# Presentation: 672677

## Moving toward Arrival-Departure GDP

- Bill Hall
- December 1999

## Why Arrival-Departure GDP?

- Arrivals are only half the story
- Rationing departure resources would
- Provide control over departure delays
- Improve enroute and arrival predictions
- Allow airlines to determine their own tradeoff between delay and cancellation
- Departure queue control
- Reduced fuel use
- Fewer airframe hours
- Less environmental impact

## Careful!

- Time constants much faster on departures
- Substitutions must be nearly instantaneous
- Europe rations arrivals and departures all the time
- This is not the whole answer
- The real motivation --
***Control over arrival - departure interactions***

## Airport Capacity

- Interactions between many factors determine airport capacity
- Airport configuration
- Mixture of arrivals and departures
- Types of aircraft
- To first order, capacity can be represented in arrival-departure space

## The Draper Approach

- Use arrival-departure interactions to everyone’s advantage
- Give users more control
- Require few people in the loop for fast reaction times
- Quantified benefits (from my thesis, May 1999)

## Arrival-departure tradeoff occurs only at a few small airports like BOS and LGA, right?

- For a given configuration, maybe
- But make configuration decisions in concert with demand...

## ORD arrival-departure tradeoff, all configurations

## How ADCAM Achieves Benefit

- During GDPs the FAA currently rations arrival capacity only
- This approach ignores the dynamics of arrival-departure interactions
***ADCAM uses a better airport capacity model that includes arrival-departure interactions***
***ADCAM affords the airlines more control***
- Allows planned operations outside of the box

## Current GDP

## ADCAM GDP

## Allocation to Multiple Users

## Allocation Is Dynamic

- planned operations -- all airlines
- planned United operations
- planned Northwest operations

- United subcapacity
- Northwest subcapacity

- other colors -- other airlines

## Outline of Arrival-Departure Capacity Allocation

- ATCSCC makes arrival-departure capacity forecast
- Arrival-departure capacity rationed by schedule (ADRBS)
- Users employ capacity for arrivals and departures as they see fit
- Arrival-departure compression run

## Progress

- We’ve worked out the details of ADCAM implementation
- We’ve implemented Arrival-Departure Ration By Schedule (ADRBS) in software
- We’ve tested the idea in simulation on optimization-based airline models
- We’ve developed visualizations

## Implications for your Airline

- Control delay / cancellation tradeoff for your own operations
- You own departure resource, use it how you like
- Get extra arrival capacity when you need it
- Preserve bank connection structure
- Get extra departure capacity when you need it
- Ramp / gate congestion
- Freedom to hedge against forecast uncertainty

- cancellations

- depart delay

## Implementation Strategy

- Build support infrastructure
- Incremental benefit along critical path to ADCAM
- Additional improvements as time and funding permit
- Implement Prototype ADCAM
- Start with a demonstration airport
- Needs enough traffic to show benefit
- Pre-operational testing followed by prototype operations
- Extend to entire system

## Path to ADCAM

- Departure
- Demand
- Predictor

- CDM
- Data

- Demand
- Forecast

- Capacity
- Forecast

- Capacity-Based
- Demand Prediction

- Arrival-Departure
- Capacity Modeling

- Configuration
- Planning Tool

- Arrival-Departure
- Op’s Visualization

- GDP What-if
- Calculator

- ADCAM

- critical path

- development begun

- useful tools

**Notes:**
Provide a formal mechanism to use and disseminate arrival-departure capacity forecasts
Elicit arrival-departure capacity forecasts from each airport
Provide arrival-departure capacity forecast to ATCSCC and center
Provide a formal feedback mechanism to improve arrival-departure capacity prediction
Use CDM data to compare the predicted capacity to the traffic counts in periods with queues present
Provide rapid feedback to the staff on duty comparing forecast to realization
Examination of discrepancies in forecast will allow more accurate forecasts to be produced

## What Draper can provide

- ADCAM and simulation tools to analyze ADCAM performance at specific airports
- Prototype Arrival-Departure GDP tools
- Prototype tools for airline decision support under ADCAM
- Support for Prototype Arrival-Departure Operations
- Support for transition to system-wide operations
- Experience analyzing and building real-time systems
- Analytical understanding of ATM and ATFM
- Development to date has been on internal Draper funds
- We’ve invested up the learning curve

## Conclusions

- Arrival capacity depends on departures
- Rationing both gives airlines more control
- Significant flexibility available in the airport “physics” not currently given to the airlines
- Allows better match of demand to capacity
- Possible to reduce airborne holding and ground delays
- Allows better match of ATM strategy to demand
- Better demand information for configuration planning
- Better tactical flow management (MIT, MINIT, vectoring)
- Better en route modeling and allocation

## Draper is ready

- We could start pre-operational testing within a year of authority to proceed
- We have worked out many of the difficult implementation issues
- We’ve developed supporting software
- We’re excited about this and want to be part of CDM
- Involve us to leverage our findings, our progress to date, and our investment