude values over which the aircraft can operate within RVSM airspace. Table A.2-1 establishes the parameters to consider.
Table A.2-1. Full RVSM Envelope Boundaries Lower Boundary is defined by:
Upper Boundary is defined by:
Altitude FL 290 The lower of the following:
• FL 410
• Airplane maximum certified altitude
• Altitude limited by: cruise thrust; buffet; other aircraft flight limitations Mach or Speed The lower of the following:
• Maximum endurance (holding) speed
• Maneuver speed The lower of the following:
• MMO/VMO (maximum operating speed (Mach/velocity))
• Speed limited by: cruise thrust; buffet; other aircraft flight limitations Gross Weight The lowest gross weight compatible with operation in RVSM airspace The highest gross weight compatible with operation in RVSM airspace A.2.3 Basic RVSM Envelope. The boundaries for the basic RVSM envelope are the same as those for the full RVSM envelope except in regard to the upper Mach boundary.
A.2.3.1 For the basic RVSM envelope, the upper Mach boundary may be limited to a range of airspeeds over which the aircraft Group can reasonably expect to operate most frequently. The manufacturer or design organization should define this boundary for each aircraft Group. It may be defined as equal to the upper Mach/airspeed boundary defined for the full RVSM envelope or a specified lower value. This lower value should not be less than the Long
Appendix A A-6 Range Cruise Mach number plus .04 Mach unless limited by available cruise thrust, buffet, or other aircraft flight limitations.
A.2.3.2 Long Range Cruise Mach number is the Mach for 99 percent of best fuel mileage at the particular W/δ under consideration.
A.3 Group and Non-Group Aircraft.
A.3.1 Group Aircraft. Aircraft comprising a Group must be of nominally identical design and build with respect to all details that could influence the accuracy of the height-keeping performance. The following conditions should be met:
1. Aircraft should be approved by the same TC, TC amendment, or Supplemental Type Certificate (STC), as applicable.
2. For derivative aircraft, it may be possible to use the database from the parent configuration to minimize the amount of additional data required to show compliance. The extent of additional data required will depend on the nature of the changes between the parent aircraft and the derivative aircraft.
3. The static system of each aircraft should be installed in a nominally identical manner and position. The same SSEC should be incorporated in all aircraft of the Group.
4. The avionics units installed on each aircraft to meet the minimum RVSM equipment requirements (paragraph A.4) should be manufactured to the manufacturer’s same specification, and have the same equipment part number and software part number (or version and revision).
Note: Aircraft which have avionic units which are of a different manufacturer or equipment part number, software part number (or version and revision) may be considered part of the Group if the applicant demonstrates to the appropriate FAA office this standard of avionic equipment provides identical or better system performance.
5. The airframe manufacturer or design organization produced or provided the RVSM data package.
A.3.2 Non-Group Aircraft. If an airframe does not meet the conditions of paragraph A.3.1 to qualify as a member of a Group or is presented as an individual airframe for approval, then it must be considered as a Non-Group aircraft for the purposes of RVSM approval.
A.4 Aircraft Systems—Group and Non-Group Aircraft.
A.4.1 Equipment for RVSM Operations. The minimum equipment fit should be as presented below. Additional examples of aircraft systems found on older, “legacy” airframes are presented in paragraph A.6.
Appendix A A-7 A.4.1.1 Two Independent Altitude Measurement Systems. Each system should be comprised and configured with the following elements:
A.4.1.1.1 Static Sources. Cross-coupled static source/system, provided with ice protection if located in areas subject to ice accretion.
A.4.1.1.2 Altitude Display. Equipment for measuring static pressure sensed by the static source, converting it to pressure altitude and displaying the pressure altitude to the flightcrew.
A.4.1.1.3 Altitude Reporting. Equipment for providing a digitally coded signal corresponding to the displayed pressure altitude, for automatic altitude reporting purposes. The pressure altitude from which the signal is derived must meet the requirements of paragraphs A5.2.1 and A5.2.2, or A5.3.2, as appropriate.
A.4.1.1.4 Altimetry System Components. The altimetry system should comprise all those elements involved in the process of sampling free stream static pressure and converting it to a pressure altitude output. The elements of the altimetry system fall into two main groups:
• Airframe plus static sources (pitot-static probe/static port), including the area around the static sources in the system design that must be maintained.
• Avionics and/or instruments.
A.4.1.1.5 Altimetry System Accuracy. The total altimetry system accuracy should satisfy the requirements of paragraphs A.5.2.1 and A.5.2.2, or A.5.3.2, as appropriate.
A.4.1.1.6 Static Source Error Correction (SSEC). If the design and characteristics of the aircraft and altimetry system are such that the standards of paragraphs A.5.2.1 and A.5.2.2, or A.5.3.2, are not satisfied by the location and geometry of the static sources alone, then suitable SSEC should be applied automatically within the avionic part of the altimetry system. The design aim for SSEC, whether aerodynamic/geometric or avionic, should be to produce a minimum residual SSE, but in all cases it should lead to satisfaction of the standards of paragraphs A.5.2.1 and A.5.2.2, or A.5.3.2, as appropriate.
A.4.1.1.7 Output to the Automatic Altitude Control and Altitude Alert Systems. The altimetry system equipment fit should provide reference signals for automatic altitude control and alerting at selected altitude. These signals should be derived from an altitude measurement system meeting the full requirements of Appendix A. The output may be used either directly or combined with other sensor signals. If SSEC is necessary in order to satisfy the requirements of paragraphs A.5.2.1 and A.5.2.2, or A.5.3.2, then an
Appendix A A-8 equivalent SSEC must be applied to the altitude control output. The output may be an altitude deviation signal, relative to the selected altitude, or a suitable absolute altitude output. Whatever the system architecture and SSEC system, the difference between the output to the altitude control system and the altitude displayed must be minimal.
A.4.1.1.8 System Safety Analysis. During the RVSM approval process, it must be verified analytically that the predicted rate of occurrence of undetected altimetry system failures does not exceed 1 x 10-5 per flight hour. All failures and failure combinations whose occurrence would not be evident from cross-flight deck checks, and which would lead to altitude measurement/display errors outside the specified limits, need to be assessed against this budget. No other failures or failure combinations need to be considered.
A.4.1.1.9 Air Data Systems and Configurations with Multiple Static Source Inputs.
Many aircraft are produced with air data systems making use of three or more static source inputs, and/or three or more air data computers (ADC).
Such systems (often referred to as “triplex” systems or “voting” schemes) are designed with integrated algorithms that monitor and compare the pressures sensed at the static sources. Sources providing “good” pressure values are used in the calculation of corrected altitude. Such configurations are acceptable provided at least two air data systems meet the requirements of paragraphs A4.1.1.1 through A4.1.1.8. Upon failure of one air data system, a second system must remain fully functional in compliance with the requirements of paragraphs A4.1.1.1 through A4.1.1.8.
A.4.1.2 One Secondary Surveillance Radar (SSR) Altitude Reporting Transponder. Any transponder meeting or exceeding the requirements of Technical Standard Order (TSO) C74( ) or TSO C112( ), as applicable, in accordance with the operational regulations under which the airplane is approved.
• An aircraft may be equipped with one or more transponders. If only one is fitted, it should have the capability for switching to obtain input from either altitude measurement system.
A.4.1.3 An Altitude Alert System. The altitude alert system should be capable of operation from either of the two required independent altitude measurement systems. The altitude alert system may be comprised of one or more line replaceable units (LRU), or it may be an integral part of a flight management system or flight management computer.