 AIM 4/3/14 1−1−33 Navigation Aids locations close to the edge of the coverage may have a lower availability of vertical guidance. c. General Requirements 1. WAAS avionics must be certified in accordance with Technical Standard Order (TSO) TSO−C145a, Airborne Navigation Sensors Using the (GPS) Augmented by the Wide Area Augmentation System (WAAS); or TSO−C146a, Stand−Alone Airborne Navigation Equipment Using the Global Positioning System (GPS) Augmented by the Wide Area Augmentation System (WAAS), and installed in accordance with Advisory Circular (AC) 20−130A, Airworthiness Approval of Navigation or Flight Management Systems Integrating Multiple Naviga- tion Sensors, or AC 20−138A, Airworthiness Approval of Global Positioning System (GPS) Navigation Equipment for Use as a VFR and IFR Navigation System. 2. GPS/WAAS operation must be conducted in accordance with the FAA−approved aircraft flight manual (AFM) and flight manual supplements. Flight manual supplements will state the level of approach procedure that the receiver supports. IFR approved WAAS receivers support all GPS only operations as long as lateral capability at the appropriate level is functional. WAAS monitors both GPS and WAAS satellites and provides integrity. 3. GPS/WAAS equipment is inherently capable of supporting oceanic and remote operations if the operator obtains a fault detection and exclusion (FDE) prediction program. 4. Air carrier and commercial operators must meet the appropriate provisions of their approved operations specifications. 5. Prior to GPS/WAAS IFR operation, the pilot must review appropriate Notices to Airmen (NOT- AMs) and aeronautical information. This information is available on request from a Flight Service Station. The FAA will provide NOTAMs to advise pilots of the status of the WAAS and level of service available. (a) The term UNRELIABLE is used in conjunction with GPS and WAAS NOTAMs. The term UNRELIABLE is an advisory to pilots indicating the expected level of WAAS service (LNAV/VNAV, LPV) may not be available; e.g., !BOS BOS WAAS LPV AND LNAV/VNAV MNM UNREL WEF 0305231700 − 0305231815. WAAS UNRELIABLE NOTAMs are predictive in nature and published for flight planning purposes. Upon commencing an approach at locations NOTAMed WAAS UNRELIABLE, if the WAAS avionics indicate LNAV/VNAV or LPV service is available, then vertical guidance may be used to complete the approach using the displayed level of service. Should an outage occur during the approach, reversion to LNAV minima may be required. (1) Area−wide WAAS UNAVAILABLE NOTAMs indicate loss or malfunction of the WAAS system. In flight, Air Traffic Control will advise pilots requesting a GPS or RNAV (GPS) approach of WAAS UNAVAILABLE NOTAMs if not contained in the ATIS broadcast. (2) Site−specific WAAS UNRELIABLE NOTAMs indicate an expected level of service, e.g., LNAV/VNAV or LPV may not be available. Pilots must request site−specific WAAS NOTAMs during flight planning. In flight, Air Traffic Control will not advise pilots of WAAS UNRELIABLE NOTAMs. (3) When the approach chart is annotated with the symbol, site−specific WAAS UNRELI- provided for outages in WAAS LNAV/VNAV and LPV vertical service. Vertical outages may occur daily at these locations due to being close to the edge of WAAS system coverage. Use LNAV or circling minima for flight planning at these locations, whether as a destination or alternate. For flight operations at these locations, when the WAAS avionics indicate that LNAV/VNAV or LPV service is available, then the vertical guidance may be used to complete the approach using the displayed level of service. Should an outage occur during the procedure, reversion to LNAV minima may be required. NOTE − Area −wide WAAS UNAVAILABLE NOTAMs apply to all airports in the WAAS UNAVAILABLE area designated inthe NOTAM, including approaches at airports where an approach chart is annotated with the symbol. 6. GPS/WAAS was developed to be used within SBAS GEO coverage (WAAS or other interoperable system) without the need for other radio navigation equipment appropriate to the route of flight to be flown. Outside the SBAS coverage or in the event of a WAAS failure, GPS/WAAS equipment reverts to Page 2
AIM 4/3/14 1−1−34 Navigation Aids GPS−only operation and satisfies the requirements for basic GPS equipment. 7. Unlike TSO−C129 avionics, which were certified as a supplement to other means of navigation, WAAS avionics are evaluated without reliance on other navigation systems. As such, installation of WAAS avionics does not require the aircraft to have other equipment appropriate to the route to be flown. (a) Pilots with WAAS receivers may flight plan to use any instrument approach procedure authorized for use with their WAAS avionics as the planned approach at a required alternate, with the following restrictions. When using WAAS at an alternate airport, flight planning must be based on flying the RNAV (GPS) LNAV or circling minima line, or minima on a GPS approach procedure, or conventional approach procedure with “or GPS” in the title. Code of Federal Regulation (CFR) Part 91 nonprecision weather requirements must be used for planning. Upon arrival at an alternate, when the WAAS navigation system indicates that LNAV/ VNAV or LPV service is available, then vertical guidance may be used to complete the approach using the displayed level of service. The FAA has begun NA (Alternate Minimums Not Authorized) symbol from select RNAV (GPS) and GPS approach procedures so they may be used by approach approved WAAS receivers at alternate airports. Some approach procedures will still require NA for other reasons, such as no weather reporting, so it cannot be removed from all procedures. Since every procedure must be individu- NA from RNAV (GPS) and GPS procedures will take some time. NOTE − Properly trained and approved, as required, TSO-C145()and TSO-C146() equipped users (WAAS users) with andusing approved baro-VNAV equipment may plan forLNAV/VNAV DA at an alternate airport. Specificallyauthorized WAAS users with and using approvedbaro-VNAV equipment may also plan for RNP 0.3 DA at thealternate airport as long as the pilot has verified RNP availability through an approved prediction program. d. Flying Procedures with WAAS 1. WAAS receivers support all basic GPS approach functions and provide additional capabilit- ies. One of the major improvements is the ability to generate glide path guidance, independent of ground equipment or barometric aiding. This eliminates several problems such as hot and cold temperature effects, incorrect altimeter setting or lack of a local altimeter source. It also allows approach procedures to be built without the cost of installing ground stations at each airport or runway. Some approach certified receivers may only generate a glide path with performance similar to Baro−VNAV and are only approved to fly the LNAV/VNAV line of minima on the RNAV (GPS) approach charts. Receivers with additional capability (including faster update rates and smaller integrity limits) are approved to fly the LPV line of minima. The lateral integrity changes dramatically from the 0.3 NM (556 meter) limit for GPS, LNAV and LNAV/VNAV approach mode, to 40 meters for LPV. It also provides vertical integrity monitoring, which bounds the vertical error to 50 meters for LNAV/VNAV and LPVs with minima of 250’ or above, and bounds the vertical error to 35 meters for LPVs with minima below 250’. 2. When an approach procedure is selected and active, the receiver will notify the pilot of the most accurate level of service supported by the combina- tion of the WAAS signal, the receiver, and the selected approach, using the naming conventions on the minima lines of the selected approach procedure. For example, if an approach is published with LPV minima and the receiver is only certified for LNAV/VNAV, the equipment would indicate “LNAV/VNAV available,” even though the WAAS signal would support LPV. If flying an existing LNAV/VNAV procedure with no LPV minima, the receiver will notify the pilot “LNAV/VNAV available,” even if the receiver is certified for LPV and the signal supports LPV. If the signal does not support vertical guidance on procedures with LPV and/or LNAV/VNAV minima, the receiver annunci- ation will read “LNAV available.” On lateral only procedures with LP and LNAV minima the receiver will indicate “LP available” or “LNAV available” based on the level of lateral service available. Once the level of service notification has been given, the receiver will operate in this mode for the duration of the approach procedure, unless that level of service becomes unavailable. The receiver cannot change back to a more accurate level of service until the next time an approach is activated. NOTE − Receivers do not “fail down” to lower levels of service Page 3
AIM 4/3/14 1−1−35 Navigation Aids vertical off flag appears, the pilot may elect to use theLNAV minima if the rules under which the flight isoperating allow changing the type of approach being flownafter commencing the procedure. If the lateral integritylimit is exceeded on an LP approach, a missed approachwill be necessary since there is no way to reset the lateral alarm limit while the approach is active. 3. Another additional feature of WAAS receiv- ers is the ability to exclude a bad GPS signal and continue operating normally. This is normally accomplished by the WAAS correction information. Outside WAAS coverage or when WAAS is not available, it is accomplished through a receiver algorithm called FDE. In most cases this operation will be invisible to the pilot since the receiver will continue to operate with other available satellites after excluding the “bad” signal. This capability increases the reliability of navigation. 4. Both lateral and vertical scaling for the LNAV/VNAV and LPV approach procedures are different than the linear scaling of basic GPS. When the complete published procedure is flown, +/−1 NM linear scaling is provided until two (2) NM prior to the FAF, where the sensitivity increases to be similar to the angular scaling of an ILS. There are two differ- ences in the WAAS scaling and ILS: 1) on long final approach segments, the initial scaling will be +/−0.3 NM to achieve equivalent performance to GPS (and better than ILS, which is less sensitive far from the runway); 2) close to the runway threshold, the scaling changes to linear instead of continuing to become more sensitive. The width of the final approach course is tailored so that the total width is usually 700 feet at the runway threshold. Since the origin point of the lateral splay for the angular portion of the final is not fixed due to antenna placement like localizer, the splay angle can remain fixed, making a consistent width of final for aircraft being vectored onto the final approach course on different length runways. When the complete published procedure is not flown, and instead the aircraft needs to capture the extended final approach course similar to ILS, the vector to final (VTF) mode is used. Under VTF the scaling is linear at +/−1 NM until the point where the ILS angular splay reaches a width of +/−1 NM regardless of the distance from the FAWP. 5. The WAAS scaling is also different than GPS TSO−C129 in the initial portion of the missed approach. Two differences occur here. First, the scaling abruptly changes from the approach scaling to the missed approach scaling, at approximately the departure end of the runway or when the pilot requests missed approach guidance rather than ramping as GPS does. Second, when the first leg of the missed approach is a Track to Fix (TF) leg aligned within 3 degrees of the inbound course, the receiver will change to 0.3 NM linear sensitivity until the turn initiation point for the first waypoint in the missed approach procedure, at which time it will abruptly change to terminal (+/−1 NM) sensitivity. This allows the elimination of close in obstacles in the early part of the missed approach that may cause the DA to be raised. 6. A new method has been added for selecting the final approach segment of an instrument approach. Along with the current method used by most receivers using menus where the pilot selects the airport, the runway, the specific approach procedure and finally the IAF, there is also a channel number selection method. The pilot enters a unique 5−digit number provided on the approach chart, and the receiver recalls the matching final approach segment from the aircraft database. A list of information including the available IAFs is displayed and the pilot selects the appropriate IAF. The pilot should confirm that the correct final approach segment was loaded by cross checking the Approach ID, which is also provided on the approach chart. 7. The Along−Track Distance (ATD) during the final approach segment of an LNAV procedure (with a minimum descent altitude) will be to the MAWP. On LNAV/VNAV and LPV approaches to a decision altitude, there is no missed approach waypoint so the along−track distance is displayed to a point normally located at the runway threshold. In most cases the MAWP for the LNAV approach is located on the runway threshold at the centerline, so these distances will be the same. This distance will always vary slightly from any ILS DME that may be present, since the ILS DME is located further down the runway. Initiation of the missed approach on the LNAV/ VNAV and LPV approaches is still based on reaching the decision altitude without any of the items listed in 14 CFR Section 91.175 being visible, and must not be delayed until the ATD reaches zero. The WAAS receiver, unlike a GPS receiver, will automatically sequence past the MAWP if the missed approach procedure has been designed for RNAV. The pilot Page 4
AIM 4/3/14 1−1−36 Navigation Aids may also select missed approach prior to the MAWP, however, navigation will continue to the MAWP prior to waypoint sequencing taking place. 1 − 1 − 20. Ground Based Augmentation System (GBAS) Landing System (GLS) a. General 1. The GLS provides precision navigation guidance for exact alignment and descent of aircraft on approach to a runway. It provides differential augmentation to the Global Navigation Satellite System (GNSS). NOTE − GBAS is the ICAO term for Local Area Augmentation 2. LAAS was developed as an “ILS look−alike” system from the pilot perspective. LAAS is based on GPS signals augmented by ground equipment and has been developed to provide GLS precision approaches similar to ILS at airfields. 3. GLS provides guidance similar to ILS approaches for the final approach segment; portions of the GLS approach prior to and after the final approach segment will be based on Area Navigation (RNAV) or Required Navigation Performance (RNP). 4. The equipment consists of a GBAS Ground Facility (GGF), four reference stations, a VHF Data Broadcast (VDB) uplink antenna, and an aircraft GBAS receiver. b. Procedure 1. Pilots will select the five digit GBAS channel number of the associated approach within the Flight Management System (FMS) menu or manually select the five digits (system dependent). Selection of the GBAS channel number also tunes the VDB. 2. Following procedure selection, confirmation that the correct LAAS procedure is loaded can be accomplished by cross checking the charted Reference Path Indicator (RPI) or approach ID with the cockpit displayed RPI or audio identification of the RPI with Morse Code (for some systems). 3. The pilot will fly the GLS approach using the same techniques as an ILS, once selected and identified. 1 − 1 − 21. Precision Approach Systems other than ILS, GLS, and MLS a. General Approval and use of precision approach systems other than ILS, GLS and MLS require the issuance of special instrument approach procedures. b. Special Instrument Approach Procedure 1. Special instrument approach procedures must be issued to the aircraft operator if pilot training, aircraft equipment, and/or aircraft performance is different than published procedures. Special instru- ment approach procedures are not distributed for general public use. These procedures are issued to an aircraft operator when the conditions for operations approval are satisfied. 2. General aviation operators requesting ap- proval for special procedures should contact the local Flight Standards District Office to obtain a letter of authorization. Air carrier operators requesting approval for use of special procedures should contact their Certificate Holding District Office for authoriz- ation through their Operations Specification. c. Transponder Landing System (TLS) 1. The TLS is designed to provide approach guidance utilizing existing airborne ILS localizer, glide slope, and transponder equipment. 2. Ground equipment consists of a transponder interrogator, sensor arrays to detect lateral and vertical position, and ILS frequency transmitters. The TLS detects the aircraft’s position by interrogating its transponder. It then broadcasts ILS frequency signals to guide the aircraft along the desired approach path. 3. TLS instrument approach procedures are designated Special Instrument Approach Procedures. Special aircrew training is required. TLS ground equipment provides approach guidance for only one aircraft at a time. Even though the TLS signal is received using the ILS receiver, no fixed course or glidepath is generated. The concept of operation is very similar to an air traffic controller providing radar vectors, and just as with radar vectors, the guidance is valid only for the intended aircraft. The TLS ground equipment tracks one aircraft, based on its transponder code, and provides correction signals to course and glidepath based on the position of the tracked aircraft. Flying the TLS corrections com- puted for another aircraft will not provide guidance Page 5
AIM 4/3/14 1−1−37 Navigation Aids relative to the approach; therefore, aircrews must not use the TLS signal for navigation unless they have received approach clearance and completed the required coordination with the TLS ground equip- ment operator. Navigation fixes based on conventional NAVAIDs or GPS are provided in the special instrument approach procedure to allow aircrews to verify the TLS guidance. d. Special Category I Differential GPS (SCAT − I DGPS) 1. The SCAT−I DGPS is designed to provide approach guidance by broadcasting differential correction to GPS. 2. SCAT−I DGPS procedures require aircraft equipment and pilot training. 3. Ground equipment consists of GPS receivers and a VHF digital radio transmitter. The SCAT−I DGPS detects the position of GPS satellites relative to GPS receiver equipment and broadcasts differen- tial corrections over the VHF digital radio. 4. Category I Ground Based Augmentation System (GBAS) will displace SCAT−I DGPS as the public use service. REFERENCE − AIM, Para 5 −4−7f, Instrument Approach Procedures. Page 6
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AIM 4/3/14 1−2−1 Area Navigation (RNAV) and Required Navigation Performance (RNP) Section 2. Area Navigation (RNAV) and Required Navigation Performance (RNP) 1 − 2 − 1. Area Navigation (RNAV) a. General. RNAV is a method of navigation that permits aircraft operation on any desired flight path within the coverage of ground or space based navigation aids or within the limits of the capability of self−contained aids, or a combination of these. In the future, there will be an increased dependence on the use of RNAV in lieu of routes defined by ground−based navigation aids. RNAV routes and terminal procedures, including departure procedures (DPs) and standard terminal arrivals (STARs), are designed with RNAV systems in mind. There are several potential advantages of RNAV routes and procedures: 1. Time and fuel savings, 2. Reduced dependence on radar vectoring, altitude, and speed assignments allowing a reduction in required ATC radio transmissions, and 3. More efficient use of airspace. In addition to information found in this manual, guidance for domestic RNAV DPs, STARs, and routes may also be found in Advisory Circu- lar 90−100A, U.S. Terminal and En Route Area Navigation (RNAV) Operations. b. RNAV Operations. RNAV procedures, such as DPs and STARs, demand strict pilot awareness and maintenance of the procedure centerline. Pilots should possess a working knowledge of their aircraft navigation system to ensure RNAV procedures are flown in an appropriate manner. In addition, pilots should have an understanding of the various waypoint and leg types used in RNAV procedures; these are discussed in more detail below. 1. Waypoints. A waypoint is a predetermined geographical position that is defined in terms of latitude/longitude coordinates. Waypoints may be a simple named point in space or associated with existing navaids, intersections, or fixes. A waypoint is most often used to indicate a change in direction, speed, or altitude along the desired path. RNAV procedures make use of both fly−over and fly−by waypoints. (a) Fly −by waypoints. Fly−by waypoints are used when an aircraft should begin a turn to the next course prior to reaching the waypoint separating the two route segments. This is known as turn anticipation. (b) Fly −over waypoints. Fly−over way- points are used when the aircraft must fly over the point prior to starting a turn. NOTE − FIG 1 −2−1 illustrates several differences between a fly−by and a fly −over waypoint. FIG 1 −2−1 Fly −by and Fly−over Waypoints 2. RNAV Leg Types. A leg type describes the desired path proceeding, following, or between waypoints on an RNAV procedure. Leg types are identified by a two−letter code that describes the path (e.g., heading, course, track, etc.) and the termination point (e.g., the path terminates at an altitude, distance, fix, etc.). Leg types used for procedure design are included in the aircraft navigation database, but not normally provided on the procedure chart. The narrative depiction of the RNAV chart describes how a procedure is flown. The “path and terminator concept” defines that every leg of a procedure has a termination point and some kind of path into that termination point. Some of the available leg types are described below. Page 8
AIM 4/3/14 1−2−2 Area Navigation (RNAV) and Required Navigation Performance (RNP) (a) Track to Fix. A Track to Fix (TF) leg is intercepted and acquired as the flight track to the following waypoint. Track to a Fix legs are sometimes called point−to−point legs for this reason. See FIG 1−2−2. (b) Direct to Fix. A Direct to Fix (DF) leg is a path described by an aircraft’s track from an initial area direct to the next waypoint. Narrative: “left See FIG 1−2−3. FIG 1 −2−2 Track to Fix Leg Type FIG 1 −2−3 Direct to Fix Leg Type Page 9
AIM 4/3/14 1−2−3 Area Navigation (RNAV) and Required Navigation Performance (RNP) (c) Course to Fix. A Course to Fix (CF) leg is a path that terminates at a fix with a specified course at that fix. Narrative: “on course 078 to PRIMY See FIG 1−2−4. FIG 1 −2−4 Course to Fix Leg Type (d) Radius to Fix. A Radius to Fix (RF) leg is defined as a constant radius circular path around a defined turn center that terminates at a fix. See FIG 1−2−5. FIG 1 −2−5 Radius to Fix Leg Type (e) Heading. A Heading leg may be defined as, but not limited to, a Heading to Altitude (VA), Heading to DME range (VD), and Heading to Manual Termination, i.e., Vector (VM). Narrative: “climb of PXR VORTAC, right turn heading 360”, “fly 3. Navigation Issues. Pilots should be aware of their navigation system inputs, alerts, and annunciations in order to make better−informed decisions. In addition, the availability and suitability of particular sensors/systems should be considered. (a) GPS. Operators using TSO−C129 sys- tems should ensure departure and arrival airports are entered to ensure proper RAIM availability and CDI sensitivity. (b) DME/DME. Operators should be aware that DME/DME position updating is dependent on FMS logic and DME facility proximity, availability, geometry, and signal masking. (c) VOR/DME. Unique VOR characteris- tics may result in less accurate values from VOR/DME position updating than from GPS or DME/DME position updating. (d) Inertial Navigation. Inertial reference units and inertial navigation systems are often coupled with other types of navigation inputs, e.g., DME/DME or GPS, to improve overall navigation system performance. NOTE − Specific inertial position updating requirements may 4. Flight Management System (FMS). An FMS is an integrated suite of sensors, receivers, and computers, coupled with a navigation database. These systems generally provide performance and RNAV guidance to displays and automatic flight control systems. GPS, DME, VOR, LOC and IRU. These inputs may be applied to a navigation solution one at a time or in combination. Some FMSs provide for the detection and isolation of faulty navigation information. FMSs will normally rely on GPS and/or DME/DME (that is, the use of distance information from two or more DME stations) for position updates. Other inputs may also be incorporated based on FMS system architecture and navigation source geometry. NOTE − DME/DME inputs coupled with one or more IRU(s) are Page 10
AIM 4/3/14 1−2−4 Area Navigation (RNAV) and Required Navigation Performance (RNP) 1 − 2 − 2. Required Navigation Performance (RNP) a. General. RNP is RNAV with on−board navigation monitoring and alerting, RNP is also a statement of navigation performance necessary for operation within a defined airspace. A critical component of RNP is the ability of the aircraftnavigation system to monitor its achieved navigationperformance, and to identify for the pilot whether theoperational requirement is, or is not being met during an operation . This on−board performance monitor- ing and alerting capability therefore allows a lessened reliance on air traffic control intervention (via radar monitoring, automatic dependent surveillance (ADS), multilateration, communications), and/or route separation to achieve the overall safety of the operation. RNP capability of the aircraft is a major component in determining the separation criteria to ensure that the overall containment of the operation is met. upon the aircraft equipment and the navigation infrastructure. For example, an aircraft may be equipped and certified for RNP 1.0, but may not be capable of RNP 1.0 operations due to limited navaid coverage. b. RNP Operations. 1. RNP Levels. An RNP “level” or “type” is applicable to a selected airspace, route, or procedure. As defined in the Pilot/Controller Glossary, the RNP Level or Type is a value typically expressed as a distance in nautical miles from the intended centerline of a procedure, route, or path. RNP applications also account for potential errors at some multiple of RNP level (e.g., twice the RNP level). (a) Standard RNP Levels. U.S. standard values supporting typical RNP airspace are as specified in TBL 1−2−1 below. Other RNP levels as identified by ICAO, other states and the FAA may also be used. (b) Application of Standard RNP Levels. U.S. standard levels of RNP typically used for various routes and procedures supporting RNAV operations may be based on use of a specific navigational system or sensor such as GPS, or on multi−sensor RNAV systems having suitable perfor- mance. (c) Depiction of Standard RNP Levels. The applicable RNP level will be depicted on affected charts and procedures. TBL 1 −2−1 U.S. Standard RNP Levels RNP Level Typical Application Primary Route Width (NM) − Centerline to Boundary 0.1 to 1.0 RNP AR Approach Segments 0.1 to 1.0 0.3 to 1.0 RNP Approach Segments 0.3 to 1.0 1 Terminal and En Route 1.0 2 En Route 2.0 NOTE − 1. The “performance” of navigation in RNP refers not only to the level of accuracy of a particular sensor or aircraftnavigation system, but also to the degree of precision with which the aircraft will be flown. 2. Specific required flight procedures may vary for different RNP levels. Page 11
AIM 4/3/14 1−2−5 Area Navigation (RNAV) and Required Navigation Performance (RNP) TBL 1 −2−2 RNP Levels Supported for International Operations RNP Level Typical Application 4 Projected for oceanic/remote areas where 30 NM horizontal separation is applied 10 Oceanic/remote areas where 50 NM lateral separation is applied c. Other RNP Applications Outside the U.S. The FAA and ICAO member states have led initiatives in implementing the RNP concept to oceanic operations. For example, RNP−10 routes have been established in the northern Pacific (NOPAC) which has increased capacity and efficiency by reducing the distance between tracks to 50 NM. (See TBL 1−2−2.) d. Aircraft and Airborne Equipment Eligibility for RNP Operations. Aircraft meeting RNP criteria will have an appropriate entry including special conditions and limitations in its Aircraft Flight Manual (AFM), or supplement. Operators of aircraft not having specific AFM−RNP certification may be issued operational approval including special condi- tions and limitations for specific RNP levels. NOTE − Some airborne systems use Estimated Position Uncer-tainty (EPU) as a measure of the current estimatednavigational performance. EPU may also be referred to asActual Navigation Performance (ANP) or Estimated Position Error (EPE). 1 − 2 − 3. Use of Suitable Area Navigation (RNAV) Systems on Conventional a. Discussion. This paragraph sets forth policy, while providing operational and airworthiness guidance regarding the suitability and use of RNAV systems when operating on, or transitioning to, conventional, non−RNAV routes and procedures within the U.S. National Airspace System (NAS): 1. Use of a suitable RNAV system as a Substitute Means of Navigation when a Very−High Frequency (VHF) Omni−directional Range (VOR), Distance Measuring Equipment (DME), Tactical Air Navigation (TACAN), VOR/TACAN (VORTAC), VOR/DME, Non−directional Beacon (NDB), or compass locator facility including locator outer marker and locator middle marker is out−of−service (that is, the navigation aid (NAVAID) information is not available); an aircraft is not equipped with an Automatic Direction Finder (ADF) or DME; or the installed ADF or DME on an aircraft is not operational. For example, if equipped with a suitable RNAV system, a pilot may hold over an out−of− service NDB. 2. Use of a suitable RNAV system as an Alternate Means of Navigation when a VOR, DME, VORTAC, VOR/DME, TACAN, NDB, or compass locator facility including locator outer marker and locator middle marker is operational and the respective aircraft is equipped with operational navigation equipment that is compatible with conventional navaids. For example, if equipped with a suitable RNAV system, a pilot may fly a procedure or route based on operational VOR using that RNAV system without monitoring the VOR. NOTE − 1. Additional information and associated requirementsare available in Advisory Circular 90-108 titled “Use ofSuitable RNAV Systems on Conventional Routes and Procedures.” 2. Good planning and knowledge of your RNAV system are 3. Pilots planning to use their RNAV system as a substitute −of−service NAVAID may need to advise ATC of this intent and capability. 4. The navigation database should be current for theduration of the flight. If the AIRAC cycle will changeduring flight, operators and pilots should establishprocedures to ensure the accuracy of navigation data,including suitability of navigation facilities used to definethe routes and procedures for flight. To facilitate validatingdatabase currency, the FAA has developed procedures forpublishing the amendment date that instrument approachprocedures were last revised. The amendment date followsthe amendment number, e.g., Amdt 4 14Jan10. Currency ofgraphic departure procedures and STARs may beascertained by the numerical designation in the proceduretitle. If an amended chart is published for the procedure, or the procedure amendment date shown on the chart is on or Page 12
AIM 4/3/14 1−2−6 Area Navigation (RNAV) and Required Navigation Performance (RNP) after the expiration date of the database, the operator must b. Types of RNAV Systems that Qualify as a Suitable RNAV System. When installed in accord- ance with appropriate airworthiness installation requirements and operated in accordance with applicable operational guidance (e.g., aircraft flight manual and Advisory Circular material), the following systems qualify as a suitable RNAV system: 1. An RNAV system with TSO−C129/ −C145/−C146 equipment, installed in accordance with AC 20−138, Airworthiness Approval of Global Positioning System (GPS) Navigation Equipment for Use as a VFR and IFR Supplemental Navigation System, or AC 20−130A, Airworthiness Approval of Navigation or Flight Management Systems Integrat- ing Multiple Navigation Sensors, and authorized for instrument flight rules (IFR) en route and terminal operations (including those systems previously qualified for “GPS in lieu of ADF or DME” operations), or 2. An RNAV system with DME/DME/IRU inputs that is compliant with the equipment provisions of AC 90−100A, U.S. Terminal and En Route Area Navigation (RNAV) Operations, for RNAV routes. A table of compliant equipment is available at the following website: 0/policy_guidance/ NOTE − Approved RNAV systems using DME/DME/IRU, withoutGPS/WAAS position input, may only be used as a substitutemeans of navigation when specifically authorized by aNotice to Airmen (NOTAM) or other FAA guidance for aspecific procedure. The NOTAM or other FAA guidanceauthorizing the use of DME/DME/IRU systems will alsoidentify any required DME facilities based on an FAA assessment of the DME navigation infrastructure. c. Uses of Suitable RNAV Systems. Subject to the operating requirements, operators may use a suitable RNAV system in the following ways. 1. Determine aircraft position relative to, or distance from a VOR (see NOTE 5 below), TACAN, NDB, compass locator, DME fix; or a named fix defined by a VOR radial, TACAN course, NDB bearing, or compass locator bearing intersecting a VOR or localizer course. 2. Navigate to or from a VOR, TACAN, NDB, or compass locator. 3. Hold over a VOR, TACAN, NDB, compass locator, or DME fix. 4. Fly an arc based upon DME. NOTE − 1. The allowances described in this section apply evenwhen a facility is identified as required on a procedure (for example, “Note ADF required”). 2. These operations do not include lateral navigation on −based courses (including localizer back−course guidance) without reference to raw localizer data. 3. Unless otherwise specified, a suitable RNAV systemcannot be used for navigation on procedures that areidentified as not authorized (“NA”) without exception bya NOTAM. For example, an operator may not use a RNAVsystem to navigate on a procedure affected by an expired orunsatisfactory flight inspection, or a procedure that is based upon a recently decommissioned NAVAID. 4. Pilots may not substitute for the NAVAID (for example,a VOR or NDB) providing lateral guidance for the finalapproach segment. This restriction does not refer toinstrument approach procedures with “or GPS” in the titlewhen using GPS or WAAS. These allowances do not applyto procedures that are identified as not authorized (NA)without exception by a NOTAM, as other conditions maystill exist and result in a procedure not being available. Forexample, these allowances do not apply to a procedureassociated with an expired or unsatisfactory flightinspection, or is based upon a recently decommissioned NAVAID. 5. For the purpose of paragraph c, “VOR” includes VOR,VOR/DME, and VORTAC facilities and “compasslocator” includes locator outer marker and locator middle marker. Page 13
AIM 4/3/14 1−2−7 Area Navigation (RNAV) and Required Navigation Performance (RNP) d. Alternate Airport Considerations. For the purposes of flight planning, any required alternate airport must have an available instrument approach procedure that does not require the use of GPS. This restriction includes conducting a conventional approach at the alternate airport using a substitute means of navigation that is based upon the use of GPS. For example, these restrictions would apply when planning to use GPS equipment as a substitute means of navigation for an out−of−service VOR that supports an ILS missed approach procedure at an alternate airport. In this case, some other approach not reliant upon the use of GPS must be available. This restriction does not apply to RNAV systems using TSO−C145/−C146 WAAS equipment. For further WAAS guidance see AIM 1−1−19. 1. For flight planning purposes, TSO-C129() and TSO-C196() equipped users (GPS users) whose navigation systems have fault detection and exclusion (FDE) capability, who perform a preflight RAIM prediction at the airport where the RNAV (GPS) approach will be flown, and have proper knowledge and any required training and/or approval to conduct a GPS-based IAP, may file based on a GPS-based IAP at either the destination or the alternate airport, but not at both locations. At the alternate airport, pilots may plan for applicable alternate airport weather minimums using: (a) Lateral navigation (LNAV) or circling minimum descent altitude (MDA); (b) LNAV/vertical navigation (LNAV/ VNAV) DA, if equipped with and using approved barometric vertical navigation (baro-VNAV) equip- ment; (c) RNP 0.3 DA on an RNAV (RNP) IAP, if they are specifically authorized users using approved baro-VNAV equipment and the pilot has verified required navigation performance (RNP) availability through an approved prediction program. 2. If the above conditions cannot be met, any required alternate airport must have an approved instrument approach procedure other than GPS that is anticipated to be operational and available at the estimated time of arrival, and which the aircraft is equipped to fly. 3. This restriction does not apply to TSO-C145() and TSO-C146() equipped users (WAAS users). For further WAAS guidance see AIM 1−1−19. Page 14
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AIM 4/3/14 2−1−1 Airport Lighting Aids Chapter 2. Aeronautical Lighting and Other Airport Visual Aids Section 1. Airport Lighting Aids 2 − 1 − 1. Approach Light Systems (ALS) a. ALS provide the basic means to transition from instrument flight to visual flight for landing. Operational requirements dictate the sophistication and configuration of the approach light system for a particular runway. b. ALS are a configuration of signal lights starting at the landing threshold and extending into the approach area a distance of 2400−3000 feet for precision instrument runways and 1400−1500 feet for nonprecision instrument runways. Some systems include sequenced flashing lights which appear to the pilot as a ball of light traveling towards the runway at high speed (twice a second). (See FIG 2−1−1.) 2 − 1 − 2. Visual Glideslope Indicators a. Visual Approach Slope Indicator (VASI) 1. VASI installations may consist of either 2, 4, 6, 12, or 16 light units arranged in bars referred to as near, middle, and far bars. Most VASI installations consist of 2 bars, near and far, and may consist of 2, 4, or 12 light units. Some VASIs consist of three bars, near, middle, and far, which provide an additional visual glide path to accommodate high cockpit aircraft. This installation may consist of either 6 or 16 light units. VASI installations consisting of 2, 4, or 6 light units are located on one side of the runway, usually the left. Where the installation consists of 12 or 16 light units, the units are located on both sides of the runway. 2. Two−bar VASI installations provide one visual glide path which is normally set at 3 degrees. Three−bar VASI installations provide two visual glide paths. The lower glide path is provided by the near and middle bars and is normally set at 3 degrees while the upper glide path, provided by the middle and far bars, is normally 1 / 4 degree higher. This higher glide path is intended for use only by high cockpit aircraft to provide a sufficient threshold crossing height. Although normal glide path angles are three degrees, angles at some locations may be as high as 4.5 degrees to give proper obstacle clearance. Pilots of high performance aircraft are cautioned that use of VASI angles in excess of 3.5 degrees may cause an increase in runway length required for landing and rollout. 3. The basic principle of the VASI is that of color differentiation between red and white. Each light unit projects a beam of light having a white segment in the upper part of the beam and red segment in the lower part of the beam. The light units are arranged so that the pilot using the VASIs during an approach will see the combination of lights shown below. 4. The VASI is a system of lights so arranged to provide visual descent guidance information during the approach to a runway. These lights are visible from 3−5 miles during the day and up to 20 miles or more at night. The visual glide path of the VASI provides safe obstruction clearance within plus or minus 10 degrees of the extended runway centerline and to 4 NM from the runway threshold. Descent, using the VASI, should not be initiated until the aircraft is visually aligned with the runway. Lateral course guidance is provided by the runway or runway lights. In certain circumstances, the safe obstruction clearance area may be reduced due to local limitations, or the VASI may be offset from the extended runway centerline. This will be noted in the Airport/ Facility Directory. Page 16
AIM 4/3/14 2−1−2 Airport Lighting Aids FIG 2 −1−1 Precision & Nonprecision Configurations NOTE − Civil ALSF −2 may be operated as SSALR during favorable weather conditions. Page 17
AIM 4/3/14 2−1−3 Airport Lighting Aids 5. For 2−bar VASI (4 light units) see FIG 2−1−2. FIG 2 −1−2 2 −Bar VASI Far Bar = Red = White Near Bar Below Glide Path On Glide Path Above Glide Path 6. For 3−bar VASI (6 light units) see FIG 2−1−3. FIG 2 −1−3 3 −Bar VASI Far Bar Middle Bar Near Bar Below Both On Lower On Upper Above Both 7. For other VASI configurations see FIG 2−1−4. FIG 2 −1−4 VASI Variations 2 Bar 2 Light Units On Glide Path 2 Bar 12 Light Units On Glide Path 3 Bar 16 Light Units on Lower Glide Path Page 18
AIM 4/3/14 2−1−4 Airport Lighting Aids b. Precision Approach Path Indicator (PAPI). The precision approach path indicator (PAPI) uses light units similar to the VASI but are installed in a single row of either two or four light units. These lights are visible from about 5 miles during the day and up to 20 miles at night. The visual glide path of the PAPI typically provides safe obstruction clearance within plus or minus 10 degrees of the extended runway centerline and to 4 SM from the runway threshold. Descent, using the PAPI, should not be initiated until the aircraft is visually aligned with the runway. The row of light units is normally installed on the left side of the runway and the glide path indications are as depicted. Lateral course guidance is provided by the runway or runway lights. In certain circumstances, the safe obstruction clearance area may be reduced due to local limitations, or the PAPI may be offset from the extended runway centerline. This will be noted in the Airport/ Facility Directory. (See FIG 2−1−5.) FIG 2 −1−5 Precision Approach Path Indicator (PAPI) Slightly High (3.2 Degrees) White Red High (More Than 3,5 Degrees) On Glide Path (3 Degrees) Slightly Low (2.8 Degrees) Low (Less Than 2.5 Degrees) c. Tri −color Systems. Tri−color visual approach slope indicators normally consist of a single light unit projecting a three−color visual approach path into the final approach area of the runway upon which the indicator is installed. The below glide path indication is red, the above glide path indication is amber, and the on glide path indication is green. These types of indicators have a useful range of approximately one−half to one mile during the day and up to five miles at night depending upon the visibility conditions. (See FIG 2−1−6.) FIG 2 −1−6 Tri −Color Visual Approach Slope Indicator Amber Above Glide Path On Glide Path Below Glide Path Amber Green Red NOTE − 1. Since the tri −color VASI consists of a single light source which could possibly be confused with other light sources, pilots should exercise care to properly locate and identify the light signal. 2. When the aircraft descends from green to red, the pilot may see a dark amber color during the transition from green to Page 19
AIM 4/3/14 2−1−5 Airport Lighting Aids FIG 2 −1−7 Pulsating Visual Approach Slope Indicator Above Glide Path On Glide Path Below Glide Path Slightly Below Glide Path Threshold PULSATING WHITE PULSATING RED STEADY WHITE STEADY RED NOTE − Since the PVASI consists of a single light source which could possibly be confused with other light sources, pilots should FIG 2 −1−8 Alignment of Elements Below Glide Path On Glide Path Above Glide Path d. Pulsating Systems. Pulsating visual ap- proach slope indicators normally consist of a single light unit projecting a two−color visual approach path into the final approach area of the runway upon which the indicator is installed. The on glide path indication is a steady white light. The slightly below glide path indication is a steady red light. If the aircraft descends further below the glide path, the red light starts to pulsate. The above glide path indication is a pulsating white light. The pulsating rate increases as the aircraft gets further above or below the desired glide slope. The useful range of the system is about four miles during the day and up to ten miles at night. (See FIG 2−1−7.) e. Alignment of Elements Systems. Alignment of elements systems are installed on some small general aviation airports and are a low−cost system consisting of painted plywood panels, normally black and white or fluorescent orange. Some of these systems are lighted for night use. The useful range of these systems is approximately three−quarter miles. To use the system the pilot positions the aircraft so the Page 20
AIM 4/3/14 2−1−6 Airport Lighting Aids elements are in alignment. The glide path indications are shown in FIG 2−1−8. 2 − 1 − 3. Runway End Identifier Lights (REIL) REILs are installed at many airfields to provide rapid and positive identification of the approach end of a particular runway. The system consists of a pair of synchronized flashing lights located laterally on each side of the runway threshold. REILs may be either omnidirectional or unidirectional facing the approach area. They are effective for: a. Identification of a runway surrounded by a preponderance of other lighting. b. Identification of a runway which lacks contrast with surrounding terrain. c. Identification of a runway during reduced visibility. 2 − 1 − 4. Runway Edge Light Systems a. Runway edge lights are used to outline the edges of runways during periods of darkness or restricted visibility conditions. These light systems are classified according to the intensity or brightness they are capable of producing: they are the High Intensity Runway Lights (HIRL), Medium Intensity Runway Lights (MIRL), and the Low Intensity Runway Lights (LIRL). The HIRL and MIRL systems have variable intensity controls, whereas the LIRLs normally have one intensity setting. b. The runway edge lights are white, except on instrument runways yellow replaces white on the last 2,000 feet or half the runway length, whichever is less, to form a caution zone for landings. c. The lights marking the ends of the runway emit red light toward the runway to indicate the end of runway to a departing aircraft and emit green outward from the runway end to indicate the threshold to landing aircraft. 2 − 1 − 5. In − runway Lighting a. Runway Centerline Lighting System (RCLS). Runway centerline lights are installed on some precision approach runways to facilitate landing under adverse visibility conditions. They are located along the runway centerline and are spaced at 50−foot intervals. When viewed from the landing threshold, the runway centerline lights are white until the last 3,000 feet of the runway. The white lights begin to alternate with red for the next 2,000 feet, and for the last 1,000 feet of the runway, all centerline lights are red. b. Touchdown Zone Lights (TDZL). Touch- down zone lights are installed on some precision approach runways to indicate the touchdown zone when landing under adverse visibility conditions. They consist of two rows of transverse light bars disposed symmetrically about the runway centerline. The system consists of steady−burning white lights which start 100 feet beyond the landing threshold and extend to 3,000 feet beyond the landing threshold or to the midpoint of the runway, whichever is less. c. Taxiway Centerline Lead −Off Lights. Taxi- way centerline lead−off lights provide visual guidance to persons exiting the runway. They are color−coded to warn pilots and vehicle drivers that they are within the runway environment or instrument landing system/microwave landing sys- tem (ILS/MLS) critical area, whichever is more restrictive. Alternate green and yellow lights are installed, beginning with green, from the runway centerline to one centerline light position beyond the runway holding position or ILS/MLS critical area holding position. d. Taxiway Centerline Lead −On Lights. Taxi- way centerline lead−on lights provide visual guidance to persons entering the runway. These “lead−on” lights are also color−coded with the same color pattern as lead−off lights to warn pilots and vehicle drivers that they are within the runway environment or instrument landing system/micro- wave landing system (ILS/MLS) critical area, whichever is more conservative. The fixtures used for lead−on lights are bidirectional, i.e., one side emits light for the lead−on function while the other side emits light for the lead−off function. Any fixture that emits yellow light for the lead−off function must also emit yellow light for the lead−on function. (See FIG 2−1−14.) e. Land and Hold Short Lights. Land and hold short lights are used to indicate the hold short point on certain runways which are approved for Land and Hold Short Operations (LAHSO). Land and hold short lights consist of a row of pulsing white lights installed across the runway at the hold short point. Where installed, the lights will be on anytime Page 21
AIM 4/3/14 2−1−7 Airport Lighting Aids LAHSO is in effect. These lights will be off when LAHSO is not in effect. REFERENCE − AIM, Pilot Responsibilities When Conducting Land and Hold Short −3−11. 2 − 1 − 6. Runway Status Light (RWSL) System a. Introduction. RWSL is a fully automated system that provides runway status information to pilots and surface vehicle operators to clearly indicate when it is unsafe to enter, cross, takeoff from, or land on a runway. The RWSL system processes information from surveil- lance systems and activates Runway Entrance Lights (REL), Takeoff Hold Lights (THL), Runway Intersection Lights (RIL), and Final Approach Runway Occupancy Signal (FAROS) in accordance with the position and velocity of the detected surface traffic and approach traffic. REL, THL, and RIL are in-pavement light fixtures that are directly visible to pilots and surface vehicle operators. FAROS alerts arriving pilots that the approaching runway is occupied by flashing the Precision Approach Path Indicator (PAPI). FAROS may be implemented as an add-on to the RWSL system or implemented as a stand-alone system at airports without a RWSL system. RWSL is an independent safety enhancement that does not substitute for or convey an ATC clearance. Clearance to enter, cross, takeoff from, land on, or operate on a runway must still be received from ATC. Although ATC has limited control over the system, personnel do not directly use and may not be able to view light fixture activations and deactivations during the conduct of daily ATC operations. b. Runway Entrance Lights (REL): The REL system is composed of flush mounted, in-pavement, unidirectional light fixtures that are parallel to and focused along the taxiway centerline and directed toward the pilot at the hold line. An array of REL lights include the first light at the hold line followed by a series of evenly spaced lights to the runway edge; one additional light at the runway centerline is in line with the last two lights before the runway edge (see FIG 2−1−9 and FIG 2−1−12). When activated, the red lights indicate that there is high speed traffic on the runway or there is an aircraft on final approach within the activation area. 1. REL Operating Characteristics − Departing Aircraft: When a departing aircraft reaches a site adaptable speed of approximately 30 knots, all taxiway intersections with REL arrays along the runway ahead of the aircraft will illuminate (see FIG 2−1−9). As the aircraft approaches an REL equipped taxiway intersection, the lights at that intersection extinguish approximately 3 to 4 seconds before the aircraft reaches it. This allows controllers to apply “anticipated separation” to permit ATC to move traffic more expeditiously without compromising safety. After the aircraft is declared “airborne” by the system, all REL lights associated with this runway will extinguish. 2. REL Operating Characteristics − Arriving Aircraft: When an aircraft on final approach is approximately 1 mile from the runway threshold, all sets of taxiway REL light arrays that intersect the runway illuminate. The distance is adjustable and can be configured for specific operations at particular airports. Lights extinguish at each equipped taxiway intersection approximately 3 to 4 seconds before the aircraft reaches it to apply anticipated separation until the aircraft has slowed to approximately 80 knots (site adjustable parameter). Below 80 knots, all arrays that are not within 30 seconds of the aircraft’s forward path are extinguished. Once the arriving aircraft slows to approximately 34 knots (site adjustable parameter), it is declared to be in a taxi state, and all lights extinguish. 3. What a pilot would observe: A pilot at or approaching the hold line to a runway will observe RELs illuminate and extinguish in reaction to an aircraft or vehicle operating on the runway, or an arriving aircraft operating less than 1 mile from the runway threshold. 4. When a pilot observes the red lights of the REL, that pilot will stop at the hold line or remain stopped. The pilot will then contact ATC for resolution if the clearance is in conflict with the lights. Should pilots note illuminated lights under circumstances when remaining clear of the runway is impractical for safety reasons (for example, aircraft is already on the runway), the crew should proceed according to their best judgment while understanding the illuminated lights indicate the runway is unsafe to Page 22
AIM 4/3/14 2−1−8 Airport Lighting Aids enter or cross. Contact ATC at the earliest possible opportunity. FIG 2 −1−9 Runway Status Light System c. Takeoff Hold Lights (THL) : The THL system is composed of flush mounted, in-pavement, unidirectional light fixtures in a double longitudinal row aligned either side of the runway centerline lighting. Fixtures are focused toward the arrival end of the runway at the “line up and wait” point. THLs extend for 1,500 feet in front of the holding aircraft starting at a point 375 feet from the departure threshold (see FIG 2−1−13). Illuminated red lights provide a signal, to an aircraft in position for takeoff or rolling, that it is unsafe to takeoff because the runway is occupied or about to be occupied by another aircraft or ground vehicle. Two aircraft, or a surface vehicle and an aircraft, are required for the lights to illuminate. The departing aircraft must be in position for takeoff or beginning takeoff roll. Another aircraft or a surface vehicle must be on or about to cross the runway. 1. THL Operating Characteristics − Departing Aircraft: THLs will illuminate for an aircraft in position for departure or departing when there is another aircraft or vehicle on the runway or about to enter the runway (see FIG 2−1−9.) Once that aircraft or vehicle exits the runway, the THLs extinguish. A pilot may notice lights extinguish prior to the downfield aircraft or vehicle being completely clear of the runway but still moving. Like RELs, THLs have an “anticipated separation” feature. NOTE − When the THLs extinguish, this is not clearance to begin a 2. What a pilot would observe: A pilot in position to depart from a runway, or has begun takeoff roll, will observe THLs illuminate in reaction to an aircraft or vehicle on the runway or entering or crossing it. Lights will extinguish when the runway is clear. A pilot may observe several cycles of illumination and extinguishing depending on the amount of crossing traffic. 3. When a pilot observes the red light of the THLs, the pilot should safely stop if it’s feasible or remain stopped. The pilot must contact ATC for resolution if any clearance is in conflict with the lights. Should pilots note illuminated lights while in takeoff roll and under circumstances when stopping is impractical for safety reasons, the crew should Page 23
AIM 4/3/14 2−1−9 Airport Lighting Aids proceed according to their best judgment while understanding the illuminated lights indicate that continuing the takeoff is unsafe. Contact ATC at the earliest possible opportunity. d. Runway Intersection Lights (RIL): The RIL system is composed of flush mounted, in−pavement, unidirectional light fixtures in a double longitudinal row aligned either side of the runway centerline lighting in the same manner as THLs. Their appearance to a pilot is similar to that of THLs. Fixtures are focused toward the arrival end of the runway, and they extend for 3,000 feet in front of an aircraft that is approaching an intersecting runway. They end at the Land and Hold Short Operation (LASHO) light bar or the hold short line for the intersecting runway. 1. RIL Operating Characteristics − Departing Aircraft: RILs will illuminate for an aircraft departing or in position to depart when there is high speed traffic operating on the intersecting runway (see FIG 2−1−9). Note that there must be an aircraft or vehicle in a position to observe the RILs for them to illuminate. Once the conflicting traffic passes through the intersection, the RILs extinguish. 2. RIL Operating Characteristics − Arriving Aircraft: RILs will illuminate for an aircraft that has landed and is rolling out when there is high speed traffic on the intersecting runway that is $5 seconds of meeting at the intersection. Once the conflicting traffic passes through the intersection, the RILs extinguish. 3. What a pilot would observe: A pilot departing or arriving will observe RILs illuminate in reaction to the high speed traffic operation on the intersecting runway. The lights will extinguish when that traffic has passed through the runway intersection. 4. Whenever a pilot observes the red light of the RIL array, the pilot will stop before the LAHSO stop bar or the hold line for the intersecting runway. If a departing aircraft is already at high speed in the takeoff roll when the RILs illuminate, it may be impractical to stop for safety reasons. The crew should safely operate according to their best judgment while understanding the illuminated lights indicate that continuing the takeoff is unsafe. Contact ATC at the earliest possible opportunity. e. The Final Approach Runway Occupancy Signal (FAROS) is communicated by flashing of the Precision Approach Path Indicator (PAPI) (see FIG 2-1-9). When activated, the light fixtures of the PAPI flash or pulse to indicate to the pilot on an approach that the runway is occupied and that it may be unsafe to land. NOTE − FAROS is an independent automatic alerting system that 1. FAROS Operating Characteristics: If an aircraft or surface vehicle occupies a FAROS equipped runway, the PAPI(s) on that runway will flash. The glide path indication will not be affected, and the allotment of red and white PAPI lights observed by the pilot on approach will not change. The FAROS system will flash the PAPI when traffic enters the runway and there is an aircraft on approach and within 1.5 nautical miles of the landing threshold. 2. What a pilot would observe: A pilot on approach to the runway will observe the PAPI flash if there is traffic on the runway and will notice the PAPI ceases to flash when the traffic moves outside the hold short lines for the runway. 3. When a pilot observes a flashing PAPI at 500 feet above ground level (AGL), the contact height, the pilot must look for and acquire the traffic on the runway. At 300 feet AGL, the pilot must contact ATC for resolution if the FAROS indication is in conflict with the clearance. If the PAPI continues to flash, the pilot must execute an immediate “go around” and contact ATC at the earliest possible opportunity. f. Pilot Actions: 1. When operating at airports with RWSL, pilots will operate with the transponder “On” when departing the gate or parking area until it is shutdown upon arrival at the gate or parking area. This ensures interaction with the FAA surveillance systems such as ASDE-X which provide information to the RWSL system. 2. Pilots must always inform the ATCT when they have either stopped, are verifying a landing clearance, or are executing a go-around due to RWSL or FAROS indication that are in conflict with ATC instructions. Pilots must request clarification of the taxi, takeoff, or landing clearance. 3. Never cross over illuminated red lights. Under normal circumstances, RWSL will confirm the Page 24
AIM 4/3/14 2−1−10 Airport Lighting Aids pilot’s taxi or takeoff clearance previously issued by ATC. If RWSL indicates that it is unsafe to takeoff from, land on, cross, or enter a runway, immediately notify ATC of the conflict and re-confirm the clearance. 4. Do not proceed when lights have extin- guished without an ATC clearance. RWSL verifies an ATC clearance; it does not substitute for an ATC clearance. 5. Never land if PAPI continues to flash. Execute a go around and notify ATC. g. ATC Control of RWSL System: 1. Controllers can set in−pavement lights to one of five (5) brightness levels to assure maximum conspicuity under all visibility and lighting condi- tions. REL, THL, and RIL subsystems may be independently set. 2. System lights can be disabled should RWSL operations impact the efficient movement of air traffic or contribute, in the opinion of the assigned ATC Manager, to unsafe operations. REL, THL, RIL, and FAROS light fixtures may be disabled separately. Disabling of the FAROS subsystem does not extinguish PAPI lights or impact its glide path function. Whenever the system or a component is disabled, a NOTAM must be issued, and the Automatic Terminal Information System (ATIS) must be updated. 2 − 1 − 7. Stand-Alone Final Approach Runway Occupancy Signal (FAROS) a. Introduction: The stand-alone FAROS system is a fully automated system that provides runway occupancy status to pilots on final approach to indicate whether it may be unsafe to land. When an aircraft or vehicle is detected on the runway, the Precision Approach Path Indicator (PAPI) light fixtures flash as a signal to indicate that the runway is occupied and that it may be unsafe to land. The stand-alone FAROS system is activated by localized or comprehensive sensors detecting aircraft or ground vehicles occupying activation zones. areas of the runway, called activation zones, to determine the presence of aircraft or ground vehicles in the zone (see FIG 2−1−10). These activation zones are defined as areas on the runway that are frequently occupied by ground traffic during normal airport operations and could present a hazard to landing aircraft. Activation zones may include the full-length departure position, the midfield departure position, a frequently crossed intersection, or the entire runway. information sheet for activation zone configuration. FIG 2 −1−10 FAROS Activation Zones Clearance to land on a runway must be issued by Air Traffic Control (ATC). ATC personnel have limited control over the system and may not be able to view the FAROS signal. Page 25
AIM 4/3/14 2−1−11 Airport Lighting Aids b. Operating Characteristics: If an aircraft or ground vehicle occupies an activation zone on the runway, the PAPI light fixtures on that runway will flash. The glide path indication is not affected, i.e. the configuration of red and white PAPI lights observed by the pilot on approach does not change. The stand-alone FAROS system flashes the PAPI lights when traffic occupies an activation zone whether or not there is an aircraft on approach. c. Pilot Observations: A pilot on approach to the runway observes the PAPI lights flashing if there is traffic on the runway activation zones and notices the PAPI lights cease to flash when the traffic moves outside the activation zones. A pilot on departure from the runway should disregard any observations of flashing PAPI lights. d. Pilot Actions: When a pilot observes a flashing PAPI at 500 feet above ground level (AGL), the pilot must look for and attempt to acquire the traffic on the runway. At 300 feet AGL, the pilot must contact ATC for resolution if the FAROS indication is in conflict with the clearance (see FIG 2−1−11). If the PAPI lights continue to flash and the pilot cannot visually determine that it is safe to land, the pilot must execute an immediate “go around”. As with operations at non-FAROS airports, it is always the pilot’s responsibility to determine whether or not it is safe to continue with the approach and to land on the runway. FIG 2 −1−11 FAROS Glide Slope Action Points Pilots should inform the ATCT when they have executed a go around due to a FAROS indication that is in conflict with ATC instructions. NOTE − At this time, the stand-alone FAROS system is not widely 2 − 1 − 8. Control of Lighting Systems a. Operation of approach light systems and runway lighting is controlled by the control tower (ATCT). At some locations the FSS may control the lights where there is no control tower in operation. b. Pilots may request that lights be turned on or off. Runway edge lights, in−pavement lights and approach lights also have intensity controls which may be varied to meet the pilots request. Sequenced flashing lights (SFL) may be turned on and off. Some sequenced flashing light systems also have intensity control. 2 − 1 − 9. Pilot Control of Airport Lighting Radio control of lighting is available at selected airports to provide airborne control of lights by keying the aircraft’s microphone. Control of lighting systems is often available at locations without specified hours for lighting and where there is no control tower or FSS or when the tower or FSS is closed (locations with a part−time tower or FSS) or specified hours. All lighting systems which are radio controlled at an airport, whether on a single runway or multiple runways, operate on the same radio frequency. (See TBL 2−1−1 and TBL 2−1−2.) Page 26
AIM 4/3/14 2−1−12 Airport Lighting Aids FIG 2 −1−12 Runway Entrance Lights FIG 2 −1−13 Takeoff Hold Lights |
What does Unrel indicate in the following GPS and WAAS notam?
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