AC 20-199 Appendix D D.7 Installation Manual (IM).
A document developed and made available by the equipment manufacturer of a system, subsystem, or component that specifies the performance characteristics, interface specifications, installation constraints and limitations, installation requirements, calibration (if applicable), on-aircraft testing, maintenance, troubleshooting procedures, and any necessary requirements for other integrated equipment.
D.8 Interference Tolerance Mask (ITM).
The specification that defines the maximum amount of RFI at the surface of the RA antenna(s) that the RA system can safely tolerate.
D.9 Irregular Approach Terrain.
Includes cliffs, valleys, sea-walls, hilltops, and sloping runways, in the area of final approach, within a pproximately 1500 ft of the landing threshold.
D.10 Loop Loss.
The round-trip attenuation of the RF signal received by the radio altimeter system consisting of a delayed, attenuated, and possibly dispersed or modulated version of the transmitter output waveform due to propagation of this signal through space and interaction of the signal with one or more radar targets (i.e., sources of radar reflectivity).
D.11 Multiplex Installation.
An installation of more than one RA system of the same type onboard a single aircraft.
Typically, this will consist of either dual or triplex installation.
D.12 Out-of-Band Radio Frequency Interference (RFI).
External RFI signals outside the RA operating frequency band (i.e., at frequencies less than 4.2 GHz or greater than 4.4 GHz).
D.13 Radio Altimeter Antenna.
The subsystem or component of the RA system that takes a conducted RF signal provided by the transceiver and radiates it toward the terrain and receives a radiated RF signal reflected from the terrain and provides a conducted RF signal to the transceiver.
An RA system will include one or multiple RA antennas.
D.14 Radio Altimeter Indicator or Display.
The subsystem or component of the RA system provides a visual indication of the measured altitude result determined by the RA transceiver. An RA system may include D-2
AC 20-199 Appendix D one, multiple, or no RA indicators or displays. It may be a standalone indicator or display component for the sole purpose of displaying RA system outputs, or it may be a function incorporated into an MFD system, such as an EFIS.
D.15 Radio Altimeter System.
A complete system consisting of receiver and transmitter, one or more antennas, RF cables (if the antenna(s) are not integrated into the same LRU as the receiver and transmitter), and input/output interfaces (which may include a display of altitude information as a visual output interface, either integrated or as a part of a separate display or indicator component).
D.16 Radio Altimeter Transceiver.
The subsystem or component of the RA system that generates and transmits the RF signal and receives, processes, and determines a measured altitude result from the RF signal reflected from the terrain. An RA will include one and only one RA transceiver.
D.17 RF Filter Subassembly (RFFSA).
A subassembly implemented within the RA transceiver LRU that selectively filters RF signals outside of the RA band. The RA transceiver could be implemented with an RFFSA at the transmitter output port, the receiver input port, or both.
D.18 Transceiver Subassembly.
A subassembly implemented within the RA transceiver LRU that performs all of the normal functions of the RA, with the exception of the selective filtering implemented in one or more RFFSAs.
D.19 Terrain Smoothness.
Ranging from smooth to rough (where rough terrains may be further characterized by the feature size and density of the surface roughness).
D.20 Terrain Flatness.
Ranging from flat to undulating (where undulating terrains may be further characterized by the depth and period of their undulations).
D.21 Terrain Inclination.
Ranging from level to sloped (where sloped terrains may be further characterized by the angle of the terrain slope).
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AC 20-199 Appendix D D.22 Terrain Surface Features.
Ranging from bare to densely featured. Terrains may be further characterized by the density of the surface features (e.g., sparsely or densely featured, as well as the size of the surface features).
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AC 20-199 Appendix E APPENDIX E. ACRONYMS Acronym Definition AC Advisory Circular ACAS Airborne Collision Avoidance System AFGCS Automatic Flight Guidance and Control System AFM Aircraft Flight Manual AMC Acceptable Means of Compliance ARP Aerospace Recommended Practice AWGN Additive White Gaussian Noise CS Certification Specification CW Continuous Waveform DH Decision Height EASA European Union Aviation Safety Agency EFIS Electronic Flight Instrument System EFVS Enhanced Flight Vision Systems EUROCAE European Organization for Civil Aviation Equipment FAA Federal Aviation Administration HAGL Height Above Ground Level HIRF High-Intensity Radiated Fields HTAWS Helicopter Terrain Awareness and Warning System ICAO International Civil Aviation Organization IM Installation Manual ITM Interference Tolerance Mask LRU Line Replaceable Unit MASPS Minimum Aviation System Performance Standards MFD Multifunction Display MOC Method of Compliance MOPS Minimum Operational Performance Standards NVG Night Vision Goggle PAPR Peak-to-Average Power Ratio PFD Power Flux-Density RA Radio Altimeter RF Radio Frequency RFFSA RF Filter Subassembly RFI Radio Frequency Interference RTCA Radio Technical Commission for Aeronautics RX Reverse Port SAE Society of Automotive Engineers SSA System Safety Assessment STC Supplemental Type Certificate TAWS Terrain Awareness and Warning System TC Type Certificate TCAS Traffic Alert and Collision Avoidance System E-1
AC 20-199 Appendix E Acronym Definition TSO Technical Standard Order TSOA Technical Standard Order Authorization UUT Unit Under Test E-2
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