Appendix 2
A2-22 and/or CDI/map scaling requirements).
(c) The criteria used for the demonstration of the system, acceptable normal and non-normal procedures, the demonstrated configurations, type of facilities used, and any constraints or limitations necessary for safe operation.
(d) Define all the assumptions on systems external to the aircraft (e.g., signal in space performance, coverage, and survey accuracy).
(2) If compliance to the continuity requirements has been shown through a combination of navigation sensors, the AFMS/RFMS should contain a statement that “Continuity of RNP navigation has been demonstrated only where the operational environment supports all of the following types of sensors: <insert type of sensors for which credit is being sought>.
d. Flight Technical Error (FTE).
The aircraft manufacturer should verify maintenance of FTE (95% of the flying time) during straight and curved path segments per table 2-6 in RTCA/DO-283A. The FTE should be demonstrated in each phase of flight and each autopilot mode.
e. Interface to FGS.
Verify acceptable autopilot response to an RNP fault by pulling the circuit breaker for the RNP equipment. The aircraft manufacturer should complete this test in each of the RNP and autopilot modes, as applicable.
Appendix 3
Appendix 3. RNP Advanced Features.
A3-1. Introductio
n.
This appendix provides guidance on the performance and functional requirements for RNP systems containing radius to fix capability. This appendix does not apply to RNP AR; see appendix 2 for all RNP AR guidance.
A3-2. Radius to Fix Leg Capability.
RF legs are an optional capability rather than a minimum requirement for RNP operations.
This capability can be used in the initial, intermediate, and missed approach segments of instrument approaches, RNP DPs and RNP STARS. Additional information on RF legs may be found in the Aeronautical Information Manual. For RNP systems incorporating RF Leg capability, the systems must comply with the criteria in chapter 8 for RNP Approach, and chapter 9 for RNP 1 (terminal).
Note: RF legs will not be used in the final approach segment of an RNP approach.
a. System Requirements.
(1) Path Definition.
The RNP lateral accuracy requirement is evaluated around the path defined by the published procedure and RTCA/DO-236B, paragraph 3.2.3.3.
Note 1: Industry standards for paths can be found in RTCA/DO-236B.
Note 2: The guidance in this paragraph clarifies the intent in AC 90-105 for RNP Advanced Features. AC 90-105 mistakenly references RTCA/DO-236B paragraphs
3.2.5.4.1, Fly-By Transitions, and 3.2.5.4.2, Fixed-Radius Transitions, rather than paragraph 3.2.3.3, RF legs.
(2) Demonstration of Path Steering Performance.
The navigation system must have the capability to execute leg transitions and maintain tracks consistent with an RF leg between two fixes. There is no requirement for the aircraft to include a redundant navigation capability to perform RF legs should a loss of navigation occur during the RF leg. However, TC or STC applicants for RNP approval that include RF legs are encouraged to provide a redundant navigation capability on the aircraft that can maintain the RF leg track.
Note: The AFM/RFM or aircraft qualification guidance should document limitations if: 1) the aircraft cannot A3-1
Appendix 3
proceed “Direct-To” the initial fix defining an RF leg segm ent, 2) the aircraft cannot accept a radar vector (a heading assigned by ATC) to the middle of an RF leg segment for intercepting and completing the RF leg segment from that point while sustaining the desired level of performance.
(3) Flight Technical Error (FTE).
System documentation should support maintenance of FTE (95 percent of the flying time) during straight and curved path segments, for each phase of flight and each autopilot and/or FD mode requested. If using FTE values other than those listed in RTCA/DO-283A, the applicant must complete the demonstration in accordance with AC 120-29A, paragraphs 5.19.2.2 and 5.19.3.1.
Note: The applicant may use AC 120-29A, paragraphs
5.19.2.2 and 5.19.3.1 to compute accepted FTE values.
(4) Interface to FGS.
An acceptable autopilot and/or FD response to an RNP system failure or loss must be verified in each autopilot and FD mode, as applicable.
Note: If autopilot malfunction testing was performed for worst case failures, no further validation is required. In this case, the aircraft or equipment manufacturer must provide a statement of confirmation.
(5) Failure Modes/Annunciation.
System documentation should identify any failure modes potentially affecting RNP system RF Leg capability. Failure modes may include loss of electrical power, loss of signal reception, and RNP equipment failure, including navigation performance degradation, resulting in a loss of RNP containment integrity. The applicant should verify that a visible alert occurs within the flightcrew’s primary field of view when loss of navigation capability and/or loss of integrity are experienced.
b. Functional Requirements.
(1) Autopilot and Flight Director.
RNP procedures with RF legs require using an autopilot or FD with at least “roll-steering” capability that is driven by the RNP system. The autopilot/FD must operate with suitable accuracy to track the lateral and, as appropriate, vertical paths required by a specific RNP procedure.
A3-2
Appendix 3
A3-3
(2) Bank Angle.
The flight management computer, the FD system, and the autopilot must be capable of commanding a bank angle up to 25 degrees above 400 feet AGL.
(3) Electronic Map Display.
The aircraft must have an electronic map display depicting the RNP computed path of the selected procedure including RF legs.
(4) Maintaining LNAV in Missed Approach.
If abandoning a procedure while on an RF Leg or initiating a go-around or missed approach (through activation of TOGA or other means), the flight guidance mode should remain in LNAV to enable deviation and positive course guidance display during an RF leg. If the aircraft does not provide this capability, crew procedures must be used that assure the aircraft will adhere to the specified flight path during the RF Leg segment.
Note: For missed approaches with an RF Leg, the flightcrew must be able to couple the autopilot or FD to the RNP system (engage LNAV) by 500 feet AGL.
c. System Approval - Eligibility Airworthiness Documents.
The flight manual or referenced document should contain the following information:
(1) A statement indicating the aircraft meets the requirements for RNP operations with RF legs and has demonstrated the established minimum capabilities for these operations. This documentation should include the phase of flight, mode of flight (e.g., FD on or off and/or autopilot on or off; and applicable lateral and vertical modes), minimum demonstrated RNP value, and sensor limitations, if any.
(2) Any conditions or constraints on path steering performance should be identified
(e.g., autopilot engaged, FD with map display, including lateral and vertical modes, and/or CDI/map scaling requirements). Use of manual control with CDI only is not allowed on RF legs.
(3) The applicant should identify the criteria used for the system demonstration, acceptable normal and non-normal procedures, the demonstrated configurations, type of facilities used, and any constraints or limitations necessary for safe operation.
Appendix 4
Appendix 4. GNSS Velocity Tests to Support ADS-B.
A4-1. Introductio
n.
The information in this appendix describes a bench test procedure that can be used as an acceptable means to establish the velocity accuracy output of GNSS equipment.
A4-2. Velocity Accuracy and Velocity Figure of Merit Tests.
a. The following velocity tests are only required if the equipment manufacturer chooses to have their equipment provide inputs to ADS-B equipment.
b. AC 20-165, paragraph 7d, states that installations with a position source capable of providing velocity accuracy should have the navigation accuracy category - velocity (NACV) derived from the position source, and the velocity accuracy should be validated during the position source manufacturer’s certification testing. The following procedures, developed by RTCA SC-159, are one means of accomplishing this testing.
c. The purpose of the GNSS velocity accuracy test is to characterize the 95% horizontal and 95% vertical velocity accuracies during normal maneuvers as specified in RTCA/DO-229D, RTCA/DO-253C, and RTCA/DO-316 receiver MOPS for equipment intended to support either NACV =1 or NACV = 2. Test procedures for higher levels are expected to be developed as more demanding ADS-B applications mature.
d. The tests to verify velocity accuracy performance shall be run for each of the scenarios described below for all operating modes of the receiver where a valid position and/or velocity could be output by the receiver.
(1) It is possible that a given receiver may use a different velocity algorithm when computing an un-augmented GPS position solution versus computing a solution augmented with differential corrections. In that case, this test must be repeated for both the augmented and un-augmented modes of operation. Even in the case where the velocity algorithm is the same whether in un-augmented or augmented mode, there are still enough variables like the software path, inputs, outputs etc., that it is required to repeat the test.
(2) It is not required to repeat the test for different sub-modes of an un-augmented or augmented mode where the inputs, velocity algorithm and outputs are the same.
A4-3. Horizontal Velocity Accuracy Test Conditions Commensurate with NACV = 1.
a. Ensure the simulator scenario has enough GPS satellites to provide a horizontal dilution of precision (HDOP) of 1.5 or less.
b. One satellite shall be set at maximum power (including maximum combined satellite and aircraft antenna gain), and the other satellites shall be set at minimum power (including minimum antenna gain).
A4-1
Appendix 4
c. Broadband GNSS test noise (IGNSS,Test) of spectral density as defined in RTCA/DO-229D, paragraph 2.5.8, broadband external interference (Iext,test) and thermal noise contribution from the sky and the antenna (Nsky,antenna) shall be simulated.
Note: In RTCA/DO-229D, paragraph 2.5.8.2 step 2, replace -173.0 dBm/Hz with -172.8 dBm/Hz for total GNSS noise (IGNSS) when running separate GPS/SBAS testing for accuracy verification and/or GPS/SBAS message loss rate data.
d. The airborne equipment shall be initialized with the appropriate position and time. It is assumed that the receiver has obtained a valid almanac for the simulator scenario to be tested prior to conducting the test.
e. Platform dynamics for the horizontal velocity accuracy test shall be as defined in table 12 below.
Time (s) Start Jerk (g/s) End Jerk (g/s) From To Dynamics North East Down Total North East Down Total 0 T Static 0 0 0 0 0 0 0 0 T+1 T+71 0.58g longitudinal acceleration to 411 m/s
0.xx Note 1
0.xx Note 1 0 0.25 0.xx Note 1
0.xx Note 1 0 0.25 T+72 T+129 Straight un-accelerated flight 0 0 0 0 0 0 0 0 T+130 T+194 -0.45g longitudinal acceleration to 125 m/s
0.xx Note 1
0.xx Note 1 0 0.2 0.xx Note 1
0.xx Note 1 0 0.2 T+195 T+254 Straight un-accelerated flight 0 0 0 0 0 0 0 0 T+255 T+325 turn 180° with 0.58g lateral acceleration
0.xx Note 1
0.xx Note 1 0 0.25 0.xx Note 1
0.xx Note 1 0 0.25 T+326 T+420 Straight un-accelerated flight 0 0 0 0 0 0 0 0 Table 12. Platform Dynamics for Horizontal Velocity Accuracy Test
Note 1: The components of the jerk in the north and east direction depends on the heading chosen in the scenario.
The total jerk is not to exceed the vector combination of north, east, and down jerk components. The maximum total jerk to quickly achieve the desired dynamics should be used, but the jerk should not exceed the normal maneuver A4-2
Appendix 4
total jerk requirem ent of 0.25 g/s.
Note 2: The actual times may vary based on the simulator scenario control settings.
f. Signal and radio frequency interference (RFI) conditions can be modified during static period to aid acquisition. Ensure the receiver enters the desired operation mode before dynamics and appropriate signal and interference conditions are applied.
g. Use the simulator velocity truth data ( trutheast iV _ , truthnorthiV _ ) and the GNSS receiver velocity data ( east iV , northiV ) to determine the horizontal velocity error ih after the GNSS receiver has entered the desired navigation mode with the specified signal and RFI conditions:
2_2_ )()( northitruthnorthieastitrutheastii VVVVh
A4-4. Horizontal Accuracy Pass/Fail Determination.
a. The 95% horizontal velocity accuracy statistic shall be computed using the formula given below. The equipment shall pass if the statistic is less than or equal to 10-LSB m/s.
Note: The notation “10-LSB m/s” specifies that the pass threshold is 10 m/s minus the magnitude of the least significant bit of the output data fields representing the horizontal velocity components. The intent is to ensure that quantization error in the velocity output does not degrade the accuracy below the threshold.
N i i N i HDOP h 1 2
5.1 *2
Where:
hi = horizontal velocity error (m/sec).
HDOPi = horizontal dilution of precision at epoch i.
N = number of sample points used.
b. For this test, the number of samples shall include all samples where the receiver is in the desired navigation mode and when in motion.
Note: The minimum number of samples is 420 for a 1 Hz solution and 2100 for a 5 Hz solution (i.e., 5* 420).
A4-3
Appendix 4
A4-5. Horizontal Velocity Figure of Merit Pass/Fail Determination.
The receiver velocity data and the horizontal figure of merit - velocity (HFOMV) data shall be used to determine the percentage of samples bounded by the HFOMV as shown below. The test passes if TSh,b is greater than or equal to 0.95.
Vi Vi i h N i i hbh HFOM h HFOM hb N bNTS 0 1 samples of number 1 , 1 ,,
A4-6. Vertical Velocity Accuracy Test Conditions Commensurate with NACV = 1.
a. Ensure the simulator scenario has enough GPS satellites to provide a vertical dilution of precision (VDOP) of 3.0 or less.
b. One satellite shall be set at maximum power (including maximum combined satellite and aircraft antenna gain), and the other satellites shall be set at minimum power (including minimum antenna gain).
c. Broadband GNSS test noise (IGNSS,Test) of spectral density as defined in RTCA/DO-229D, paragraph 2.5.8, broadband external interference (Iext,test) and thermal noise contribution from the sky and the antenna (Nsky,antenna) shall be simulated.
Note: In RTCA/DO-229D, paragraph 2.5.8.2 step 2, replace -173.0 dBm/Hz with -172.8 dBm/Hz for total GNSS noise (IGNSS) when running separate GPS/SBAS testing for accuracy verification and/or GPS/SBAS message loss rate data.
d. The airborne equipment shall be initialized with the appropriate position and time.
It is assumed that the receiver has obtained a valid almanac for the simulator scenario to be tested prior to conducting the test.
e. Platform dynamics for the vertical velocity accuracy test shall be as defined in table 13 below.
A4- 4
Appendix 4
Time (s) Start Jerk (g/s) End Jerk (g/s) From To Dynamics North East Down Total North East Down Total 0 T Static 0 0 0 0 0 0 0 0 T+1 T+71 0.58g longitudinal acceleration to 411 m/s
0.xx Note 1
0.xx Note 1 0 0.25 0.xx Note 1
0.xx Note 1 0 0.25 T+72 T+130 Straight and level un-accelerated flight 0 0 0 0 0 0 0 0 T+131 T+131+X Climb, increasing the vertical climb rate from 0 to 21 m/s, then decrease the rate back to 0 m/s and repeat this increasing and decreasing pattern until the time out.
0 0 0.xx Note 1
0.25 0 0 0.xx Note 1
0.25 T+132+X T+192+X Straight and level un-accelerated flight 0 0 0 0 0 0 0 0 T+193+X T+193+2X Descend, increasing the vertical descent rate from 0 to 21 m/s, then decrease the rate back to 0 m/s and repeat this increasing and decreasing pattern until the time out.
0 0 0.xx Note 1
0.25 0 0 0.xx Note 1
0.25 T+194+2X T+274+2X Straight and level un-accelerated flight 0 0 0 0 0 0 0 0 Table 13. Platform Dynamics for Vertical Velocity Accuracy Test
Note 1: The components of the jerk in the north and east direction depends on the heading chosen in the scenario.
The total jerk is not to exceed the vector combination of north, east, and down jerk components. The maximum total jerk to quickly achieve the desired dynamics should be used, but the jerk should not exceed the normal maneuver total jerk requirement of 0.25 g/s.
Note 2: The actual times may vary based on the simulator scenario control settings.
Note 3: The value of X must be at least 63 seconds to have enough samples during vertical acceleration.
f. Signal and RFI conditions can be modified during the static period to aid acquisition. Ensure the receiver enters the desired operation mode before dynamics and A4-5
Appendix 4
appropriate signal and interference conditions are applied.
g. Use the simulator velocity truth data ( truthvertical iV _ ) and the GNSS receiver velocity data ( vertical iV ) to determine the vertical velocity error ( iv ) after the GNSS receiver has entered the desired navigation mode with the specified signal and RFI conditions:
vertical i truthvertical ii VVv _
A4-7. Vertical Velocity Accuracy Pass/Fail Determination.
a. The 95% vertical velocity accuracy statistic shall be computed using the formula given below. The equipment shall be considered pass only if the statistic is less than or equal to 50-LSB ft/s.
N i i N i VDOP v 1 2 3 *2
Where:
vi = vertical velocity error (ft/sec).
VDOPi = vertical dilution of precision at epoch i.
N = number of sample points used.
b. For this test, the number of samples shall include all samples where the receiver is in the desired navigation mode.
Note: The minimum number of samples is 420 for a 1 Hz solution and 2100 for a 5 Hz solution.
A4-8. Vertical Velocity Figure of Merit Pass/Fail Determination.
The receiver velocity data and the vertical figure of merit - velocity (VFOMV) data shall be used to determine the percentage of samples bounded by the VFOMV as shown below. The test passes if bvTS , is greater than or equal to 0.95.
Vi Vi iv N i ivbv VFOMv VFOMvb N bNTS 0 1 samples ofnumber 1 , 1 ,,
A4-6
Appendix 4
A4-7
A4-9. Additional Tests to Demonstrate Accuracy Commensurate with NACV = 2.
The following procedure is one acceptable means for equipment capable of better accuracy performance to demonstrate compliance with the horizontal velocity error requirement of less than 3 m/s.
a. Run the scenario in table 13 with all satellites set at high power and no RFI.
b. This accuracy evaluation shall only include those data samples collected during the acceleration period.
c. Find the particular ih (noted as accT ) so that 95% of ih samples are less than or equal to accT .
d. Re-run the scenario in table 13 with the same satellite and RFI conditions as the 10 m/s (NACV=1) test.
e. This time only the data samples during the non-acceleration period with the specified signal and RFI conditions are used.
f. Compute:
accnon N i accnoni accnoni accnon N HDOP h T accnon _ 1 2 __ __ _ _ 5.1 *2
Where:
accnoniHDOP __ and accnonN _ are the HDOP values for each sample i and the total number of samples (non-acceleration period), respectively.
g. The test passes only if accnonacc TT _ is less than or equal to 3-LSB m/s.
h. The velocity figure of merit is evaluated in the same way as for the 10 m/s test, i.e., the samples during acceleration and non-acceleration periods of the above 2 runs are evaluated together against the 0.95 threshold.
i. The vertical velocity requirement of 15 ft/s should be tested using the exact same philosophy as the test of 3 m/s above but with the scenario in table 13.
Appendix 5
Appendix 5. Sample Airplane/Rotorcraft Flight Manual Supplement.
A5-1. Introduction.
The intent of this appendix is to provide general guidance for creating an AFMS/RFMS.
The information and structure below are not intended to cover all possible aircraft integrations or equipment capabilities and should not be construed to limit the content included in an AFMS/RFMS. Actual AFMS/RFMS language and structure must be tailored to the actual installation, equipment capabilities, and limitations.
A5-8