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FAQ
Last updated: March 12, 2026
This page addresses common questions about PERTI from various user perspectives.
PERTI (Plan, Execute, Review, Train, and Improve) is a web-based traffic flow management platform designed for VATSIM. It provides tools for virtual air traffic controllers to manage traffic flow, monitor incidents, coordinate operations, and analyze demand.
PERTI is designed for multiple audiences within VATSIM:
- National TMU Personnel - Traffic management initiatives and planning
- Facility TMU - Local traffic management and coordination
- ATC Personnel - Situational awareness and coordination
- Division/Facility Management - Oversight and planning
- Virtual Special Operations - Military and special mission coordination
- Virtual Airline Operators - Flight planning and delay information
- VATSIM Supervisors - Network oversight
Yes. PERTI is provided as a service to the VATSIM community. The source code is available under the MIT License.
For viewing public pages (JATOC, NOD), no account is required. For authenticated features (GDT, Route Plotter, Planning tools), you must log in with your VATSIM account.
- Navigate to https://perti.vatcscc.org
- Click "Login" or access any authenticated page
- You will be redirected to VATSIM Connect
- Authorize PERTI to access your VATSIM account
- You will be returned to PERTI, logged in
Basic access requires only VATSIM authentication. Additional roles (DCC, TMU) are assigned by administrators for traffic management functions.
Editing capabilities for TMIs, incidents, and advisories require DCC role assignment. Contact the vATCSCC administration if you believe you should have elevated access.
Sessions expire after 24 hours of inactivity. Simply log in again via VATSIM Connect.
A Ground Stop (GS) holds all departures to a specific airport. In PERTI, you can:
- Create a proposed GS
- Model affected flights
- Activate the GS (issue EDCTs)
- Extend or purge as conditions change
A Ground Delay Program (GDP) assigns Expect Departure Clearance Times (EDCTs) to flights when arrival demand exceeds capacity. Unlike a Ground Stop, flights still depart but at controlled intervals.
PERTI calculates demand based on:
- Filed flight plans to an airport
- ETA calculations from current positions
- Historical data from similar events
- Weather conditions affecting capacity
The system suggests appropriate acceptance rates (AAR/ADR) based on current conditions.
Ground Stops use tiers to define affected traffic:
- Tier 1: Flights within a certain distance/time
- Tier 2: Extended scope
- Tier 3: All flights to the destination
- ATC Zero - Complete suspension of ATC services
- ATC Alert - Degraded services with significant impact
- ATC Limited - Reduced capacity or services
- Non-Responsive - Communication issues
| Level | Description |
|---|---|
| 1 | Normal operations |
| 2 | Degraded operations |
| 3 | Severely impacted operations |
Viewing is public. Creating and updating incidents requires DCC role authorization.
- Active Traffic Management Initiatives with rich data cards:
- GS cards: countdown timer, flights held, prob extension, origin centers
- GDP cards: controlled/exempt counts, avg/max delay, compliance bar, GDT link
- Reroute cards: assigned/compliant counts, compliance bar
- MIT/AFP: restriction details and fix coordinates
- Delay Reports: severity coloring and trend indicators
- Map TMI status layer: airport rings by severity, delay glow circles, MIT fix markers
- Facility flow configurations with FEA demand integration
- DCC Advisories
- Current operations status
- Weather impacts
Facility Flow Configurations define traffic flow patterns for ATC facilities. Each config contains:
- Elements: Fixes, procedures, routes, and gates that define a flow pattern
- Visual controls: Color, line weight, visibility toggles per element
- FEA Integration: Elements can be linked to Flow Evaluation Areas for demand monitoring
- Map layers: 8 layer types including boundaries, procedure/route lines, fix markers
Flows are managed in the Flows tab of the NOD sidebar, with per-facility and per-config selectors.
NOD data refreshes automatically every 30 seconds for active TMIs and every minute for other data.
- Access Route Plotter at
/route.php - Enter origin and destination airports
- Enter route string (optional)
- Click "Plot" to display on map
Public routes are shared route advisories visible to all users. They can be used for coordination during weather events or special operations.
The weather radar displays NEXRAD/MRMS data from the Iowa Environmental Mesonet. This is real-world radar data, not VATSIM simulation weather.
A Traffic Management Review (TMR) report is a structured post-event analysis following the NTMO Guide format. It includes sections for:
- Triggers - What initiated the review
- Overview - Event summary
- Airport Conditions - Configuration, rates, weather
- Weather - Weather impacts and forecasts
- TMIs - Traffic management initiatives applied (with historical TMI lookup and bulk NTML paste parser)
- Equipment - System/equipment issues
- Personnel - Staffing considerations
- Findings - Conclusions and recommendations
Navigate to the Review page and select "Create TMR Report" for an existing plan. The report auto-saves as you work, and can be exported in Discord format for sharing.
TMR reports include per-airport demand charts (DemandChartCore) that visualize arrival/departure demand during the event period.
The Playbook is a pre-coordinated route play catalog for traffic management. It stores collections of routes organized by scenario (weather, volume, construction) that can be quickly activated during events.
Plays originate from four sources:
- FAA — Imported from national playbook data
- DCC — Custom plays authored by the Command Center
- ECFMP — EUROCONTROL-style flow measures from European divisions
- CANOC — Canadian Network Operations Centre plays
Yes. Use shareable links: https://perti.vatcscc.org/playbook.php?play=PLAY_NAME. When loaded, the page auto-selects and displays the referenced play.
Use the Bulk Paste feature in the edit modal. Paste ECFMP or CANOC format route text, and the parser automatically structures the routes and detects the source format.
See Playbook for full documentation.
Splits define how an ARTCC's airspace is divided into sectors. Each configuration assigns positions to sector areas and can be activated for events or scheduled to auto-activate at specific times.
Strata filtering lets you view sectors by altitude stratum: low (surface to FL230), high (FL230 to FL370), or superhigh (FL370+). This is controlled via checkboxes on the splits map.
23 US ARTCCs and 7 Canadian FIRs (CZYZ, CZWG, CZEG, CZUL, CZVR, CZQM, CZQX) with 1,379 total sector boundaries. Additional international FIRs (Mexico, Caribbean) are supported but may have limited sector data.
Yes. Scheduled splits have start/end times (UTC) and are automatically activated/deactivated by the scheduler_daemon.php.
See Splits for full documentation.
Hibernation mode is a cost-saving operational state that suspends most processing daemons, redirects web pages to /hibernation, and downscales Azure resources. Only the core ADL ingest daemon continues running during hibernation, maintaining basic flight data ingestion. Monthly infrastructure costs drop from approximately $3,500 to $150-170. Enter and exit procedures are documented in docs/HIBERNATION_RUNBOOK.md.
As of March 2026, PERTI has processed:
- 1.6M+ flights tracked
- 9.3M+ waypoints extracted from flight plans
- 20.5M+ boundary crossings predicted
- 269K navigation fixes in reference data
- 27K+ airports worldwide
- 10K+ DPs/STARs (departure/arrival procedures)
- 41K+ Coded Departure Routes (CDRs)
- 56K+ playbook routes
PERTI uses a CASA-FPFS + RBD hybrid algorithm for Ground Delay Programs. CASA (Compression After Slot Assignment) assigns slots first, then compresses to minimize total delay. FPFS (First Planned First Served) allocates slots based on original estimated arrival time. RBD (Ration By Distance) distributes delay proportionally based on flight distance from the destination.
The algorithm was redesigned in four phases:
-
Phase 1 -- Bug fixes,
compress.phpendpoint, batch optimization - Phase 2 -- FPFS+RBD algorithm implementation, adaptive reserves, FlightListType TVP rebuild
-
Phase 3 --
sp_TMI_ReoptimizeProgramorchestrator,reoptimize.phpendpoint - Phase 4 -- Reversal metrics, anti-gaming flags, GDT UI observability (compress/reopt controls)
The automatic daemon reoptimization cycle (2-5 minute intervals) is pending implementation post-hibernation.
Adaptive Compression (ADPT) automatically moves flights up to fill slots that would otherwise be wasted (e.g., when a flight cancels or substitutes). It helps maximize efficiency during GDPs and AFPs.
PERTI has a full i18n infrastructure with 7,276 translation keys in en-US.json. Supported locales: en-US (full), fr-CA (near-complete with 7,560 keys), en-CA (overlay), en-EU (overlay). Overlay locales inherit from en-US and only override specific keys (e.g., terminology differences). Currently, 45 of 65 JS modules (69%) use the i18n system, and all 30 PHP pages auto-include the i18n system via load/header.php.
- URL parameter (
?locale=en-US) - localStorage (
PERTI_LOCALE) - Browser language (
navigator.language) - Fallback:
en-US
PERTI supports modern browsers:
- Chrome 90+
- Firefox 88+
- Safari 14+
- Edge 90+
Internet Explorer is not supported.
PERTI receives data from VATSIM approximately every 15 seconds. Processing adds minimal latency. Total delay from real-time is typically 15-30 seconds.
Yes. See API Reference for available endpoints. Most endpoints require authentication.
PERTI runs on Microsoft Azure App Service (P1v2) with 7 databases across 3 engines:
- Azure SQL (vatsim.database.windows.net): VATSIM_ADL (Hyperscale Serverless), VATSIM_TMI, SWIM_API, VATSIM_REF, VATSIM_STATS
- MySQL (vatcscc-perti.mysql.database.azure.com): perti_site (General Purpose D2ds_v4)
- PostgreSQL/PostGIS (vatcscc-gis.postgres.database.azure.com): vatcscc_gis (Burstable B2s)
Total infrastructure cost is approximately $3,500/month. See the transparency page for details.
- VATSIM CID (from OAuth login)
- Name (from VATSIM profile)
- Session data (temporary)
- No additional personal information is collected
- Current flight state: Updated every 15 seconds
- Historical snapshots: Retained for 30 days
- Trajectory data: Retained for 7 days
Flight data visible in PERTI is derived from VATSIM's public data feed. No additional personal data is shared with third parties.
- Check your internet connection
- Try refreshing the page
- Clear browser cache
- Try a different browser
- Ensure JavaScript is enabled
- Check browser console for errors
- Try disabling browser extensions
- Verify WebGL is supported
- Verify VATSIM Connect is operational
- Clear cookies and try again
- Try incognito/private browsing mode
- Contact support if issue persists
- Refresh the page
- Check VATSIM API status
- Data may lag up to 30 seconds during high traffic
Report bugs on GitHub Issues with:
- Description of the issue
- Steps to reproduce
- Expected behavior
- Screenshots if applicable
Open a GitHub Issue with the "feature request" label, describing:
- The feature you'd like
- The problem it solves
- Your use case
PERTI is maintained by the vATCSCC development team. For operational questions, contact division administration.
This is a quick reference. For comprehensive acronym definitions, see Acronyms.
| Term | Definition |
|---|---|
| AAR | Airport Arrival Rate - maximum arrivals per hour |
| ADL | Aggregate Demand List - flight data feed from TFMS containing schedules and NAS information |
| ADR | Airport Departure Rate - maximum departures per hour |
| AFP | Airspace Flow Program - controls departure times for flights to an FCA |
| ARTA/ARTD | Actual Runway Time of Arrival/Departure (formerly AGTA/AGTD) |
| ARTCC | Air Route Traffic Control Center |
| CTA/CTD | Controlled Time of Arrival/Departure |
| DCC | Command Center |
| EDCT | Expect Departure Clearance Time |
| ETA/ETD | Estimated Time of Arrival/Departure |
| FCA | Flow Constrained Area - airspace element used with AFPs |
| FSM | Flight Schedule Monitor |
| GDP | Ground Delay Program |
| GS | Ground Stop |
| JATOC | Joint Air Traffic Operations Command |
| NOD | NAS Operations Dashboard |
| OOOI | Out-Off-On-In (flight phase tracking) |
| ORTA/ORTD | Original Runway Time of Arrival/Departure (formerly OGTA/OGTD) |
| SUA | Special Use Airspace |
| TFMS | Traffic Flow Management System |
| TFR | Temporary Flight Restriction |
| TMI | Traffic Management Initiative |
| TMU | Traffic Management Unit |
| TSD | Traffic Situation Display |
- Getting Started - Setup guide
- Acronyms - Complete acronym reference
- API Reference - API documentation
- Troubleshooting - Detailed troubleshooting guide
PERTI - Virtual Air Traffic Control System Command Center Production Site | GitHub | Report Issue
Last updated: 2026-02-25
Home Navigation Helper (NEW)
Comprehensive Guides
Getting Started
Architecture
Algorithms & Processing
- Algorithms Overview
- Algorithm ETA Calculation
- Algorithm Trajectory Tiering
- Algorithm Zone Detection
- Algorithm Route Parsing
- Algorithm Data Refresh
SWIM API (Public/External)
- SWIM API
- SWIM Routes API
- SWIM Playbook API
- SWIM Route Data Integration
- Building Route Processing
- CDM Connector Guide
PERTI API (Internal)
Features
Walkthroughs
Operations
Development
Analysis
- Analysis (index)
- ETA Accuracy (Jan-Mar 2026)
Reference