Appendix 4
A4-11. Test to Demonstrate Horizontal Position Accuracy Metric.
a. The following procedure is one acceptable means for equipment to demonstrate compliance with the 95% horizontal position accuracy output requirements needed to support ADS-B. This parameter is commonly called the horizontal figure of merit (HFOM) and should not be confused with the horizontal velocity figure of merit (HFOMV) from the velocity accuracy tests. TSO-C145/C146 revision ‘b/c’ and TSO-C196(AR) equipment already satisfy this parameter by meeting the TSO requirements. TSO-C145a/C146a and TSO-C129(AR) equipment should use this test to demonstrate the HFOM output.
b. The horizontal position output must be calculated using the general least squares position solution of DO-229D appendix J.1 (or any mathematically equivalent linear combination of range measurements). There is no restriction on the choice of the weight matrix W (including non-weighted solutions), and using the LNAV/VNAV, LP, LPV approach weight (wi = 1/σi2) is optional.
c. The horizontal position accuracy must be tested using the procedure of DO-229D section 2.5.8.3. The σi2 used to compute the variance d2major must be greater than or equal to those listed in appendix J when the equipment uses SBAS-provided integrity and greater than or equal to those listed as an acceptable means for FDE-provided integrity in section 2.1.2.2.2.2 when the equipment does not use SBAS-provided integrity. A fixed sigma of 33.3 m is considered a sufficient over-bound when using FDE-provided integrity. For equipment that uses SBAS-provided integrity, testing only in the highest mode attainable for its declared Operational Class as specified in the test itself is acceptable.
d. Performing the test described in paragraphs A4-11.a through A4-11.c confirms that the σi and dmajor, deast, and dnorth used to compute the HFOM accuracy metric provide a sufficient error over-bound. The accuracy metric must be greater than or equal to 1.96 sqrt(d2east + d2north) or 2.45 dmajor where dmajor, deast, and dnorth are computed using the same σi employed during the horizontal accuracy test procedure. This HFOM calculation does not require any specific additional testing.
Note 1: The scaling factors for the horizontal position accuracy metric can be rounded to 2 decimal places but there is no intention to prohibit the use of a more accurate number.
Note 2: The horizontal position accuracy metric listed above is the standard metric used to provide a minimum of 95% containment (varying from 95% to approximately
98.5%) under the assumption that a Gaussian distribution with a sigma of σi over-bounds the error of the range measurements. The use of a general least squares position solution (or mathematical equivalent) results in a jointly Gaussian distribution for the components (North, East, Up) of the position error. Any accuracy metric that can be mathematically demonstrated to provide a minimum 95% A4-10
Appendix 4
containm ent in the position domain under this Gaussian assumption is also acceptable.
A4-12. Demonstrating True Track Angle/True Track Angle Validity.
a. The true track angle/true track validity parameter is intended as a non-critical, optional parameter for airport surface operations. Since most GNSS position sources output some type of track information even during ground operations, it is recommended that GNSS manufacturers output ground track angle as the information can be useful for non-critical ADS- B surface applications. The concern is that below a certain velocity the ground track information becomes invalid, and the velocity at which this occurs is dependent upon the specific GNSS equipment design. GNSS/ADS-B integrations at the aircraft level must stop broadcasting ground track when the GNSS ground track information becomes invalid.
Note: It is possible that future ADS-B surface applications may be defined for critical functions. More stringent GNSS performance requirements and tests than what is described below will have to be developed if and when these new surface applications are defined.
b. GNSS equipment not providing a valid ground track.
GNSS manufacturers may choose to not have their equipment provide a ground track output acceptable for the ADS-B true track angle/true track validity parameter. GNSS manufacturers choosing this option need to include a statement within the equipment limitations section that the ground track information must not be used for ADS-B surface applications.
c. GNSS equipment providing a valid ground track for the true track angle/true track validity parameter.
(1) Appendix H in both RTCA/DO-229D and RTCA/DO-316 provides a recommended output for true ground track angle (ARINC 743 all revisions label 103) for those using ARINC 429 characteristics.
(2) GNSS manufacturers must indicate at what velocity the GNSS track angle 95% accuracy (derived from north/east velocity) exceeds eight degrees variance from the aircraft’s actual ground track. GNSS manufacturers must provide this data within the equipment installation instructions for the GNSS/ADS-B integrator.
(3) Optimally, the GNSS equipment will either invalidate or stop outputting the ground track information when it is no longer valid. If the sensor outputs a validity indicator for the velocity, it is sufficient to simply flag the output as invalid if the track accuracy exceeds eight degrees (95%). The GNSS manufacturer must provide information in the installation instructions describing how the sensor outputs the validity indicator if one is provided.
Alternately, it is acceptable for the GNSS manufacturer to state in the installation instructions that the track angle does not meet the required accuracy below a specified velocity and indicate the minimum acceptable velocity.
A4-11
Appendix 4
A4-12
(4) GNSS manufacturers developing data for the minimum valid velocity should consider the following assumptions:
Surface message is used during taxi, takeoff, and landing ground applications.
Surface taxi speed is less than 50 knots.
No turns; only along-track acceleration (0.58g) and jerk (0.25 g/sec).
Track angle validity is only an issue at taxi speeds.
Use the GNSS noise environment defined in the velocity test (paragraphs A4-3 through A4-8), or for sensors not originally certified to the latest noise environment standards, use a reduced environmental noise level as described in paragraphs A4-2.d(3) and A4-2d.(4).
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. AC 25.1581-1 provides flight manual guidance information for transport category airplanes.
A5-1
Appendix 5
Installation Center/Repair Station Model XXX GPS 123 Fourth Street Navigation System Anytown, USA
FAA APPROVED AIRPLANE FLIGHT MANUAL SUPPLEMENT
ABC MODEL XXX GPS NAVIGATION SYSTEM
AIRPLANE MAKE:
AIRPLANE MODEL:
AIRPLANE SERIAL NO.:
REGISTRATION NO.:
This document must be carried in the airplane at all times. It describes the operating procedures for the ABC Model XXX GPS navigation system when it has been installed in accordance with <manufacturer's installation manual number and date>.
For airplanes with an FAA approved airplane flight manual, this document serves as the FAA approved ABC Model XXX GPS flight manual supplement. For airplanes that do not have an approved flight manual, this document serves as the FAA approved ABC Model XXX GPS supplemental flight manual.
The information contained herein supplements or supersedes the basic airplane flight manual dated <insert date> only in those areas listed herein. For limitations, procedures, and performance information not contained in this document, consult the basic airplane flight manual.
FAA APPROVED
_____________________ Title Office Federal Aviation Administration City, State F A A A p p r o v e d P a g e < > o f < > Date: ________ A5-2
Appendix 5
Sample Airplane/Rotorcraft Flight Manual (Continued)
Installation Center/Repair Station Model XXX GPS 123 Fourth Street Navigation System Anytown, USA
Table of Contents
SectionPage
1 General.............................................< >
2 Limitations........................................< >
3 Emergency/Abnormal Procedures....< >
4 Normal Procedures...........................< >
5 Performance......................................< >
6 Weight and Balance..........................< >
7 System Description...........................< >
FAA Approved Page <> of <> Date: ________ A5-3
Appendix 5
Sample Airplane/Rotorcraft Flight Manual (Continued)
Installation Center/Repair Station Model XXX GPS 123 Fourth Street Navigation System Anytown, USA
SECTION 1 - GENERAL <Include the appropriate statement to describe the equipment capability:>
GPS TSO-C129<appropriate revision>: The installed ABC system complies with AC 20-138C for IFR navigation using GPS for enroute, terminal area, and non-precision approach operations. Non-precision approach operations include those based on conventional navigation aids with “or GPS” in the title and those with “GPS” and “RNAV(GPS)” in the title to “LNAV” minimums.
GPS/SBAS TSO-C145 or C146<appropriate revision> Class 3: The installed ABC equipment complies with AC 20-138C for navigation using GPS and GPS/SBAS (within the coverage of a satellite-based augmentation system complying with ICAO Annex 10) for enroute, terminal area, non-precision approach, and approach procedures with vertical guidance operations.
Non-precision approach operations include those based on conventional navigation aids with “or GPS” in the title and those with “GPS” and “RNAV(GPS)” in the title to “LNAV” and “LP” minimums. Approach procedures with vertical guidance includes “RNAV(GPS) to “LNAV/VNAV” and “LPV” minimums.
Note 1: TSO-C145a/C146a Class 3 equipment is not required to perform LP approaches.
Note 2: Functional Class Delta equipment is an “ILS look-alike” that only provides LP/LPV capability on the final approach segment.
GPS/SBAS TSO-C145 or C146<appropriate revision> Class 2: The installed ABC equipment complies with AC 20-138C for navigation using GPS and GPS/SBAS (within the coverage of a satellite-based augmentation system complying with ICAO Annex 10) for enroute, terminal area, non-precision approach, and approach procedures with vertical guidance operations.
Non-precision approach operations include those based on conventional navigation aids with “or GPS” in the title and those with “GPS” and “RNAV(GPS)” in the title to “LNAV” minimums. Approach procedures with vertical guidance includes “RNAV(GPS) to “LNAV/VNAV” minimums.
FAA Approved Page <> of <> Date: ________
A5-4
Appendix 5
Sample Airplane/Rotorcraft Flight Manual (Continued)
Installation Center/Repair Station Model XXX GPS 123 Fourth Street Navigation System Anytown, USA
GPS/SBAS TSO-C145 or C146<appropriate revision Class 1: The installed ABC equipment complies with AC 20-138C for navigation using GPS and GPS/SBAS (within the coverage of a satellite-based augmentation system complying with ICAO Annex 10) for enroute, terminal area, and non-precision approach operations. Non-precision approach operations include those based on conventional navigation aids with “or GPS” in the title and those with “GPS” and “RNAV(GPS)” in the title to “LNAV” minimums.
GPS/GBAS TSO-C161a<appropriate revision>: The installed ABC system complies with AC 20-138C for navigation using GPS and GPS/GBAS (within the coverage of a ground-based augmentation system complying with ICAO Annex 10) for GPS/GBAS precision approach procedures to “GLS” minimums.
GPS TSO-C196(AR): The installed ABC system complies with AC 20-138C for IFR navigation using GPS for enroute, terminal area, and non-precision approach operations. Non-precision approach operations include those based on conventional navigation aids with “or GPS” in the title and those with “GPS” and “RNAV(GPS)” in the title to “LNAV” minimums.
<The following statement applies to all types of GNSS stand-alone equipment>:
Navigation information is referenced to the WGS-84 reference system, and should only be used where the Aeronautical Information Publication (including electronic data and aeronautical charts) conform to WGS-84 or equivalent.
<For TSO-C129(AR), TSO-C145/C146(AR), and TSO-C196(AR) equipment that complies with the requirements in appendix 1 of this AC:> The ABC equipment as installed has been found to comply with the requirements for GPS oceanic/remote navigation, when used in conjunction with the ABC prediction program. This does not constitute an operational approval.
FAA Approved Page <> of <> Date: ________ A5-5
Appendix 5
Sample Airplane/Rotorcraft Flight Manual (Continued)
Installation Center/Repair Station Model XXX GPS 123 Fourth Street Navigation System Anytown, USA
SECTION 2 - LIMITATIONS
1. The ABC Model XXX GPS Quick Reference Guide, P/N <insert part number>, dated <insert date> (or later appropriate revision) must be immediately available to the flight crew whenever navigation is predicated on the use of the system.
2. The system must use at least software version <insert version identification> as the minimum version.
3. A valid and compatible database must be installed and contain current data.
<Limitation for TSO-C129(AR) and TSO-C196(AR) equipment:>
4. The aircraft must have other operational, approved navigation equipment installed appropriate to the operation.
<Limitation for all GNSS equipment:>
5. The TSO-C<insert number and revision> equipment has an alternate airport flight planning limitation. Refer to section 1-1-19 in the Airman’s Information Manual.
6. <Specify any additional limitations applicable to the particular installation.>
SECTION 3 - EMERGENCY/ABNORMAL PROCEDURES
EMERGENCY PROCEDURES No Change
ABNORMAL PROCEDURES
1. If ABC Model XXX GPS navigation information is not available or invalid, use remaining operational navigation equipment as appropriate.
2. If loss of integrity monitoring message is displayed, revert to an alternate means of navigation appropriate to the route and phase of flight or periodically cross-check the GPS guidance to other, approved means of navigation.
SECTION 4 - NORMAL PROCEDURES
1. Normal operating procedures are outlined in the ABC Model XXX GPS Pilot's Guide.
FAA Approved Page <> of <> Date: ________ A5-6
Appendix 5
A5-7 Sample Airplane/Rotorcraft Flight Manual (Continued)
Installation Center/Repair Station Model XXX GPS 123 Fourth Street Navigation System Anytown, USA
2. <Describe approach mode sequencing.>
3. System Annunciators <applicable to installations with external annunciators>
a. Waypoint - <describe each annunciator>
b. Message - <describe each annunciator>
c. Approach - <describe each annunciator>
d. <describe any other annunciators>
4. System Switches <applicable to installations with external switches>
a. Nav/GPS - <describe switch use and function>
b. RMI Switch - <describe switch use and function>
c. <describe any other switches>
5. Pilot's Display <describe the pilot's GPS display(s)>
6. Flight Director/Autopilot Coupled Operation <describe the procedures for coupling GPS to the flight director and/or autopilot system(s)>
7. <include any other normal operating procedures necessary>
SECTION 5 - PERFORMANCE No Change
SECTION 6 - WEIGHT AND BALANCE <Refer to revised weight and balance data, if applicable.>
SECTION 7 - SYSTEM DESCRIPTION <Provide a brief description of the system, its operation, installation, etc.>
FAA Approved Page <> of <> Date: ________
Appendix 6
Appendix 6. Installation of GNSS Equipment for VFR Use Only.
A6-1. Introduction.
This appendix provides guidelines for the installation of stand-alone GNSS systems used for VFR navigation only.
A6-2. General.
GNSS equipment may be installed on a no-hazard basis as a supplement to VFR navigation.
Such installations need only to verify that the GNSS installation does not introduce a hazard to the aircraft (e.g., properly secured for crashworthiness, not combustible, etc) including EMI/EMC. Loss of or misleading VFR navigation information is considered a minor hazard failure condition; therefore, it is acceptable to have development assurance level D for software per RTCA/DO-178B, and electronic hardware, per RTCA/DO-254. A readable placard must be installed in clear view of the pilot stating that the equipment is only to be used for VFR operations, unless the equipment automatically displays this message on start-up and pilot action is required to clear the message. An AFMS/RFMS is not required since the placard or display contains the equipment limitation.
A6-3. Applicability.
This appendix applies to all un-pressurized aircraft less than 6000 pounds where the modification is classified as a minor alteration.
A6-4. Technical Instructions.
Install the GPS as follows:
a. The GPS equipment should be located in a position which is viewable and accessible to the pilot from his/her normally seated position. The installed GPS equipment should not:
(1) Restrict access to or view of any control, display or indicator;
(2) Restrict movement of the flight controls;
(3) Interfere with the pilot’s vision along the flight path; or
(4) Restrict pilot/passenger egress.
b. The installation should be carried out in accordance with the equipment manufacturer’s installation manual/instructions, the aircraft maintenance manual and the guidelines in AC 43.13-2 (latest revision). The installation should conform to the following requirements:
(1) Equipment manufacturer-supplied or standard parts should be used.
A6-1
Appendix 6
(2) If a ‘non-standard’ method of installation is used, the equipment manufacturer’s recommended procedures should be followed.
(3) The GPS mounting should be tested to ensure that it will be restrained throughout the flight envelope.
(4) Where a modification is required to the aircraft structure to show compliance with paragraph A6-4.b(3) of this appendix, the modification is to be carried out in accordance with the aircraft maintenance manual and the guidelines in the latest revisions of AC 43.13-1 and AC 43.14-2.
c. If required, install a remote GPS antenna as follows:
(1) Determine a suitable location for the GPS antenna on the upper fuselage.
Particular care should be taken to ensure that at least the minimum separation is maintained between the GPS antenna and VHF communications and ELT antennas.
(2) Install the equipment manufacturer-approved GPS antenna in accordance with the equipment manufacturer’s installation manual/instructions, the aircraft maintenance manual and the guidelines in AC 43.13-2 (latest revision). The GPS antenna installation should be tested to ensure that it would be restrained throughout the flight envelope.
(3) If using an internally mounted, equipment manufacturer-supplied remote antenna, install the antenna in accordance with the equipment manufacturer’s installation manual/instructions. Ensure that the antenna and associated cable will not interfere with pilot’s vision, aircraft controls or displays, or pilot/passenger egress.
d. Install and placard an appropriately rated circuit breaker or fuse.
e. If required, install a remote GPS indicator as follows:
(1) Determine a suitable location for the GPS indicator. The indicator should be located in the instrument panel and readily viewable to the pilot from his/her normally seated position.
(2) Install the indicator in accordance with the equipment manufacturer’s installation manual/instructions, the aircraft maintenance manual and the guidelines in AC
43.13-2 (latest revision).
(3) Interconnect the GPS, power supply, indicator and antenna (as required) in accordance with the equipment manufacturer’s installation manual/instructions.
f. Unless the equipment automatically displays a message on start-up and pilot action is required to clear the message, install the following placard in the vicinity of the GPS and in clear view of the pilot: GPS APPROVED FOR VFR USE ONLY.
A6-2