Section 3. NAVAID NOTAMs

1. GENERAL

Technical Operations personnel must ensure the origination of NOTAM Ds concerning NAVAIDs for which they are responsible.

1. REPORTING NAVAID MALFUNCTIONS

Known or reported malfunctions of a navigational aid must be reported to Technical Operations or appropriate personnel.

1. UNPROGRAMMED EXTENDED SHUTDOWNS

Unprogrammed, extended facility shutdowns or other unanticipated outages that are expected to last more than 30 days must be promptly reported to the Aeronautical Data Team. When possible, the expected duration of the shutdown is to be included in the message. Except for emergency shutdowns, technical operations personnel are expected to give at least 1 hour notice.

1. NAVAID MAINTENANCE SHUTDOWNS

Information concerning maintenance shutdown of NAVAIDs that are part of the NAS must be handled as follows:

1. Routine maintenance shutdown. When possible, approval should be obtained sufficiently in advance of the proposed shutdown time to allow dissemination of a NOTAM at least 5 hours before a shutdown will occur. A routine maintenance shutdown request must not be denied because of an inability to issue a NOTAM 5 hours in advance of the shutdown.
2. Emergency shutdown. When possible, obtain at least 1-hour advance notice so that appropriate dissemination may be made before shutdown.
3. Extended maintenance shutdown. Notify the Aeronautical Data Team sufficiently in advance to permit publication of the information prior to the shutdown date. When this is not possible, disseminate a NOTAM no more than 7 days before the shutdown.

1. UNMONITORED NAVAIDs

1. All VOR, VORTAC, and ILS equipment in the NAS have automatic monitoring and shutdown features in the event of malfunction.
2. When a navigational aid's operational status cannot be monitored at the controlling or monitoring facility, but all indications or reports are the facility is operating normally, Technical Operations personnel must ensure the origination of a NOTAM placing the aid in an unmonitored status.
3. When issuing a NOTAM describing a facility as unmonitored, do not use the category of monitor, only the phrase “NOT MNT.”
4. Do not issue a NOTAM for a standalone DME that is not monitored.
5. If the NAVAID is reported as being unserviceable, the unmonitored NOTAM must be canceled.

1. INSTRUMENT LANDING SYSTEM STATUS

1. Technical Operations issue NOTAMs related to outages or restrictions for all ILS equipment and components that they own/maintain/certify, regardless of duration. AIS 24/7 NOTAM Center is responsible for issuing any procedural NOTAMs, such as flight data center (FDC) NOTAMs. Consult FAA Order 6750.24 to determine if any additional NOTAM Ds should be issued. Ideally, a NOTAM will allow authorized operators to continue, while notifying unauthorized operators that the specified approach procedure is not available. It is critical that required NOTAMs alert users of an inoperative facility or system. In some situations, an all-encompassing cancellation of specific minima (e.g., “CAT II/III Not Authorized”) may not be necessary.
2. Category II and/or III approaches may not be authorized due to the failure of additional equipment, as specified in FAA Order 6750.24. The Technical Operations Control Center specialist in accordance with the guidance contained in FAA Order 6750.24 will make the determination of impact to Category II/III ILS operations, and a separate NOTAM request for loss of ILS category will be made if the equipment failures warrant this action.
3. When Technical Operations personnel issue a NOTAM suspending CAT II/III minimums, AIS must be notified. If the suspension will exist longer than 224-days or is permanent, AIS must submit a full or abbreviated procedure amendment prior to the 224-day suspense.
4. Special Authorization CAT I/II approaches. These Part 97 CAT I/II approaches are identified as “ILS RWY XX (SA CAT I) or ILS RWY XX (SA CAT II)” and by an additional chart note saying “Reduced Lighting: Requires specific OpSpec, MSpec, or LOA approval.”

1. The aircraft operator is authorized to conduct CAT I/II IAP on certain ILS facilities that do not meet the equipment requirements of a U.S. Standard or ICAO Standard, for example when TDZ lighting or RCL become inoperative. These procedures have been specifically approved in accordance with FAA Order 8400.13, Procedures for the Evaluation and Approval of Facilities for Special Authorization Category I Operations and All Category II and III Operations.
2. When TDZ and/or CL lighting become inoperative on a standard CAT II instrument approach, the certificate holder is authorized to conduct SA CAT II operations.

1. NAVAID CONDITIONS

…NAV VOR 090-180 BEYOND 25NM SFC-5000FT, 270-300 BEYOND 25NM SFC-5000FT, 301-360 BEYOND 35NM SFC-4000FT UNUSABLE…

See Appendix A for examples.

1. Introduction. Facility status classification and NOTAM(s) will indicate restriction(s) to the expected use of these facilities. The NOTAM advises the user of any restriction to facility usage. If the NAVAID is out of service or unmonitored, the VOICE is automatically out of service.
2. Facility Status Classification.
   Operational Status. The legal facility status of Usable or Unusable is broken down as follows:

1. Usable. The facility is available for operational use and is either.

1. Unrestricted. Providing safe, accurate signals-in-space conforming to established standards within the coverage area of the facility.
2. Restricted. Providing signals-in-space not conforming to established standards in all respects or in all sectors of the coverage area, but safe for use excluding the restrictions defined.

1. Unusable. The facility is not available for operational use because it may provide potentially unsafe or erroneous signals, or signals of unknown quality. When describing visual aids, this term is used only by Flight Inspection.

1. NOTAM(s).

1. General. Originate a NOTAM D for commissioning, decommissioning, outages, or unmonitored status of radio navigation aids (60 minutes or more) that are part of the NAS. The NOTAM must be cancelled by the originator. An exception is that Technical Operations will originate a NOTAM for all Instrument Landing System Equipment and components for all associated outages regardless of duration. When a flight inspection necessitates NOTAM action, the flight inspector is responsible for initiating the NOTAM(s). The flight inspector must verify within 24 hours that the appropriate NOTAM(s) were issued, amended, or cancelled. The inspector must verify that NOTAM(s) are published in the appropriate agency publication.
2. Facility NOTAM D. The inspector must immediately initiate NOTAM action whenever a facility restriction is found or revised.
3. Initiating FDC NOTAM(s). FDC NOTAM(s) must be issued if a restriction affects instrument flight procedures, approach minimums, or category (CAT) II or III authorizations. Internal processes are in place between the Oklahoma City Service Center (OKC SC), the National Operations Control Center (NOCC), and Aeronautical Information Services (AIS) to ensure FDC NOTAM(s) resulting from reported facility outages, flight inspection results, or restriction changes are issued. The NOCC automatically notifies the AIS when there is a facility outage or restoration. The OKC SC will notify AIS when a flight inspection results in a new or canceled facility restriction.
4. Expanded Service Volume (ESV). When a facility no longer supports a particular ESV, an FDC NOTAM must be issued for each published instrument flight procedure that requires that ESV.
5. Preparation of NOTAM(s).

1. NOTAM(s) must include facility name, type, component, and the unusable area/altitude. The absence of a specific altitude or distance denotes all altitudes and distances. It is important to include specific information to avoid confusion. The reason for the restriction (e.g., lack of signal, frequency interference, course structure, alignment, unlocks) serves no useful purpose and must not be included in the text of the NOTAM.
2. Restrictions to VORTAC and TACAN facilities are issued via NOTAM D, including TACAN azimuth restrictions. The NOTAM preparation for the TACAN azimuth component of a VORTAC is identical to the VOR.

1. Facility Restrictions. Restrictions to NAVAIDs are normally published by segment: for example, 020-055 degree radials. To correct a given segment, cancel the original NOTAM and issue a completely new NOTAM. Every effort should be made to restrict rather than remove from service a facility, or instrument procedure, when out of tolerance conditions are found. Describe lateral restrictions in a clock-wise (CW) direction. The following illustrate the most common applications for Flight Inspection.

1. General. When defining altitude restrictions, use the format, “SFC - XXXXFT,” where “SFC” stands for surface and XXXXFT is the top of the restriction in MSL altitude. Altitude restrictions recorded on data sheets, Flight Inspection reports, Airport/NAVAID (AIRNAV) database, and in the Chart Supplement, will use the standard flight inspection format of, “unusable below (altitude), or “unusable above (altitude),” as appropriate. The listed altitude is the usable MSL altitude. Only NOTAM(s) will use the “SFC-XXXXFT” format. For example: a VOR found unusable below 3000FT MSL would result in a NOTAM that lists the restriction as unusable “SFC-2900FT.” Use a 100FT increment from the “usable” altitude to describe the first “unusable” altitude.
2. Excessive snow and ice accumulation near the glide slope antennas may affect facility performance to the extent that it is inoperative. When this occurs, Technical Operations personnel at the glide slope location are required to initiate appropriate NOTAM D action. Technical operations personnel must monitor snow conditions to determine when conditions permit use of the glide slope and initiate action to cancel the NOTAM. Technical Operations and Aeronautical Information Services NOTAM Office make the determination when to issue an FDC NOTAM or NOTAM D, based on FAA JO 6750.49, Maintenance of Instrument Landing System (ILS) Facilities. Tech Ops issues the NOTAM D and AIS 24/7 NOTAM Center issues the FDC.
3. VOR/ TACAN/DME/ VOT/ NDB/ DF. Describe radial/ bearing from the station in a clockwise direction, altitude in terms of above or below an MSL altitude, and distance in terms of beyond or within a nautical mile distance. When defining a restriction adjacent to another in azimuth, the same radial should not be contained in both restrictions. For example: don't state “020-090 and 090-110”, but rather state either, “020-090 and 091-110”, or “020-089 and 090-110.”

1. When describing restrictions to these kind of facilities:

1. Describe the radials or bearings that are unusable.
2. Describe the mileage point beyond which the facility is unusable.
3. Describe any altitude restriction using the NOTAM format.

1. Follow this guidance for identifying specific components:

1. VOR/DME. Reference “VOR/DME” when the restriction simultaneously applies to both the VOR and DME performance. Just use “VOR” if the restriction only applies to the VOR component, and “DME” if it only applies to the DME component.
2. VORTAC. Reference “VORTAC” when all components (VOR, TACAN AZM, and DME) are being restricted together. Reference the individual component if the restriction only applies to that component.

1. VOT (VOR Test Facility).
2. VOR Receiver Checkpoint. There are airborne receiver checkpoints (VOR AIRBORNE REC CHECKPOINT) and ground receiver checkpoints (VOR GND REC CHECKPOINT).

1. TVOR (Terminal Class VOR).

1. TVORs serving one airport, and not associated with airway structure, must have NOTAMs issued using the associated airport identifier as the affected facility.
2. TVORs serving more than one airport, or associated with airway structure, must have NOTAMs issued using the TVOR identifier as the affected facility.

1. NDB outages:

1. Terminal NDBs. Those NDBs located on or serving only that airport must have NOTAMs issued using the associated airport as the affected facility.
2. If an NDB serves more than one airport, or associated with an airway route structure, issue a NOTAM using the identifier of the NDB as the affected facility.

1. LOM outages.

1. LOM serving one airport must be issued with the three-letter identifier of the airport as the location identifier.
2. LOM serving more than one airport must be issued under the three-letter identifier of each airport that it serves. This procedure may require coordination with other facilities.

1. NAVAID identification change. (See example in Appendix A).

1. Visual Glide Slope Indicator. Describe in terms of nautical miles from threshold and/or degrees left and right of runway centerline any areas of coverage where the facility is unusable.
2. A DME can be a separate facility, or a facility associated with an ILS, LOC, LOC Type Directional Aid, Simplified Direction Finder, NDB and VOR. When a DME is a separate system (a DME-only facility), the only condition is unserviceable. Restrictions are not published for DME-only facilities.
3. Instrument Landing Systems (ILS).

…NAV ILS RWY 12 LOC UNUSABLE BEYOND 4DEG RIGHT OF COURSE…

1. Distinguish components of an ILS from non-precision approach NAVAIDs by preceding the component with “ILS” followed by “RWY” and the runway number (including single ILS airports). Use the term “COURSE” when describing radio navigation aid restrictions. Coupled approach restrictions (for ILS CAT I) are issued via FDC NOTAM.

1. NOTAMS on a localizer backcourse (BC) may be issued for both outages and restrictions. A backcourse facility may be completely separate from front course operations.

1. Glide Slope Elevation. Describe in terms of degrees left or right of inbound course and nautical miles from threshold; Describe unusable altitudes in terms of surface to the lowest usable MSL altitude or as unusable above a highest usable MSL altitude. Ensure the restriction correctly reflects the service volume origin. Additional reference to DME distances may be used if the DME is part of the approach procedure.

1. Localizer/LOC Directional Aid/Simplified Directional Facility Azimuth. There are runways equipped with a localizer facility without a glide slope, and are not designated an ILS.

1. Lateral Restriction: Lateral restrictions are measured in degrees left or right of inbound course.
2. Remaining Distance Restriction: Restriction occurs in the remaining distance to the runway, expressed in nautical miles from the runway threshold. For example, the localizer is unusable within 0.3 NM of the threshold.
3. Usable Distance Restriction: Restrictions affecting the usable distance of the facility are measured in nautical miles from the antenna. For example, the localizer is unusable beyond 15 NM.

1. Modifying an existing facility NOTAM. When a new facility restriction modifies an existing restriction, add “PLUS SEE (publication)” when other valid restrictions to the NAVAID are published. The absence of this statement from the NOTAM indicates that all other restrictions have been canceled.
   Flight Inspection Work Flow Process:

1. Given a VOR/DME with the published (not NOTAMs) restrictions of:
     VOR Unusable: 005-040 BEYOND 27NM SFC-13000FT
     VOR Unusable: 325-040 BEYOND 20NM SFC-10500FT
2. And during a subsequent flight inspection it is determined that the previous restriction of 005-040 BEYOND 27NM SFC-13000FT must be moved in and raised so it now reads 005-040 BEYOND 25NM SFC-14000FT. First, cancel the existing restriction:
   [CANCEL:] VOR 005-040 BEYOND 27NM SFC-12900FT UNUSABLE.
3. Next, issue the NOTAM with the new restriction with the addition of “PLUS SEE”:
   …VOR 005-040 BEYOND 25NM SFC-13900FT UNUSABLE PLUS SEE CHART SUPPLEMENT…

1. NOTAM Scenarios. The following are illustrations of conditions and prescribed NOTAM(s):

1. All components of a VORTAC are unusable in a specific sector. For example, beyond 25NM and below 3500FT MSL due to out-of-tolerance VOR and TACAN course structure and unusable DME.
   NOTAM: …NAV VORTAC 025-075 BEYOND 25NM SFC-3400FT UNUSABLE…
2. The VOR and TACAN azimuth signals of a VORTAC are unusable in a specific sector. For example, beyond 25 NM and below 3500FT MSL due to out-of-tolerance conditions, and the DME is unaffected. Issue separate NOTAMs for each component.
   NOTAM: …NAV VOR 025-075 BEYOND 25NM SFC-3400FT UNUSABLE...
   NOTAM: …NAV TACAN AZM 025-075 BEYOND 25NM SFC-3400FT UNUSABLE…
3. A VOR does not provide adequate signal within the standard service volume at the required altitudes in various areas sectors. For example, the VOR is unusable 080° CW to 100° beyond 18 NM below 3500FT MSL, and is unusable from 101° CW to 200° beyond 30 NM below 4500FT MSL.
   NOTAM: …NAV VOR 080-100 BEYOND 18NM SFC-3400FT, 101-200 BEYOND 30NM SFC-4400FT UNUSABLE…
4. A VOR is unusable in various areas below one altitude, and the DME is unusable in one sector. For example, the VOR is unusable below 1,700FT MSL in the following areas: 250° CW 265° beyond 17 NM; 266° CW 280° beyond 10 NM; and 281° CW 290° beyond 17 NM. DME unusable 225° CW 275° in the following areas: Beyond 15 NM below 2,400FT MSL and beyond 30 NM below 5,000FT MSL.
   NOTAM: …NAV VOR 250-265 BEYOND 17NM, 266-280 BEYOND 10NM, 281-290 BEYOND 17NM SFC-1600FT UNUSABLE…
   NOTAM: …NAV DME 225-275 BEYOND 15NM SFC-2300FT UNUSABLE…
   NOTAM: …NAV DME 225-275 BEYOND 30NM SFC-4900FT UNUSABLE…
5. A Nondirectional radio beacon is not usable at all altitudes beyond a certain distance in a sector. For example, the signal is unusable in the SE quadrant beyond 15 NM.
   NOTAM: …NAV NDB 090-180 BEYOND 15NM UNUSABLE…
6. Glide slope tolerances are exceeded at a specific point on the glidepath. Describe the restriction from the surface to the altitude specified in the flight inspection report. For example, an ILS glide slope is found unusable below 2900FT MSL.

1. An ILS localizer exceeds tolerances at a point prior to the runway. For example, the localizer is unusable from 0.5 NM inbound.
   NOTAM: …NAV ILS RWY 25 LOC UNUSABLE WI .5NM…

1. An ILS localizer is restricted in usable distance. For example, the localizer is restricted beyond 12 NM from the facility.
   NOTAM: …NAV ILS RWY 33 LOC UNUSABLE BEYOND 12NM…
2. A Cat II ILS ceases to meet CAT II criteria. Flight Inspection will coordinate with AIS to issue an FDC NOTAM to show “CAT II NA” for the associated ILS approach procedure.
3. A CAT III ILS localizer exceeds CAT III tolerances in Zone 4. Flight Inspection will coordinate with AIS to issue an FDC NOTAM to show “CAT III NA” for the associated ILS approach procedure.
4. A CAT II ILS localizer exceeds tolerances in Zone 4, (Zone 4 is not required for CAT II performance level II/T). A facility NOTAM (NOTAM D) is issued.
   NOTAM: …NAV ILS RWY 28 UNUSABLE INSIDE RWY THR...
5. A CAT III ILS localizer exceeds tolerances in Zone 5, (Zone 5 is not required for CAT III performance level III/D). A facility NOTAM (NOTAM D) is issued.
   NOTAM: …NAV ILS RWY 10 UNUSABLE FOR ROLLOUT GUIDANCE…
6. Glide slope does not meet change/reversal tolerances below a point on the glide path. For example, flight inspection determines the glide slope is not suitable for autopilot use below 1574FT MSL. Flight Inspection will coordinate with AIS to issue an FDC NOTAM with the following: AUTOPILOT COUPLED APPROACH NA BELOW 1574FT.

1. Localizer does not meet tolerances in the vertical plane.
   NOTAM: …NAV ILS RWY 22 LOC UNUSABLE BEYOND OM ABOVE 3500FT, AND AT THR ABOVE 500FT...
2. An out-of-tolerance condition is determined for an ILS glide slope left or right of the localizer centerline. For example, flight inspection finds that beyond 5° left of LOC course, there are no glide slope clearances above path, and a glide path is not provided.
   NOTAM: …NAV ILS RWY 30 GP UNUSABLE BEYOND 5DEG LEFT OF COURSE...
3. VGSI systems can have different conditions.

1. A PAPI could be off the air for any reason and the NOTAM would read: U/S. But, if it was found Unsatisfactory by flight inspection, the NOTAM term “UNUSABLE” is more appropriate.
2. When a PAPI is not visible out to the standard 10-degree lateral azimuth due to baffling or optical performance, the NOTAM should describe the unusable area referenced to the runway centerline.
   For example, the PAPI is not visible beyond 6 degrees left of centerline.
   NOTAM: …RWY 18 PAPI BEYOND 6DEG LEFT OF RCL UNUSABLE...
3. VGSI may also be restricted in usable distance for obstacle clearance.
   For example, the obstacle clearance plane is penetrated at some distance.
   NOTAM: …RWY 32 PAPI BEYOND 2.8NM UNUSABLE...

1. SATELLITE BASED SYSTEMS

See Appendix A for examples.

1. Global Positioning System (GPS). Candidate global positioning system pseudo-random noise (PRN) GPS satellite outages will be reported directly to the USNOF (must be properly formatted) by the Air Force Space Command (AFSPACECOM) monitoring facility. The USNOF will issue NOTAMs under the accountability “GPS” with a location of “GPS.” When these NOTAMs get distributed internationally, the NOTAM System changes the designator “KNMH.” (Refer to 1-2-1a.)

1. Wide Area Augmentation System (WAAS). WAAS area-wide NOTAMs are originated when WAAS assets are out of service and impact the service area. The term “MAY NOT BE AVBL” indicates that due to ionospheric conditions, lateral guidance may still be available when vertical guidance is unavailable. Under certain conditions, both lateral and vertical guidance may be unavailable. The USNOF distributes these as FDC NOTAMs when a WAAS asset failure affects a large area. USNOF utilizes templates provided by Technical Operations, WAAS Operations. All events must reflect an effective time and expiration time.

1. Unscheduled loss of signal or service.
2. Ionosphere storm conditions.
3. Scheduled loss of signal or service.
4. Operating under a single GEO
5. Extreme storm detector trips
6. Test
7. Emergency

1. Automatic Dependent Surveillance-Broadcast (ADS-B) and Wide-Area Multilateration (WAM). ADS-B and WAM NOTAMs are originated when assets are out of service and impact the service area. USNOF distributes these as FDC NOTAMs and utilizes templates provided by Technical Operations. All events must reflect an effective time and expiration time, whether scheduled or unscheduled loss of signal or service.

1. ADS-B. Distributed as FDC NOTAMs.
2. WAM. Issued as NOTAM D, with the impacted airport as the affected location.

1. Service Availability Prediction Tool (SAPT). If SAPT is out of service, then operators are entitled to relief from the preflight check requirements and will not be penalized. Otherwise, operators may use the FAA-provided preflight SAPT to determine predicted navigation or surveillance availability before a flight. SAPT predictions are based on:

1. The time, route, and airspace of the planned flight;
2. The announced status of the Global Positioning System (GPS) satellite constellation; and
3. ADS-B related avionics on the subject aircraft.

1. Ground Based Augmentation System (GBAS) and GBAS Landing System (GLS). Originate NOTAMs when the GBAS is unserviceable, is predicted to be unserviceable, or the usability of the GLS is restricted. GBAS facilities are operated by non-federal service providers.

1. Unscheduled loss of signal or service.
2. Predicted loss of signal or service.
3. Restricted usability of GLS.

1. HOURS OF OPERATION

Changes in the hours of operation of a NAVAID due to other than seasonal daylight time changes.