JO 7110.65 — Air Traffic Control
JO 7110.65 3-3-7
FAR FIELD MONITOR (FFM) REMOTE STATUS UNIT
To meet the demand for more facilities capable of operating under CAT III weather, Type II equipment is being upgraded to Integrity Level 3. This integrity level will support operations which place a high degree of reliance on ILS guidance for positioning through touchdown.
Installation of the FFM remote status indicating units is necessary to attain the integrity necessary to meet internationally agreed upon reliability values in support of CAT III operations on Type II ILS equipment. The remote status indicating unit used in conjunction with Type II equipment adds a third integrity test; thereby, producing an approach aid which has integrity capable of providing Level 3 service.
The remote status sensing unit, when installed in the tower cab, will give immediate indications of localizer out‐of‐tolerance conditions. The alarm in the FFM remote status sensing unit indicates an inoperative or an out‐of‐tolerance localizer signal; e.g., the course may have shifted due to equipment malfunction or vehicle/aircraft encroachment into the critical area.
Operation of the FFM remote sensing unit will be based on the prevailing weather. The FFM remote sensing unit must be operational when the weather is below CAT II ILS minimums. REFERENCE-
FAA Order 6750.24, Appendix A, Abnormal Checklist
When the remote status unit indicates that the localizer FFM is in alarm (aural warning following the preset delay) and: The aircraft is outside the middle marker (MM) or in the absence of a MM, ½ mile final, check for encroachment of those portions of the critical area that can be seen from the tower. It is understood that the entire critical area may not be visible due to low ceilings and poor visibility. The check is strictly to determine possible causal factors for the out-of-tolerance situation. If the alarm has not cleared prior to the aircraft's arriving at the MM or in the absence of a MM, ½ mile final, immediately issue an advisory that the FFM remote status sensing unit indicates the localizer is unreliable.
The aircraft is between the MM or ½ mile final and the inner marker (IM), or if the IM is not installed, the CAT II Missed Approach Point (MAP), immediately issue an advisory that the FFM remote status sensing unit indicates the localizer is unreliable. PHRASEOLOGY-
CAUTION, MONITOR INDICATES RUNWAY (number) LOCALIZER UNRELIABLE.
The aircraft has passed the IM or the CAT II MAP (if the IM is not installed) there is no action requirement. Although the FFM has been modified with filters which dampen the effect of false alarms, you may expect alarms when aircraft are located between the FFM and the localizer antenna either on landing or on takeoff. REFERENCE-
FAA Order JO 7110.65, Para 4-7-12 , Airport Conditions.
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Chapter 3. Airport Traffic Control - Terminal 7110.65BB
7110.65 by Chapter Number Chapter 0. General Information Chapter 1. General Chapter 2. General Control Chapter 3. Airport Traffic Control - Terminal Chapter 4. IFR Chapter 5. Radar Chapter 6. Nonradar Chapter 7. Visual Chapter 8. Offshore/Oceanic Procedures Chapter 9. Special Flights Chapter 10. Emergencies Chapter 11. Traffic Management Procedures Chapter 12. Canadian Airspace Procedures Chapter 13. Decision Support Tools Chapter 14. Data Link Communications Appendix A Appendix B
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JO 7110.65BB by Topic
General Information Explanation of Changes
General Introduction
Terms of Reference
General Control General
Flight Plans and Control Information
Flight Progress Strips
Radio and Interphone Communications
Route and NAVAID Description
Weather Information
Altimeter Settings
Runway Visibility Reporting- Terminal
Automatic Terminal Information Service Procedures
Team Position Responsibilities
Airport Traffic Control - Terminal General
Visual Signals
Airport Conditions
Airport Lighting
Runway Selection
Airport Surface Detection Procedures
Taxi and Ground Movement Procedures
Spacing and Sequencing
Departure Procedures and Separation
Arrival Procedures and Separation
Helicopter Operations
Sea Lane Operations
IFR NAVAID Use Limitations
Clearances
Departure Procedures
Route Assignment
Altitude Assignment and Verification
Holding Aircraft
Arrival Procedures
Approach Clearance Procedures
Radar General
Beacon/ADS-B Systems
Radar Identification
Transfer of Radar Identification
Radar Separation
Vectoring
Speed Adjustment
Radar Departures
Radar Arrivals
Radar Approaches- Terminal
Surveillance Approaches- Terminal
PAR Approaches- Terminal
Automation- En Route
Standard Terminal Automation Replacement System (STARS)-Terminal
Nonradar General
Initial Separation of Successive Departing Aircraft
Initial Separation of Departing and Arriving Aircraft
Longitudinal Separation
Lateral Separation
Vertical Separation
Timed Approaches
Visual General
Visual Separation
VFR‐On‐Top
Approaches
Special VFR (SVFR)
Basic Radar Service to VFR Aircraft- Terminal
Terminal Radar Service Area (TRSA)-Terminal
Class C Service- Terminal
Class B Service Area- Terminal
Offshore/Oceanic Procedures General
Coordination
Longitudinal Separation
Lateral Separation
Offshore/Oceanic Transition Procedures
Separation from Airspace Reservations
North Atlantic ICAO Region
Caribbean ICAO Region
Pacific ICAO Region
North American ICAO Region
Special Flights General
Special Operations
Special Use, ATC-Assigned Airspace, and Stationary ALTRVs
Fuel Dumping
Jettisoning of External Stores
Unmanned Free Balloons
Parachute Operations
Unidentified Anomalous Phenomena (UAP) Reports
Emergencies General
Emergency Assistance
Overdue Aircraft
Control Actions
Miscellaneous Operations
Oceanic Emergency Procedures
Ground Missile Emergencies
Traffic Management Procedures General
Canadian Airspace Procedures General Control
Decision Support Tools ERAM - En Route
ATOP - Oceanic
Data Link Communications Terminal Procedures for Issuing Automated Clearances
En Route Controller Pilot Data Link Communications (CPDLC) - Domestic
Advanced Technologies and Oceanic Procedures (ATOP) - Oceanic Controller Pilot Data Link Communications (CPDLC)
Appendix A
Appendix B
Airport Traffic Control - Terminal
Airport Lighting
Chapter 3. Airport Traffic Control - Terminal
Section 4. Airport Lighting
Retrieved from ecfr.gov on July 20, 2026.