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Advanced Technologies & OceaNIC PROCEDURES (ATOP)

John T. Lenhart (ZOA) is the Article 114 Representative for Advanced Technologies & Oceanic Procedures (ATOP).   

ATOP Program  

Background:  The ATOP system processes information consistent with system calculations or expectations (e.g. vertical movement) and provides alerts to controllers when a situation arises or information is received that is out of conformance and/or requires attention or action. This “control by exception” concept has enabled oceanic air traffic operations to advance to a level that would not have been possible under the previous manual system. The ATOP system is anticipated to have the capability and maintainability to meet the future demands posed by new airborne technologies and the associated procedures. 

The ATOP system concept incorporates existing and emerging technologies into a single, integrated system.   

These technologies include:  

  • Flight profile monitoring, utilizing flight data processing and surveillance data processing based on data from the following sources: 

o  Automatic Dependent Surveillance – Broadcast (ADS-B) 

o  Primary and secondary radar 

o  Automatic Dependent Surveillance – Contract (ADS-C FANS-1/A compatible) 

o  Controller-Pilot Data Link Communications (CPDLC) position reports 

o  High Frequency (HF) radio position reports 

  • CPDLC, (FANS-1/A compatible) 
  • Air Traffic Services (ATS)  Inter-Facility Data Communications (AIDC) 
  • NAS Interfacility message set 
  • ATS Facilities Notifications (AFN) (FANS-1/A compatible) 
  • Conflict detection, prediction, and alerting (radar separation and non-radar oceanic separation) 
  • Workload monitor 

The ATOP system manages long-term conflicts (up to two hours), operational requirements (e.g. coordination, workload monitoring), and aircraft requests.   

 The ATOP program consists of an ATOP Program Manager, NATCA National Lead, NATCA Site Leads, and operational area Subject Matter Experts (SME’s) as well as Oceanic Airspace Managers from each Site. We also have representation from AJV-I, AJT, Site Techs, ATOP Second Level Engineering, and ATOP Contract Support.   

Last month the ATOP review focused on the work that was being done in reference to the ATOP T30 build and the concerns over its size and the ability to implement with confidence. The ATOP program and Stakeholders reviewed the T30 content and made the decision to pull three items out of T30 and push them to T31 to mitigate the size and complexity. T30 release date has also moved from Jan. 2022 to June 2022. The items selected to move to T31 and their source lines of code (SLOC) are below: 

ATOP Enhancement 2 (E2) 

*56398 / 59333: Performance Enhancement Improved monitoring capabilities for communication and surveillance network performance: 5124 SLOC 

*58854 NCP: Additional SIM enhancements not covered in 58213: 1440 SLOC 

Oceanic Improvements 

*50981: Submit and disburse CPDLC reported PIREPs: 2520 SLOC 

Oceanic 23NM Lateral Separation Local SRM 

As of Oct. 28Th all three Oceanic Sites have conducted and completed their individual local SRM’s for 23NM Lateral Separation. No additional risks noted at each Site.  

Oceanic 20NM Longitudinal Separation 

20NM Longitudinal requires an updated ADS-C reporting rate of 192 seconds vice the 10 minute contract rate used for 30NM long and also requires a communications performance (RCP) 240, which would be met by use of controller pilot data link (CPDLC). The National SRM is scheduled for Jan. 2021 with a reduced separation WX deviation capability as an assumed environment as a safety mitigation. Both 20 Long and WX deviations have place holders in ATOP T30. ANG-61 (Separation Standards and Analysis) is set to complete the collision risk analysis, including a “know your airspace and equipage” analysis for the SRM panels. Key issue for 20 long is the ability to select the 20 long flag and use immediately while the ADS-C contract is resetting or being required to wait for the ADS-C contract to reset 192 seconds for all involved aircraft prior to issuing clearance. The SRM will be a driver for this requirement. The requirement will drive the completion of the 20 long build.  


This Month the ATOP Program has worked collaboratively with the following Programs/Projects: 

Future of the Ocean 2035 (FOTO 2035) 

FOTO 2035 Program briefed executives this month on its main goals and timeline plan as well as held an Automation/Automation Evolution discussion with various automation stakeholders with the intent to begin the socialization phase.  

Acceptable Level of Risk (ALR) National Lead, Paul Behan 

No Change: The ALR project has went through reorganization. The new direction is to break off into sub groups. Transition Hazard Area’s (THA’s) in the Oceanic environment will include the ATOP program working closely with the ALR team to achieve solutions.  

Spaced Based ADS-B (SBA) National Lead, Dan Hamilton 

The SBA team has now met with all three Oceanic Sites and are in the process of completing the Conops for the SBA Oceanic projects. We are moving ahead under the assumption SBA will meet operational requirements and it is understood that the projects are contingent on that performance. The Team has plans to explore further areas of use in the Oceanic environment.  

As always if anyone would like further discussion on any of the content in this report or anything Oceanic or ATOP related feel free to contact me or the below Site leads and SME’s any time.  

BUR: JT Lenhart ATOP National Lead 


ZNY: John Fox , ZNY Lead, OCA West (WATRS) SME 


         Todd Tourin, North Atlantic SME 


ZAN: Mark Crabtree, ZAN Lead, SME 


ZOA: Donald White, ZOA Lead, Pacific North SME 


         Catherine Siu, ZOA Pacific South SME 


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