Redesigning Air Traffic Control

1
Redesigning Air Traffic Control

• Workshop Session 1
• Airspace, Procedures, and Flight Plans
• September 21, 2000
• Michelle Eshow
• NASA Ames Research Center
• meshow_at_lcs.mit.edu / meshow_at_arc.nasa.gov

2
Outline

• Motivation for ATC RD
• ATC Structure, Facilities
• Airspace
• Controller Roles and Responsibilities
• Delay Causes
• Flight Plans and Route Processing
• Challenges of Automation for ATC

3
Motivation for ATC Automation RD

• ATC system is already beyond its capacity. But
  FAA predicts that by 2010 the number of
  passengers will rise 59, to 1 billion/year.
  Nothing on the drawing board will handle this
  increase. (NY Times, 09/05/00)
• ATC system is very complex and hard to
  understand, analyze, or quantify, which makes it
  interesting!
• Current level of automation is rudimentary
  compared with other systems (eg, aircraft flight
  control systems)
• Application of usable automation to ATC is
  required to meet air travel demands

4
National Airspace System

• Handles 63,000,000 Tower Assisted Operations
• Carries 544,000,000 Passengers
• Over 537,000,000,000 Revenue Passenger Miles
• Using 18,700 Air Carrier A/C
• 170,000 General Aviation A/C
• Supported by 639,000 Pilots
• 651,000 Non-pilots
• Burning 18,000,000,000 Gallons of Fuel
• Generating 87,000,000,000 Revenues
• Producing 5,300,000,000 Profit
• In Spite of 3,500,000,000 in Delays

5
FAA Statistics

• Employs 48,000 People
• Including 17,000 Air Traffic Controllers
• Operating 21 Centers
• 194 TRACONs
• 476 Towers
• 1 Command Center
• Costing 9,200,000,000 Annual Outlay

6
Functions of Air Traffic Management

• Air Traffic Control
• Efficiently manage traffic flow
• Provide flight information (weather, facility)
• Initiate search and rescue operations

Maintain legal separation among aircraft
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ATC Basics

• Airline flights are under positive control at all
  times
• Control is effected by voice via radio
• Control is handed off from one controller/facility
  to another as flight proceeds across boundaries
• controller directs pilot to speak to next
  facility on a different radio frequency
• Communications include
• speed, heading, altitude instructions (vectors)
• notification of other aircraft
• which course or runway to expect
• contact next facility on new frequency

8
ATM Tactical Information Architecture
Host Computer and ATC Information Network
Flight Strips, Flight Information Object
Future Controller
Active Controller
OAG Flight Plan
Voice DAs Procedures
Voice ACARS Flight Plan
Airline Dispatch AOC
Flight Crew
Slide courtesy of Prof. J. Hansman
9
ATC Facilities

• Surface (Ground)
• taxiways
• Local Control (Tower)
• surface to 5 nm out, 2500 ft altitude
• Terminal Area Control/TRACON (Approach or
  Departure)
• to 40 nm from airport, 15K ft altitude
  (inverted wedding cake)
• En-Route Control/ARTCC (Center)
• between, above TRACONs and everything above 18K
  ft
• Flow Control/ATC Systems Command Center
• centralized planning for national flow control
  (does not directly control flights)

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Air Traffic Control System
TMU
TRACON
TRACON
ATCT
ATCT
ARTCC (Center)
11
US Airspace Sector Structure
Slide courtesy of Prof. J. Hansman
12
Air Route Traffic Control Center (ARTCC)
21 ARTCCs 3 CERAPs (combined Center RAPCONs)
A facility established to provide air
traffic control service to aircraft
operating on IFR flight plans within
controlled airspace and principally during
the en route phase of flight. At some
airports not served by an Approach Control
facility, the ARTCC provides limited
approach control service. When equipment
capabilities and controller workload permit,
certain advisory/assistance services may be
provided to VFR aircraft. Air Traffic
Control Manual Order 7110.65
Pilot/Controller Glossary
13
Airspace Orientation
Fort Worth ARTCC
18 Low Altitude Sectors
FL 230 Below
14
Airspace Orientation
Fort Worth ARTCC
15 High Altitude Sectors
FL 240 Above
LBB
MAF
15
Super High Sectors
FL350 and above
High Sectors
FL240 to FL330
Low Sectors
VFR TWR or Uncontrolled
Approach Control
FL230 and below
16
TRACON Video Map
17
TRACON SECTOR DELEGATED AIRSPACE
TRACON Sector Delegated Airspace
18
Special Use Airspace

• Alert Area
• Air Traffic Control Assigned Airspace
• Controlled Firing Area

• Military Operating Area
• Prohibited Area
• Restricted Area
• Warning Area

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Facility Organization
Fort Worth ARTCC
7 Areas of Specialization
Bowie Specialty
Frisco Specialty
Bonham Specialty
Possum Specialty
Quitman Specialty
Cedar Creek Specialty
Glen Rose Specialty
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Center Controllers

• Each sector has a team of 1 to 3 controllers
  assigned
• safely and efficiently move traffic along their
  planned routes
• merge, setup flights for delivery to next
  facility
• must get/give permission to hand-off/receive
  aircraft
• In quiet periods, contiguous sectors may be
  combined
• Each Area has an Area Supervisor
• In Traffic Management Unit, Traffic Management
  Coordinators make strategic decisions about flows
• eg, based on weather and available runways, set
  TRACON arrival rates (aircraft/hour)
• coordinate flow parameters with adjacent
  facilities

21
ARTCC ATC Positions
RADAR or R Position
Radar Associate or D Position
Assistant or ATA Position
Hand-off/ Tracker Position

• Teamwork
• Flexibility
• Technique

22
Sector Workstation
23
Traffic Management Unit(with CTAS)
24
Display System Replacement (DSR) Console
25
En Route Full Data Block
Aircraft Identification
Vector Line
AAL278 330C 068 500
Mode C Altitude X100
Position Symbol
Ground Speed
Beacon Target
Computer Identification Number
Histories
Leader Line
26
Radar Targets/Symbols
(Radar updates every 10-12 seconds)

• Flat track
• Free track
• Coast track
• Primary target
• Secondary target
• Correlated target
• Non-correlated target

27
Center Radar Display
CO 123 350C B757 310
Slide courtesy of Prof. J. Hansman
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Example Scenario
29
ATM Functional Structure
Slide courtesy of Prof. J. Hansman
30
SF Bay Area - East Flow
Slide courtesy of Prof. J. Hansman
31
SF Bay Area - West Flow
Slide courtesy of Prof. J. Hansman
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Capacity Limit Factors

• Airport Capacity
• Runways
• Gates
• Landside Limits
• Weather
• Airspace Capacity
• Airspace Design
• Controller Workload
• Demand
• Peak Demand
• Hub Spoke Networks
• Environmental Limits
• Noise (relates to Airport)
• Emissions (local, Ozone, NOX, CO2)

Slide courtesy of Prof. J. Hansman
33
Schedule Factors

• Peak Demand/Capacity issue driven by airline Hub
  and Spoke scheduling behavior
• Peak demand often exceeds airport IFR capacity
  (VFR/IFR Limits)
• Depend on bank spreading and lulls to recover
• Hub and Spoke amplifies delay
• Hub and spoke is an efficient network
• Supports weak demand markets
• Schedules driven by competitive/market factors
• Operations respond to marketing
• Trend to more frequent services, smaller aircraft
• Ratchet behavior
• Impact of regional jets
• Ultimately, airlines will schedule rationally
• To delay tolerance of the market (delay
  homeostasis)
• Limited federal or local mechanisms to regulate
  schedule

Slide courtesy of Prof. J. Hansman
34
Flight Plans

• Flight plans
• initially filed by airline
• give intent of aircraft (route, altitude,
  take-off time)
• are amended to reflect controller clearance
  changes
• are printed for each sector 20-30 mins before
  aircraft arrives
• printed strips arranged next to radar display in
  rough eta order
• serve as a physical reminder about aircraft
• controllers write clearances by hand on strips
• strips can be physically handed off along with
  aircraft
• flight plans critical to trajectory prediction by
  automation tools

35
Flight Plan Fields
36
Flight Progress Strips
En Route
Number of times flight plan has been amended
Route of flight
Aircraft Identification
Type Equipment
Beacon code
Estimated Time at fix
Type aircraft
330
DFW.\.TXK LIT J6 HVQ LDN JASEN1 IAD o AAL278
SPL FLT
45
AAL278 1 T/B722/R T468 G500
21 068 09
TXK 1930
6262
19
TCAS Equipped
ZTL
LIT
Filed true airspeed
Sector number
Strip number
Fix posting for Sector 21
Altitude
Coordination Symbol to adjacent ATC facility
Ground speed
Coordination fix time
Previous fix
Remarks section
Computer Identification

• Control Symbology
• Red/Black Strip Marking

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Standard Instrument Departure (SID) (Pilots hard
copy)
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Highways of the Sky (Airways)
Jet Routes FL180
IAD
J14
Victor Routes FL180
GSO
(Direct)
SPA
V124
J14
CHA
MEM
J118
LIT
J118
DFW
J66
J66
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Standard Terminal Arrival Route
Depart HDG 190 Expect RV to Final
AAL278, Reduce speed to TWO ONE ZERO, Contact
Dulles Approach ONE TWO ZERO POINT FOUR
FIVE. AAL278, Reducing and switching, Good
Day.
JASEN
GILBY
R-300
LDN
IAD
AML
R-206
R-259
Requested Route
DOCCS
079
FINKS
HVQ
095
Turbojets expect clearance to Cross at 11,000
at 250kts
DILNN
072
BKW
Turbojets Expect Clearance to Cross at FL240
Jasen One Arrival Charleston Transition
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Flight Plan Routes

• Helpful hints
• DFW.DALL5.TXK..LIT.J131.PXV.J29.JHW.J82.ALB.G
  DM2.BOS
• 4 letters 1 number SID or STAR (TRACON route)
• 3 letters waypoint (also indicates VOR nav aid)
• J number jet route (V number victor/vfr
  route)
• .. separates 2 like elements (ABC..DEF)
• . separates 2 un-like elements (ABC.J52)
• Some variations
• Other waypoint types
• lat/long, x/y, radial/distance
• 47N/121W, 437/248, DFW300040

SJC./.TXO..SJT.CUGAR6.IAH
Will enter ZFW at TXO dont need to see earlier
part of route
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Domain Challenges of ATC Automation

• Control techniques very different for different
  facilities (Center, TRACON, Tower)
• Even among same-type facilities, procedures vary
  widely (Chicago Center vs Ft. Worth Center)
• Airspace description data not always easily
  parsed
• Electronic system outputs do not always reflect
  reality
• Every rule has exceptions
• Difficult/costly to change procedures at the
  moment new tools are introduced (need fallback
  position)
• Lots of politics among FAA, unions, airlines...