Section 7. Safety Logic Systems Operations Supervisor/CIC Procedures
- Safety logic systems are software enhancements to the ASDE systems (ASDE-3, ASDE-X and ASSC) that predict the path of aircraft landing and/or departing, and/or vehicular movements on runways. Visual and aural alerts are activated when the safety logic projects a potential collision.
- The safety logic system must be operated in a full core alert runway configuration. (In ASDE-X/ASSC, when rain configuration is selected, it includes full core alerting capabilities.)
- In the event of a Multilateration (MLAT) failure, ASDE-X/ASSC will stay operational. In this case, ASDE-X/ASSC will operate in radar-only mode. The system automatically transitions to radar-only mode when it senses an MLAT fault. No action is required by the operator to enable radar-only mode.
- The controller displays will keep maps and track data. Tracks that were currently being tracked when MLAT failed will keep their data blocks while in the coverage area. Tracks on arrival with ASR coverage will also keep a data block while in the coverage area. Tracks moving from a radar-only mode zone to a fully operational zone will display the tracks as it enters the operational zone.
- New tracks will start as unknown icons and must be manually tagged to receive a data block. ASDE-X/ASSC safety logic processing is not affected by radar-only mode operation. The system automatically transitions to normal operation once the MLAT subsystem is back online. Full core alerting capabilities are provided in radar-only mode.
- When ASDE-3 and/or AMASS is in maintenance mode, AMASS data must be considered invalid and the system must be taken offline. The OS/CIC must validate, upon resuming normal AMASS operations, that runway configurations and other user settings are adequate for operational use.
Action to change AMASS online/offline status is a technical operations function. ASDE-X/ASSC safety logic will automatically be disabled when the system is in maintenance mode.
- When a runway becomes unavailable for aircraft operations for an extended period of time, the runway should be entered as “closed” in the safety logic system. Facility procedures should be developed to address using the safety logic system in this capacity.
- Construction projects in the vicinity of runways may cause nuisance or false alerts. It is the responsibility of air traffic facility management to mitigate alerts.
- Air traffic facilities must use the ASDE-X/ASSC “Inhibit Area” map feature to manage construction related alerts when possible.
- National Airway Systems Engineering (NAS Engineering) is able to assist facilities that do not have access to the ASDE-X/ASSC “Inhibit Area” map feature to manage construction related alerts. Facilities must contact NAS Engineering for assistance 30 to 45 days before construction via email at 9-AMC-ATOW-ASDES@faa.gov/.
- Changes to the airport movement areas which require updated ASDE-X/ASSC Maps can be provided by NAS Engineering. Facilities must contact NAS Engineering for assistance 30 to 45 days before construction via email at 9-AMC-ATOW-ASDES@faa.gov/.
- ASDE-X/ASSC false targets may be temporarily track dropped after positive verification has been done by pilot/vehicle operator position report or controller visual observation. When a false target is temporarily dropped, it must be noted on FAA Form 7230-4, Daily Record of Facility Operation.
FAA Order JO 7110.65, Para 3-6-2, Identification.
- The air traffic manager may authorize a real target to be inhibited from safety logic processing when the target will likely generate a nuisance alert.
- The OS/CIC is responsible for ensuring that the Safety Logic System is set for the correct runway configuration.
- The OS/CIC must ensure that the operational status of the Safety Logic System is known to all operational personnel.
- When a status change is made to the Safety Logic System all personnel assigned an operational position must be notified verbally.
- When any status change is made to the Safety Logic System it must be noted on FAA Form 7230-4, Daily Record of Facility Operation. Such status must be shown in the facility Status Information Area (SIA). The OS/CIC must ensure that all outages are carried over on applicable logs.
- The OS/CIC must ensure that the Safety Logic System is monitored and all alerts are complied with.
- All Safety Logic System Alerts generated must be documented on FAA Form 7230-4. If unable to determine the origin of an alert, treat the alert as false and notify Technical Operations so that corrective action can be taken.
Pilot/Controller Glossary Term- Safety Logic System Alerts.
FAA Order JO 7210.632, Chapter 2, Reporting Requirements.
FAA Order JO 7210.632, Appendix A, Mandatory Occurrence Report Criteria.
- Due to the required sensitivity of surface movement radars, numerous false targets may be generated by moderate to extreme precipitation. During these periods the ASDE Safety Logic Systems should be operated in rain configuration. Should precipitation of this magnitude occur or be imminent, rain configuration may be applied to avoid the likelihood of false alerts.
- When the event that led to placing the system into rain configuration is no longer a factor, the Safety Logic System must be reset to a normal configuration.
When AMASS is in rain configuration all safety logic alerts with the exception of arrivals to a closed runway are inhibited and AMASS is not in full core alert status.
- Under certain circumstances, there may be a need to operate the Safety Logic System in limited configuration. The limited configuration must only be used to temporarily inhibit persistent false alerts. The term “persistent false alert” refers to frequent false alerts caused by continuous or repetitive circumstances. False alerts caused by random events or circumstances of short duration are not considered “persistent false alerts.” The determination of “persistent false alerts” is at the discretion of each OS/CIC.
- Due to the required sensitivity of surface movement radars, numerous false targets may be caused by precipitation of moderate or greater intensity. Should precipitation of this magnitude occur or be imminent at locations where ASDE does not have rain configuration availability, limited configuration may be applied to avoid the likelihood of false alerts.
- When it is necessary to operate the ASDE-X/ASSC Safety Logic System in limited configuration due to “persistent false alerts,” notify Technical Operations so that corrective action can be taken.
- When an AMASS false alert is received, limited configuration must only be used until Technical Operations verifies that the system is functioning properly and that the data necessary to analyze the alert has been obtained. Analysis and resolution of the circumstances surrounding the false alert will be determined by Technical Operations at a later date.
- When limited configuration is applied, it must be noted on FAA Form 7230-4, Daily Record of Facility Operation, including the reason for the configuration change. Ensure that all limited configurations are carried over on applicable logs.
- For AMASS, the limited configuration disables all alerts except arrivals to a closed runway and is not considered full-core alert status.
- For ASDE-X/ASSC the limited configuration disables all alerts except arrivals to and departures on a closed runway and is not considered full-core alert status.
The Safety Logic System status must be included in the facility watch checklist. At a minimum, the following items must be reviewed:
- Operational status.
- Runway configuration.
- Presentation of the Safety Logic System data on all ASDE system displays.
- When test button is activated, the aural alert is heard, and the speaker volume is adequate.