Section 3. NAVAID NOTAMs
Known or reported malfunctions of a navigational aid must be reported to Technical Operations or appropriate personnel.
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.
- Routine maintenance shutdown. When possible, approval should be obtained sufficiently in advance of the proposed shutdown time to allow dissemination of a 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 5 hours in advance of the shutdown.
- Emergency shutdown. When possible, obtain at least 1-hour advance notice so that appropriate dissemination may be made before shutdown.
- 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 no more than 7 days before the shutdown.
- All VOR, VORTAC, and equipment in the have automatic monitoring and shutdown features in the event of malfunction.
- 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 placing the aid in an unmonitored status.
- When issuing a describing a facility as unmonitored, do not use the category of monitor, only the phrase “NOT MNT.”
- Do not issue a for a standalone that is not monitored.
- If the NAVAID is reported as being unserviceable, the unmonitored must be canceled.
- Technical Operations issue s related to outages or restrictions for all equipment and components that they own/maintain/certify, regardless of duration. 24/7 Center is responsible for issuing any procedural s, such as flight data center (FDC) s. Consult FAA Order 6750.24 to determine if any additional Ds should be issued. Ideally, a will allow authorized operators to continue, while notifying unauthorized operators that the specified approach procedure is not available. It is critical that required s 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.
- 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 request for loss of category will be made if the equipment failures warrant this action.
- When Technical Operations personnel issue a suspending CAT II/III minimums, must be notified. If the suspension will exist longer than 224-days or is permanent, must submit a full or abbreviated procedure amendment prior to the 224-day suspense.
- Special Authorization CAT I/II approaches. These Part 97 CAT I/II approaches are identified as “ RWY XX (SA CAT I) or RWY XX (SA CAT II)” and by an additional chart note saying “Reduced Lighting: Requires specific OpSpec, MSpec, or LOA approval.”
- The aircraft operator is authorized to conduct CAT I/II IAP on certain facilities that do not meet the equipment requirements of a U.S. Standard or 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.
- 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.
…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.
- Introduction. Facility status classification and (s) will indicate restriction(s) to the expected use of these facilities. The 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.
Facility Status Classification.
Operational Status. The legal facility status of Usable or Unusable is broken down as follows:
- Usable. The facility is available for operational use and is either.
- Unrestricted. Providing safe, accurate signals-in-space conforming to established standards within the coverage area of the facility.
- 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.
- 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.
- General. Originate a D for commissioning, decommissioning, outages, or unmonitored status of radio navigation aids (60 minutes or more) that are part of the . The must be cancelled by the originator. An exception is that Technical Operations will originate a for all Instrument Landing System Equipment and components for all associated outages regardless of duration. When a flight inspection necessitates action, the flight inspector is responsible for initiating the (s). The flight inspector must verify within 24 hours that the appropriate (s) were issued, amended, or cancelled. The inspector must verify that (s) are published in the appropriate agency publication.
- Facility D. The inspector must immediately initiate action whenever a facility restriction is found or revised.
- Initiating FDC NOTAM(s). FDC NOTAM(s) must be issued if a restriction affects instrument flight procedures, approach minimums, or category () 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 () to ensure FDC NOTAM(s) resulting from reported facility outages, flight inspection results, or restriction changes are issued. The NOCC automatically notifies the when there is a facility outage or restoration. The OKC SC will notify when a flight inspection results in a new or canceled facility restriction.
- 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.
- Preparation of (s).
- (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 .
- Restrictions to VORTAC and facilities are issued via D, including azimuth restrictions. The preparation for the azimuth component of a VORTAC is identical to the VOR.
- Facility Restrictions. Restrictions to NAVAIDs are normally published by segment: for example, 020-055 degree radials. To correct a given segment, cancel the original and issue a completely new . 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.
- 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 (s) will use the “SFC-XXXXFT” format. For example: a VOR found unusable below 3000FT MSL would result in a that lists the restriction as unusable “SFC-2900FT.” Use a 100FT increment from the “usable” altitude to describe the first “unusable” altitude.
- 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 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 . Technical Operations and Aeronautical Information Services Office make the determination when to issue an FDC NOTAM or D, based on FAA JO 6750.49, Maintenance of Instrument Landing System () Facilities. Tech Ops issues the D and 24/7 Center issues the FDC.
- VOR/ // / / 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.”
- When describing restrictions to these kind of facilities:
- Describe the radials or bearings that are unusable.
- Describe the mileage point beyond which the facility is unusable.
- Describe any altitude restriction using the format.
- Follow this guidance for identifying specific components:
- VOR/. Reference “VOR/” when the restriction simultaneously applies to both the VOR and performance. Just use “VOR” if the restriction only applies to the VOR component, and “” if it only applies to the component.
- VORTAC. Reference “VORTAC” when all components (VOR, TACAN AZM, and ) are being restricted together. Reference the individual component if the restriction only applies to that component.
- (VOR Test Facility).
- VOR Receiver Checkpoint. There are airborne receiver checkpoints (VOR AIRBORNE REC CHECKPOINT) and ground receiver checkpoints (VOR GND REC CHECKPOINT).
If there is more than one ground checkpoint, describe the location also.
- s serving one airport, and not associated with airway structure, must have s issued using the associated airport identifier as the affected facility.
- s serving more than one airport, or associated with airway structure, must have s issued using the identifier as the affected facility.
- Terminal s. Those s located on or serving only that airport must have s issued using the associated airport as the affected facility.
- If an serves more than one airport, or associated with an airway route structure, issue a using the identifier of the as the affected facility.
- LOM outages.
- LOM serving one airport must be issued with the three-letter identifier of the airport as the location identifier.
- 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.
- NAVAID identification change. (See example in Appendix A).
- 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.
- A DME can be a separate facility, or a facility associated with an , LOC, LOC Type Directional Aid, Simplified Direction Finder, and VOR. When a is a separate system (a -only facility), the only condition is unserviceable. Restrictions are not published for -only facilities.
- Instrument Landing Systems ().
…NAV ILS RWY 12 LOC UNUSABLE BEYOND 4DEG RIGHT OF COURSE…
- Distinguish components of an from non-precision approach NAVAIDs by preceding the component with “” followed by “RWY” and the runway number (including single airports). Use the term “COURSE” when describing radio navigation aid restrictions. Coupled approach restrictions (for CAT I) are issued via FDC NOTAM.
…NAV ILS RWY 14 LOC U/S…
- 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.
…NAV LOC RWY 16 BC UNUSABLE BEYOND 6DEG RIGHT OF COURSE…
…NAV LOC RWY 05 BC U/S…
- Restrictions on instrument flight procedures caused by outages to a localizer backcourse will be issued separately as FDC NOTAMs.
- When describing the back course, the runway designator is for the back course approach runway.
- 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 distances may be used if the is part of the approach procedure.
- 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 .
…NAV LOC RWY 08 U/S…
…NAV LOC RWY 08 UNUSABLE BEYOND 6DEG RIGHT OF COURSE…
- Lateral Restriction: Lateral restrictions are measured in degrees left or right of inbound course.
- 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.
- 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.
Additional reference to distances may be used for ease of correlating the restriction distance to the approach procedure, for those approach procedures with . However, distance will not be used to replace the distance from threshold/antenna.
Modifying an existing facility . 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 indicates that all other restrictions have been canceled.
Flight Inspection Work Flow Process:
Given a VOR/ with the published (not s) restrictions of:
VOR Unusable: 005-040 BEYOND 27NM SFC-13000FT
VOR Unusable: 325-040 BEYOND 20NM SFC-10500FT
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.
Next, issue the with the new restriction with the addition of “PLUS SEE”:
…VOR 005-040 BEYOND 25NM SFC-13900FT UNUSABLE PLUS SEE CHART SUPPLEMENT…
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 course structure and unusable .
: …NAV VORTAC 025-075 BEYOND 25NM SFC-3400FT UNUSABLE…
The VOR and 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 is unaffected. Issue separate s for each component.
: …NAV VOR 025-075 BEYOND 25NM SFC-3400FT UNUSABLE...
: …NAV TACAN AZM 025-075 BEYOND 25NM SFC-3400FT UNUSABLE…
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.
: …NAV VOR 080-100 BEYOND 18NM SFC-3400FT, 101-200 BEYOND 30NM SFC-4400FT UNUSABLE…
A VOR is unusable in various areas below one altitude, and the 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. unusable 225° CW 275° in the following areas: Beyond 15 NM below 2,400FT MSL and beyond 30 NM below 5,000FT MSL.
: …NAV VOR 250-265 BEYOND 17NM, 266-280 BEYOND 10NM, 281-290 BEYOND 17NM SFC-1600FT UNUSABLE…
: …NAV DME 225-275 BEYOND 15NM SFC-2300FT UNUSABLE…
: …NAV DME 225-275 BEYOND 30NM SFC-4900FT UNUSABLE…
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.
: …NAV NDB 090-180 BEYOND 15NM UNUSABLE…
- 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 glide slope is found unusable below 2900FT MSL.
An localizer exceeds tolerances at a point prior to the runway. For example, the localizer is unusable from 0.5 NM inbound.
: …NAV ILS RWY 25 LOC UNUSABLE WI .5NM…
(WI = within)
An localizer is restricted in usable distance. For example, the localizer is restricted beyond 12 NM from the facility.
: …NAV ILS RWY 33 LOC UNUSABLE BEYOND 12NM…
- A Cat II ILS ceases to meet CAT II criteria. Flight Inspection will coordinate with to issue an FDC NOTAM to show “CAT II NA” for the associated approach procedure.
- A CAT III ILS localizer exceeds CAT III tolerances in Zone 4. Flight Inspection will coordinate with to issue an FDC NOTAM to show “CAT III NA” for the associated approach procedure.
A CAT II ILS localizer exceeds tolerances in Zone 4, (Zone 4 is not required for CAT II performance level II/T). A facility ( D) is issued.
: …NAV ILS RWY 28 UNUSABLE INSIDE RWY THR...
A CAT III ILS localizer exceeds tolerances in Zone 5, (Zone 5 is not required for CAT III performance level III/D). A facility ( D) is issued.
: …NAV ILS RWY 10 UNUSABLE FOR ROLLOUT GUIDANCE…
- 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 to issue an FDC NOTAM with the following: AUTOPILOT COUPLED APPROACH NA BELOW 1574FT.
The facility is not considered restricted.
Localizer does not meet tolerances in the vertical plane.
: …NAV ILS RWY 22 LOC UNUSABLE BEYOND OM ABOVE 3500FT, AND AT THR ABOVE 500FT...
An out-of-tolerance condition is determined for an 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.
: …NAV ILS RWY 30 GP UNUSABLE BEYOND 5DEG LEFT OF COURSE...
- VGSI systems can have different conditions.
- A PAPI could be off the air for any reason and the would read: U/S. But, if it was found Unsatisfactory by flight inspection, the term “UNUSABLE” is more appropriate.
When a PAPI is not visible out to the standard 10-degree lateral azimuth due to baffling or optical performance, the should describe the unusable area referenced to the runway centerline.
For example, the PAPI is not visible beyond 6 degrees left of centerline.
: …RWY 18 PAPI BEYOND 6DEG LEFT OF RCL UNUSABLE...
VGSI may also be restricted in usable distance for obstacle clearance.
For example, the obstacle clearance plane is penetrated at some distance.
: …RWY 32 PAPI BEYOND 2.8NM UNUSABLE...
See Appendix A for examples.
- Global Positioning System (). Candidate global positioning system pseudo-random noise (PRN) 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 s under the accountability “” with a location of “.” When these s get distributed internationally, the System changes the designator “KNMH.” (Refer to 1-2-1a.)
operations are included in the Aeronautical Information Manual.
Candidate testing s must be properly formatted when received from Technical Operations ATC Spectrum Engineering Services, Spectrum Assignment and Engineering Services. The USNOF will issue s under the accountability “” with a location identifier of the associated center.
- Wide Area Augmentation System (). area-wide s are originated when 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 asset failure affects a large area. USNOF utilizes templates provided by Technical Operations, Operations. All events must reflect an effective time and expiration time.
- Unscheduled loss of signal or service.
- Ionosphere storm conditions.
- Scheduled loss of signal or service.
- Operating under a single GEO
- Extreme storm detector trips
- Automatic Dependent Surveillance-Broadcast () and Wide-Area Multilateration (WAM). 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.
- . Distributed as FDC NOTAMs.
- WAM. Issued as NOTAM D, with the impacted airport as the affected location.
- 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:
- The time, route, and airspace of the planned flight;
- The announced status of the Global Positioning System () satellite constellation; and
- related avionics on the subject aircraft.
Under 14 CFR § 91.103, pilots and operators must use all available information in planning their flight to ensure that they will meet the performance requirements for the duration of the flight.
- Ground Based Augmentation System (GBAS) and GBAS Landing System (GLS). Originate s 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.
- Unscheduled loss of signal or service.
- Predicted loss of signal or service.
- Restricted usability of GLS.
Changes in the hours of operation of a NAVAID due to other than seasonal daylight time changes.