Department of Transportation 

Federal Aviation Administration 

Terminal Data Link Services in the 

National Airspace System 

15 January 2008 

Version 1.0 

Office of Primary Responsibility: 

Director – Terminal Operations Safety and Support 
Table of Contents 

Terminal Data Link Services in the NAS ....................................................................................... 1 

General........................................................................................................................................ 1 

Clearance Delivery Services....................................................................................................... 1 

PDC......................................................................................................................................... 1 

DCL (ARInc 623/ED85a)....................................................................................................... 5 

DCL (ATN)............................................................................................................................. 5 

Pushback Clearances................................................................................................................... 5 

Pushback Clearance (ARInc 623/ED85a)............................................................................... 5 

Pushback Clearance (ATN) .................................................................................................... 6 

Taxi Clearances........................................................................................................................... 6 

D-TAXI Service (ARInc 623/ED85a) for Departures............................................................ 6 

D-TAXI Service (ARInc 623/ED85a) for Arrivals ................................................................ 6 

D-TAXI Service (ATN) for Departures.................................................................................. 7 

D-TAXI Service (ATN) for Arrivals...................................................................................... 7 

Terminal Information Services................................................................................................... 8 

D-ATIS (ARInc 620).............................................................................................................. 8 

D-ATIS (ARInc 623).............................................................................................................. 8 

D-ATIS (ATN)........................................................................................................................ 8 

Attachment 1 – Data Link Airports in the NAS ............................................................................. 9 

Attachment 2 – FAA’s PDC Testing Requirements..................................................................... 12 

AOC Testing Required With A DLSP...................................................................................... 12 

Limited “Phase In” Testing....................................................................................................... 13 

Transition Test Phase................................................................................................................ 13 

Attachment 3 – Established Data Link Service Providers for the NAS ....................................... 14 

Aeronautical Radio, Inc (ARInc).............................................................................................. 14 

Honeywell Global Data Center................................................................................................. 14 

satcom direct ............................................................................................................................. 14 

Société Internationale de Télécommunications Aéronautiques (S.I.T.A.) ............................... 15 

Universal Weather & Aviation, Inc. ......................................................................................... 15 

Attachment 4 – Requirements for Airline Participation in the FAA’s PDC Service.................... 16 

Attachment 5 – Requirements for GA Participation in the FAA’s PDC Service ......................... 17 

Attachment 6 – Requirements for Aircraft Participation in the FAA’s DCL (623) Service ........ 18 

Attachment 7 – Requirements for Aircraft Participation in the FAA’s DCL (ATN) Service ...... 19 

Attachment 8 – Requirements for Aircraft Participation in the FAA’s Pushback (623) Service . 20 

Attachment 9 – Requirements for Aircraft Participation in the FAA’s Pushback (ATN) Service21 

Attachment 10 – Requirements for Aircraft Participation in the FAA’s D-TAXI (623) Service. 22 

Attachment 11 – Requirements for Aircraft Participation in the FAA’s D-TAXI (ATN) Service

....................................................................................................................................................... 23 

Attachment 12 – Acronyms.......................................................................................................... 24 

Attachment 13 – References for Additional Information ............................................................. 26 

Attachment 14 – Suggested format for hard copy of PDC messages directed at cockpit crew.... 27 

Attachment 15 – Subscriber List Submissions to the FAA .......................................................... 29 

Subscriber List Format.............................................................................................................. 29 

Details on Call Signs................................................................................................................. 30 

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Resolution of Duplicate Call Signs Amongst Multiple Providers............................................ 30 

Subscriber List Submission Deadlines...................................................................................... 30 

Blocked Call Signs.................................................................................................................... 31 

Attachment 16 – FAA Points of Contact...................................................................................... 32 

FAA Washington Headquarters’ Terminal Data Link Representative:.................................... 32 

FAA Technical Representative ................................................................................................. 32 

Index ............................................................................................................................................. 33 

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Terminal Data Link Services in the NAS 

Terminal Data Link Services in the NAS 

General 

In general, data link services are added to the NAS to reduce frequency congestion, aircrew 

workload, controller workload, enhance safety and reduce confusion. 

In an effort to protect these benefits, the agency has adopted the position that there shall be no 

test call signs assigned or used by the users of data link. If a user needs to test their AOC or data 

link capabilities, it will be done in an offline (outside of the NAS) fashion with an A/G DLSP 

where no interconnection with the NAS is possible. Users found violating this policy will not be 

allowed to participate in NAS data link services. 

Data Link services in the NAS may be delivered in a variety of fashions via various 

communications technologies and equipment. This document is not about the technologies nor 

the communications channels employed. 

This document is not intended to be a standards document or statement regarding standards, but 

rather a simple guide to aid the NAS users and providers of Data Link Services. Data Link 

Services in other countries may bear no resemblance to similarly “named” services in the NAS. 

Refer to information from those countries for specifics about the services offered in/from those 

countries. Data Link Services offered or provided in other countries are not mentioned here. 

This document is not intended to be primer on Data Link Services. 

Clearance Delivery Services 

PDC 

PDC is a subscriber based service that is used at the larger airports in the NAS to provide an 

effective and efficient means of delivering departure clearances before aircraft pushback. Data 

Link technologies are utilized within the NAS to provide a PDC message to a subscriber’s AOC. 

Once the PDC message has been deposited on the subscriber’s AOC, it is then retrieved and 

printed by the subscriber through one of several means: 

1. Internet access 

2. Airline Gate Terminal 

3. Airline Operations Area Terminal 

4. FBO Terminal 

5. Cockpit Avionics via A/G or other Data Link 

It is not necessary for an aircraft to be equipped with Data Link avionics for a flight to participate 

in the PDC service. It is only necessary for the flight crew to be able to obtain a printed copy of 

the PDC message prior to pushback through one of these means. The list above is not all 

inclusive, and as technology is deployed by the users of the NAS for various business reasons, 

other means of delivering the printed PDC message to the flight crew may be employed. The 

basic requirements for the delivery of the message to the air crew are: 

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Terminal Data Link Services in the NAS 

1. The contents of the PDC message are to be relayed to the air crew faithfully and without 

modification, omission or alteration of any sort. 

2. If there is any confusion or uncertainty on the part of the flight crew, they are to not use 

the PDC message, but instead contact CD via voice (telephone or radio) and obtain their 

clearance via manual means. 

3. PDC messages will not be accepted by an AOC unless the operator of the AOC is certain 

that the message can be delivered to the intended flight crew. 

How to Subscribe to PDC: 

Airlines: 

Note: Just because a particular airlines subscribes to one or more data link services at one airport 

in the NAS does not mean it subscribes to those same services at other NAS airports where they 

are offered. There may be equipment, personnel, training or other issues preventing the 

subscription to identical services throughout the NAS. That is why it is up to individual airlines 

to determine where they subscribe to data link services, and which service(s) they choose for 

subscription. 

Each airline that wishes to participate in the FAA’s PDC program shall contact the FAA 

Headquarters’ Terminal Data Link Representative (refer to Attachment 16 – FAA Points of 

Contact) to make their request. The FAA Headquarters’ Representative shall coordinate with all 

the effected parties within the FAA (regions, ATCT’s, and support organizations) to ensure there 

are no issues with fulfilling the request. One of the issues that is examined is how the AOC 

applications communicates with the FAA’s PDC service. The following are the known 

possibilities: 

1. The requesting airline is an existing PDC user elsewhere in the NAS and proposes to use 

their existing AOC capability (no AOC testing required). 

2. The requesting airline is an existing PDC user elsewhere in the NAS and proposed to use 

a different AOC capability (AOC testing required with a A/G DLP followed by limited 

“phase in” testing). 

3. The requesting airline is new to PDC in the NAS and proposes to use an established AOC 

provider (a provider that is already providing AOC services “for hire” to other airlines) 

(limited “phase in” testing is required). 

4. The requesting airline is new to PDC in the NAS and proposes to establish an “in house” 

AOC capability using their internal resources (AOC testing required with a A/G DLP 

followed by limited “phase in” testing). 

5. The requesting airline is new to PDC in the NAS and proposes to establish an “in house” 

AOC capability using commercial software and other internal resources (AOC testing 

required with a A/G DLP followed by limited “phase in” testing). 

For a detailed explanation of the different types of testing listed, refer to Attachment 2 – FAA’s 

PDC Testing Requirements. 

Note: Refer to Attachment 4 – Requirements for Airline Participation in the FAA’s PDC Service

for fleet requirements for PDC service. 

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Terminal Data Link Services in the NAS 

General Aviation 

GA operators wishing to subscribe to the PDC service will need to contact one of the established 

DLSP (refer to for a list of the established DLSPs) companies and make arrangements for the 

service. Refer to Attachment 3 – Established Data Link Service Providers for a list of Data Link 

Service Providers in the United States. GA operators are limited to consideration for a single 

PDC per departure terminal per 24 hour period. This means that if the same call sign was used 

earlier in the day, even if PDC was not offered (revision or other reason for denial), PDC cannot 

be offered on subsequent flights in the same 24 hour period. 

New PDC Airport 

When an airport wishes to add the PDC service, once all of the appropriate hardware, software 

and communications equipment and circuits have been installed, then the site will enter into a 

transition test phase. Refer to Attachment 2 – FAA’s PDC Testing Requirements. 

New DLSP 

When a new provider wishes to offer AOC services, it is necessary for them to test their 

applications with an existing A/G DLP. These entities are required to conduct AOC testing with 

a DLP followed by limited “phase in” testing. Refer to Attachment 2 – FAA’s PDC Testing 

Requirements. These new providers will have to make their own arrangements with an 

established A/G DLP to provide the air/ground portion of the service. 

New A/G DLP. 

New A/G DLP providers shall have to enter into offline testing with the FAA in order to 

establish service. 

Architecture 

Subscriber Lists: 

The current architecture of PDC utilizes subscriber lists. There are two basic lists, the airline list 

and the GA list. These lists are maintained separately. 

Airline Subscriber Lists: 

An airline subscriber list is maintained for each PDC airport. That means that just because an 

airline has subscribed to the PDC service at one airport, does not mean that the same airline has 

subscribed at all PDC airports. The airline list contains the first three letters of the airline’s call 

sign. Any flight ID that matches the first three letters is examined to determine if PDC is 

possible. Once this examination has taken place, this flight ID cannot be re-used by PDC until 

the next 24 hour PDC cycle. 

GA Subscriber List: 

A single GA list is utilized at all commercial PDC airports. It is composed of discrete call signs. 

Call signs do not contain dashes or hyphens or other special characters. Call signs always start 

with at least one letter. Subscriber lists submitted which contain invalid call signs will be 

stripped of the invalid call signs before inclusion into the master list distributed to the sites. 

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Terminal Data Link Services in the NAS 

Note: If an aircraft always flies under a call sign instead of using its registration number 

(N-number for US registered aircraft), then having its registration number listed in the GA 

subscriber list serves no purpose. 

If two different service providers “claim” the same call sign, an arbitrary method is used to break 

the tie. It is in everyone’s best interest for such ties to be the exception and kept to a minimum 

and for DLSPs to coordinate amongst themselves when their customers are changing from one 

DLSP to another DLSP. 

AOC computer Applications Related to PDC: 

The user’s AOC computer (this service may be provided by a third party) is responsible for 

accepting or rejecting each PDC message. When the user’s AOC computer accepts the PDC

message, this represents that the owner of the computer service shall make all reasonable efforts 

to provide the PDC message to it’s intended air crew. When the user’s AOC computer rejects a 

PDC message, it is for one or more of the following reasons: 

1. The Call sign listed in the PDC is not for a flight that is known to this AOC. 

2. Unable to accept a PDC for this call sign. 

3. PDC received is a duplicate of a recently received PDC message. 

4. The time stamp on the PDC message is more than 300 seconds different from the current 

Zulu time at the AOC computer. 

5. The AOC was unable to decode the PDC message. 

Note that the aircraft is not part of the PDC message handshake between the FAA and the AOC. 

Limitations: 

PDC does not support revisions in any form, to the flight plan or the clearance. Any flight 

plan that has been revised for any reason is not eligible for PDC service. The source (AT, 

automation, air crew, airline, etc.) of the revision doesn’t matter, the flight is marked as ineligible 

for the PDC service. 

A given call sign can be considered for PDC once in a 24 hours period for a given airport. 

Even if PDC is not delivered for the first occurrence of the call sign during that period, 

subsequent submissions of the same call sign at the same airport will be denied PDC service. 

If there are routing problems within a flight plan, and the en-route facility “tags” the flight plan 

as “FRC” (full route manual clearance required), the flight is ineligible for PDC service. 

PDC is at the option of the CD controller in the tower. If the controller determines that issuing a 

PDC could introduce confusion, the controller is required to withhold PDC service from the 

flight in question and issue a manual verbal clearance to the air crew. 

PDC messages are sent from the tower to the AOC as soon as is practicable. Flight plans are 

received in the tower twenty five to thirty minutes in advance of the P-Time of the flight plan. 

Air crews seeking to retrieve their PDC message from the AOC cannot obtain the PDC message 

before it has been issued by the tower. 

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Terminal Data Link Services in the NAS 

PDC is not available at all airports in the NAS. Refer to Attachment 1 – Data Link Airports in 

the NAS for a list of commercial airports where the PDC service is currently offered. 

Future Enhancements: 

At some point in the future, as a matter of policy, the PDC Service will be discontinued NAS 

wide. Prior to that time, other departure clearance services will be offered to users so as to not 

lose the benefits of Data Link Services for Clearance Delivery. 

DCL (ARInc 623/ED85a) 

Note: The DCL (623) service is in the study phase and is not available for use in the NAS. 

The DCL service is a “request/reply” service. The air crew in the cockpit submits a data link 

request to the ATSP and requests a departure clearance message. The avionics interacts directly 

with the FAA computer systems in the control tower to make the request. Various handshaking 

messages take place between the avionics and the control tower automation systems. DCL does 

not rely on a subscriber list to know “where” to deliver the message, but a subscriber list of sorts 

is still required so that the controller working at the CD position has a way to “know” which 

flights will call for manual clearances, which flights will call for PDC clearances and which 

flights will utilize DCL to make their request via data link. 

DCL (ATN) 

Note: The DCL (ATN) service is in the study phase and is not available for use in the NAS. 

The DCL service is a “request/reply” service. The air crew in the cockpit submits a data link 

request to the ATSP and requests a departure clearance message. The avionics interacts directly 

with the FAA computer systems in the control tower to make the request. Various handshaking 

messages take place between the avionics and the control tower automation systems. DCL does 

not rely on a subscriber list to know “where” to deliver the message, but a subscriber list of sorts 

is still required so that the controller working at the CD position has a way to “know” which 

flights will call for manual clearances, which flights will call for PDC clearances and which 

flights will utilize DCL to make their request via data link. The service utilizes discrete 

addresses for each airframe so equipped. 

Pushback Clearances 

At those airports where there is a non FAA “ramp tower”, pushback clearances would come from 

the ramp tower and not the FAA. For those airports where the ramp(s) is/are controlled by the 

FAA (GC), the FAA would be the provider of the pushback clearances. 

Pushback Clearance (ARInc 623/ED85a) 

Note: The Pushback Clearance (623) service is in the study phase and is not available for use in 

the NAS. 

The Pushback Clearance (623) service is a “request/reply” service. The air crew in the cockpit 

submits a data link request to the ATSP and requests a departure clearance message. The 

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Terminal Data Link Services in the NAS 

avionics interacts directly with the FAA computer systems in the control tower to make the 

request. Various handshaking messages take place between the avionics and the control tower 

automation systems. Pushback Clearance does not rely on a subscriber list to know “where” to 

deliver the message, but a subscriber list of sorts is still required so that the controller working at 

the GC position has a way to “know” which flights will call for manual clearances, which flights 

will call for Pushback Clearance request via data link. 

Pushback Clearance (ATN) 

Note: The Pushback Clearance (ATN) service is in the study phase and is not available for use 

in the NAS. 

The Pushback Clearance(ATN) service is a “request/reply” service. The air crew in the cockpit 

submits a data link request to the ATSP and requests a departure clearance message. The 

avionics interacts directly with the FAA computer systems in the control tower to make the 

request. Various handshaking messages take place between the avionics and the control tower 

automation systems. Pushback Clearance does not rely on a subscriber list to know “where” to 

deliver the message, but a subscriber list of sorts is still required so that the controller working at 

the GC position has a way to “know” which flights will call for manual clearances, which flights 

will call for Pushback Clearance request via data link. 

Taxi Clearances 

D-TAXI Service (ARInc 623/ED85a) for Departures 

Note: The D-TAXI (623) service is in the study phase and is not available for use in the NAS. 

In order for D-TAXI service to be available for a departure, it is necessary for the automation 

system on the ground to know a few pieces of information before the controller can assign a 

departure taxi route: 

1. Where (as in which gate or stand) is the aircraft located on the airport surface? 

2. Which specific runway will the aircraft use for take off? 

3. What kind (make and model) of aircraft is making the request? 

The “where” and the “which” are somewhat obvious because you have to know where someone 

is currently located and where they want to go to be able to tell them how to get there. The 

“what kind” comes into play where there are clearance issues (wing span) as well as pavement 

loading issues (overall gross weight as well as weight per truck). All of these pieces of 

information are used to determine the best route(s) that can be selected by the controller. 

D-TAXI Service (ARInc 623/ED85a) for Arrivals 

In order for D-TAXI (623) service to be available for an arrival, it is necessary for the 

automation system on the ground to know a few pieces of information before the controller can 

assign an arrival taxi route: 

1. Which specific runway will the aircraft use for landing, as well as which taxiway turnoff 

will be used after landing? 

15 January 2008 Page 6 Version 1.0 
Terminal Data Link Services in the NAS 

2. Where (as in which gate or stand) is the aircraft going to park on the airport surface? 

3. What kind (make and model) of aircraft is making the request? 

The “which” and the “where” are somewhat obvious because you have to know where someone 

is going to be located and where they want to go to be able to tell them how to get there. The 

“what kind” comes into play where there are clearance issues (wing span) as well as pavement 

loading issues (overall gross weight as well as weight per truck). All of these pieces of 

information are used to determine the best route(s) that can be selected by the controller. 

D-TAXI Service (ATN) for Departures 

Note: The D-TAXI (ATN) service is in the study phase and is not available for use in the United 

States. 

In order for D-TAXI service to be available for a departure, it is necessary for the automation 

system on the ground to know a few pieces of information before the controller can assign a 

departure taxi route: 

1. Where (as in which gate or stand) is the aircraft located on the airport surface? 

2. Which specific runway will the aircraft use for take off? 

3. What kind (make and model) of aircraft is making the request? 

The “where” and the “which” are somewhat obvious because you have to know where someone 

is currently located and where they want to go to be able to tell them how to get there. The 

“what kind” comes into play where there are clearance issues (wing span) as well as pavement 

loading issues (overall gross weight as well as weight per truck). All of these pieces of 

information are used to determine the best route(s) that can be selected by the controller. 

D-TAXI Service (ATN) for Arrivals 

In order for D-TAXI (ATN) service to be available for an arrival, it is necessary for the 

automation system on the ground to know a few pieces of information before the controller can 

assign an arrival taxi route: 

1. Which specific runway will the aircraft use for landing, as well as which taxiway turnoff 

will be used after landing? 

2. Where (as in which gate or stand) is the aircraft going to park on the airport surface? 

3. What kind (make and model) of aircraft is making the request? 

The “which” and the “where” are somewhat obvious because you have to know where someone 

is going to be located and where they want to go to be able to tell them how to get there. The 

“what kind” comes into play where there are clearance issues (wing span) as well as pavement 

loading issues (overall gross weight as well as weight per truck). All of these pieces of 

information are used to determine the best route(s) that can be selected by the controller. 

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15 January 2008 Page 8 Version 1.0 

Terminal Information Services 

D-ATIS (ARInc 620) 

Currently, in the United States, D-ATIS is an ARInc 620 “free text” message. These messages 

are currently warehoused within the ARInc network. At some point in the future, these messages 

will be warehoused within the confines of the FAA network(s). 

D-ATIS (ARInc 623) 

Note: The D-ATIS (623) service is in the study phase and is not available for use in the NAS. 

D-ATIS (ATN) 

Note: The D-ATIS (ATN) service is in the study phase and is not available for use in the NAS. 
Terminal Data Link Services in the NAS 

Attachment 1 – Data Link Airports in the NAS 

Site ID State Data Link Services Available Commercial Airport Co

ANC Alaska PDC, D-ATIS(Arrival and Departure) Anchorage International Airport PHX Arizona PDC, D-ATIS(Arrival and Departure) Phoenix-Sky Harbor InternationaLIT Arkansas PDC, D-ATIS(Combined) Little Rock Adams Field Airport BUR California PDC, D-ATIS(Combined) Burbank/Glendale/Pasadena AirpLAX California PDC, D-ATIS(Arrival and Departure) Los Angeles International Airport OAK California PDC, D-ATIS(Arrival and Departure) Oakland International Airport ONT California PDC, D-ATIS(Arrival and Departure) Ontario International Airport SAN California PDC, D-ATIS(Arrival and Departure) San Diego (Lindbergh) InternatioSFO California PDC, D-ATIS(Arrival and Departure) San Francisco International AirpoSJC California PDC, D-ATIS(Combined) San Jose Municipal Airport SMF California PDC, D-ATIS(Arrival and Departure) Sacramento International Airport SNA California PDC, D-ATIS(Arrival and Departure) John Wayne (Orange County) AiDEN Colorado PDC, D-ATIS(Arrival and Departure) Denver International Airport BDL Connecticut PDC, D-ATIS(Arrival and Departure) Bradley International Airport DCA District of Columbia PDC, D-ATIS(Arrival and Departure) Washington Reagan National AirFLL Florida PDC, D-ATIS(Arrival and Departure) Fort Lauderdale-Hollywood InternJAX Florida PDC, D-ATIS(Arrival and Departure) Jacksonville International Airport MCO Florida PDC, D-ATIS(Arrival and Departure) Orlando International Airport MIA Florida PDC, D-ATIS(Arrival and Departure) Miami International Airport PBI Florida PDC, D-ATIS(Arrival and Departure) Palm Beach International Airport TPA Florida PDC, D-ATIS(Arrival and Departure) Tampa International Airport ATL Georgia PDC, D-ATIS(Arrival and Departure) Atlanta International Airport HNL Hawaii PDC, D-ATIS(Arrival and Departure) Honolulu International BOI Idaho PDC, D-ATIS(Arrival and Departure) Boise Air Terminal 15 January 2008 Page 9 Version 1.0 
Terminal Data Link Services in the NAS 

Site ID State Data Link Services Available Commercial Airport Co

MDW Illinois PDC, D-ATIS(Arrival and Departure) Chicago-Midway Airport ORD Illinois PDC, D-ATIS(Arrival and Departure) Chicago-O'Hare International AirpIND Indiana PDC, D-ATIS(Arrival and Departure) Indianapolis Airport CVG Kentucky PDC, D-ATIS(Arrival and Departure) Cincinnati/Northern Kentucky InteSDF Kentucky PDC, D-ATIS(Arrival and Departure) Sandiford (Louisville) Field MSY Louisiana PDC, D-ATIS(Arrival and Departure) New Orleans International AirporBWI Maryland PDC, D-ATIS(Arrival and Departure) Baltimore-Washington InternationBOS Massachusetts PDC, D-ATIS(Arrival and Departure) Boston Logan International AirpoDTW Michigan PDC, D-ATIS(Arrival and Departure) Detroit Metro (Wayne County) AiMSP Minnesota PDC, D-ATIS(Arrival and Departure) Minneapolis-St Paul International MCI Missouri PDC, D-ATIS(Arrival and Departure) Kansas City International Airport STL Missouri PDC, D-ATIS(Arrival and Departure) Saint Louis Lambert InternationaOMA Nebraska PDC, D-ATIS(Arrival and Departure) Eppley (Omaha) Airfield LAS Nevada PDC, D-ATIS(Arrival and Departure) McCarran (Las Vegas) InternatioRNO Nevada PDC, D-ATIS(Arrival and Departure) Reno-Tahoe International Airport EWR New Jersey PDC, D-ATIS(Arrival and Departure) Newark Liberty International AirpTEB New Jersey PDC, D-ATIS(Arrival and Departure) Teterboro Airport ABQ New Mexico PDC, D-ATIS(Arrival and Departure) Albuquerque International Airport ALB New York PDC, D-ATIS(Arrival and Departure) Albany International Airport BUF New York PDC, D-ATIS(Arrival and Departure) Buffalo International Airport HPN New York PDC, D-ATIS(Arrival and Departure) Westchester County (White PlainJFK New York PDC, D-ATIS(Arrival and Departure) New York JFK International AirpoLGA New York PDC, D-ATIS(Arrival and Departure) New York La Guardia Airport CLT North Carolina PDC, D-ATIS(Arrival and Departure) Charlotte-Douglas International AGSO North Carolina PDC, D-ATIS(Arrival and Departure) Piedmont Triad (Greensboro) InteRDU North Carolina PDC, D-ATIS(Arrival and Departure) Raleigh-Durham Airport CLE Ohio PDC, D-ATIS(Arrival and Departure) Cleveland-Hopkins International A15 January 2008 Page 10 Version 1.0 
Terminal Data Link Services in the NAS 

15 January 2008 Page 11 Version 1.0 

Site ID State Data Link Services Available Commercial Airport Co

CMH Ohio PDC, D-ATIS(Arrival and Departure) Port Columbus International AirpoOKC Oklahoma PDC, D-ATIS(Combined) Will Rogers World Airport TUL Oklahoma PDC, D-ATIS(Arrival and Departure) Tulsa International Airport PDX Oregon PDC, D-ATIS(Arrival and Departure) Portland International Airport PHL Pennsylvania PDC, D-ATIS(Arrival and Departure) Philadelphia International Airport PIT Pennsylvania PDC, D-ATIS(Arrival and Departure) Pittsburgh International Airport SJU Puerto Rico PDC, D-ATIS(Arrival and Departure) San Juan Luis Munoz Marin InterPVD Rhode Island PDC, D-ATIS(Arrival and Departure) Theodore Francis Green (ProvideBNA Tennessee PDC, D-ATIS(Arrival and Departure) Nashville International Airport MEM Tennessee PDC, D-ATIS(Arrival and Departure) Memphis International Airport AUS Texas PDC, D-ATIS(Arrival and Departure) Austin Bergstrom International AiDAL Texas PDC, D-ATIS(Arrival and Departure) Dallas Love Field DFW Texas PDC, D-ATIS(Arrival and Departure) Dallas Fort Worth International AELP Texas PDC, D-ATIS(Arrival and Departure) El Paso International Airport HOU Texas PDC, D-ATIS(Arrival and Departure) William P Hobby (Houston) AirpoIAH Texas PDC, D-ATIS(Arrival and Departure) George Bush Intercontinental/HoSAT Texas PDC, D-ATIS(Arrival and Departure) San Antonio International Airport SLC Utah PDC, D-ATIS(Arrival and Departure) Salt Lake City International AirpoIAD Virginia PDC, D-ATIS(Arrival and Departure) Washington Dulles International ASEA Washington PDC, D-ATIS(Arrival and Departure) Sea-Tac International Airport MKE Wisconsin PDC, D-ATIS(Arrival and Departure) General Mitchell (Milwaukee) Inte
Terminal Data Link Services in the NAS 

Attachment 2 – FAA’s PDC Testing Requirements 

There are various levels of testing that are required to ensure compatibility between the FAA 

PDC service and a user’s AOC application. Depending on certain factors, a user may be 

required to accomplish in depth testing with their A/G DLP in advance of the FAA configuring 

the user in the PDC application. These same factors may only require a limited “phase in” 

testing. There are even situations where no testing is required. 

AOC Testing Required With A DLSP 

This type of testing is accomplished to ensure that the AOC PDC Message handling software 

handles the following: 

1. Ability to positively reply to those PDC messages where the intended recipient flight 

crew is known to the AOC application to be capable of utilizing the PDC Information. 

2. Ability to negatively reply to those PDC messages where: 

a. The intended recipient is not known to the AOC application. 

b. Flight ID received from the FAA is not known to the AOC application. 

c. Route information received from the FAA is incomplete or unrecognizable as a 

flight known to the AOC. 

d. Departure point listed in the PDC message is incorrect for the flight ID in the 

PDC message. 

e. The PDC timestamp is more than 300 seconds different than the time received in 

the AOC computer application. 

f. The PDC message received is garbled or unintelligible. 

g. Unable to accept a PDC for this call sign. 

h. PDC received is a duplicate of a recently received PDC message. 

i. The AOC was unable to decode enough of the PDC message to determine it is 

valid for their purposes. 

3. Ability to provide the aircraft registration number. The AOC software shall include the 

aircraft registration number in the appropriate field as part of a positive 

acknowledgement. For data link equipped aircraft utilizing the 623 protocol, the 

registration number is generally the data link “address” of the aircraft. Providing this 

information enables the FAA to send unsolicited information to the air crew in the future. 

4. Ability to provide an accurate gate/stand identifier in the positive acknowledgement. The 

gate/stand must be one shown or listed on the airport diagram for the departure airport of 

the flight. Having this information will help the FAA in the future by allowing the FAA 

to pre-plan the taxi route(s). Note that the character “G” by itself does not satisfy this 

requirement. Those flights that do not provide accurate or recognized gate/stand 

identifiers may not be allowed to participate in data link services requiring accurate 

gate/stand information. 

5. PDC messages from the FAA shall always be responded to with either a positive 

acknowledgement (AOC accepts and promises to ensure delivery of PDC to appropriate 

air crew), or a negative acknowledgement (AOC is unable to accept and/or unable to 

promise delivery of PDC to appropriate air crew). 

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The engineering staff of the A/G DLP that conducted the AOC testing will furnish the FAA with 

an end of test report which details the results of the DLSP testing. At a minimum, the areas 

listed above will be addressed and the results provided. The FAA will evaluate the report and 

make a determination as to whether additional testing or clarification is required, or if the request 

for the user can begin to move forward. 

Limited “Phase In” Testing 

This type of testing is used to validate configuration changes to ensure that the AOC provider 

and the FAA have compatible operations. This type of testing entails the FAA configuring a 

limited set of call signs (discrete call signs, 10 or less) to ensure that all of the network routing 

and adaptations are compatible. With less than 10 call signs in play, it allows for problems to 

occur that are not operationally significant in nature to the airline or the FAA. If no problems 

occur, then at the end of 30 days, the 10 discrete call sign limit is removed, and all flights for a 

given airline are allowed to participate in the PDC service at that location. 

Transition Test Phase 

This is used when a new PDC site is preparing to enter into full operational capability. For a 

minimum of 30 days, the site where the new PDC service is located will use PDC with a “guinea 

pig” user. The service will be limited to this one user. Criteria for the selection of the user: 

1. Less than 20 flights per day from the facility. 

2. User’s fleet is 100% capable of using PDC from the airport under test. 

3. User is an established user of PDC elsewhere in the NAS. 

Once the new terminal site is capable of sending PDC’s and receiving the reply messages error 

free (no timeouts or other communications errors) for 30 days, then the site can enter operational 

service and allow other established users of PDC to begin requesting and utilizing the PDC 

service. For those sites with no scheduled airline service, 20 discrete, established (as in the users 

of the call signs are already experienced PDC users elsewhere in the NAS) call signs shall be 

utilized. 

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Attachment 3 – Established Data Link Service Providers for 

the NAS 

The following is a list of companies that offer data link services to the aviation industry in the 

United States. The listed companies have accomplished testing and established themselves as 

capable of being able to provide data link and AOC services in the United States. Their 

inclusion in this list does not constitute an endorsement of any of these companies by the FAA or 

the United States Government1

: 

Aeronautical Radio, Inc (ARInc) 

2551 Riva Road 

Annapolis, Maryland 21401-7435 

Telephone Number: (410) 266-4000 

Web: http://www.arinc.com

email: none listed 

PDC Notes: AOC Service Provider, A/G Data-Link Provider 

Honeywell Global Data Center 

15001 NE 36th Street 

Redmond, Washington 98052 

Telephone: (425) 885-8100 

Web: http://www.mygdc.com

Email: gfo@mygdc.com

PDC Notes: AOC Service Provider 

satcom direct 

1901 Hwy A1A 

Satellite Beach, Florida 32937 

Telephone: (321) 777-3000 

Web: http://www.satcomdirect.com

Email: support@satcomdirect.com

PDC Notes: AOC Service Provider, Satellite (Air/Ground data link via satellite only) Data Link 

Provider 

 

1

 This list will be updated from time to time as resources permit and posted to the FAA’s web site at 

http://www.faa.gov

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Société Internationale de Télécommunications Aéronautiques 

(S.I.T.A.) 

North America 

3100 Cumberland Boulevard 

Atlanta, Georgia 30339 

(780) 850-4500 

Web: http://www.sita.aero

e-mail: info.northamerica@sita.aero

PDC Notes: A/G Data-Link Provider 

Universal Weather & Aviation, Inc. 

8787 Tallyho Street 

Houston, Texas 77061-3429 

Telephone: (713) 944-1622 ext. 3300 

Web: http://www.univ-wea.com

e-mail: sales@universalweather.com

PDC Notes: AOC Service Provider 

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Attachment 4 – Requirements for Airline Participation in the 

FAA’s PDC Service 

For an airline to participate in the PDC service at a departure terminal facility, some 

requirements have to be met: 

1. 100% of the airline’s flights originating from the terminal facility in question have to be 

capable of obtaining the PDC message through some means from their AOC prior to 

pushback. 

2. The airline’s aircrews have to be able to utilize the PDC message from the terminal 

facility. 

3. Airlines AOC’s that reject 15% or more of the PDC messages offered at a given site may 

be dropped from the PDC service at that site. 

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Attachment 5 – Requirements for GA Participation in the 

FAA’s PDC Service 

For a GA operator to participate in the PDC service at a departure terminal facility, some 

requirements have to be met: 

1. Subscribe to the PDC service through a DLSP. 

2. The aircrews have to be able to utilize the PDC message from the terminal facility. 

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Attachment 6 – Requirements for Aircraft Participation in the 

FAA’s DCL (623) Service 

For an aircraft to participate in the DCL(623) service at a departure terminal facility, some 

requirements have to be met: 

1. The aircraft has to be equipped with avionics that are capable of utilizing the 623 

protocol for DCL (version 2 of DCL preferred). 

2. The airline’s aircrews have to be able to utilize the DCL message from the terminal 

facility. 

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Attachment 7 – Requirements for Aircraft Participation in the 

FAA’s DCL (ATN) Service 

For an aircraft to participate in the DCL(ATN) service at a departure terminal facility, some 

requirements have to be met: 

1. The aircraft has to be equipped with avionics that are capable of utilizing the ATN 

protocol for DCL. 

2. The airline’s aircrews have to be able to utilize the DCL message from the terminal 

facility. 

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Attachment 8 – Requirements for Aircraft Participation in the 

FAA’s Pushback (623) Service 

For an aircraft to participate in the Pushback Clearance(623) service at a departure terminal 

facility, some requirements have to be met: 

1. The aircraft has to be equipped with avionics that are capable of utilizing the 623 

protocol for Pushback Clearance. 

2. The airline’s aircrews have to be able to utilize the Pushback Clearance message from the 

terminal facility. 

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Attachment 9 – Requirements for Aircraft Participation in the 

FAA’s Pushback (ATN) Service 

For an aircraft to participate in the Pushback Clearance(ATN) service at a departure terminal 

facility, some requirements have to be met: 

1. The aircraft has to be equipped with avionics that are capable of utilizing the ATN 

protocol for Pushback Clearance. 

2. The airline’s aircrews have to be able to utilize the Pushback Clearance message from the 

terminal facility. 

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Attachment 10 – Requirements for Aircraft Participation in the 

FAA’s D-TAXI (623) Service 

For an aircraft to participate in the D-TAXI(623) service at a departure terminal facility, some 

requirements have to be met: 

1. The aircraft has to be equipped with avionics that are capable of utilizing the 623 

protocol for D-TAXI Service. 

2. The airline’s aircrews have to be able to utilize the D-TAXI message from the terminal 

facility. 

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Attachment 11 – Requirements for Aircraft Participation in the 

FAA’s D-TAXI (ATN) Service 

For an aircraft to participate in the D-TAXI(623) service at a departure terminal facility, some 

requirements have to be met: 

1. The aircraft has to be equipped with avionics that are capable of utilizing the ATN 

protocol for D-TAXI Service. 

2. The airline’s aircrews have to be able to utilize the D-TAXI message from the terminal 

facility. 

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Attachment 12 – Acronyms 

A/G Air Ground 

AOC Airline Operations Computer 

ARInc 620 ARInc Standard #620 

ARInc 623 ARInc Standard #623 (supplanted by ED85a) 

AT Air Traffic 

ATC Air Traffic Control 

ATCT Air Traffic Control Tower 

ATIS Automatic Terminal Information Service 

ATN Aeronautical Telecommunications Network 

CD Clearance Delivery 

CONUS Continental United States 

D-ATIS Digital ATIS 

DCL Departure Clearance Request 

DLP Data Link Provider 

DLSP Data Link Service Provider 

DOT Department of Transportation 

ED85a EUROCAE Standard 85, modification “a” 

EDCT “Edict” (Estimated Departure Clearance Time) Time 

FAA Federal Aviation Administration 

GA General Aviation 

GC Ground Control (FAA) 

NAS National Airspace System 

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OCONUS Outside CONUS 

P-Time Proposed Time 

PDC Pre-Departure Clearance 

TDLS Tower Data Link Services 

UTC Coordinated Universal Time 

Zulu Z-Time, slang for Coordinated Universal Time 

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Attachment 13 – References for Additional Information 

The following documents should be referred to regarding the various data link services offered 

by the agency: 

FAA Order 7032.11 – Air Traffic Operational Requirements for the Pre-Departure Clearance 

System (PDC) 

FAA Order 7032.12 – Air Traffic Operational Requirements for Tower Automation Systems 

FAA Order 7110.113C – Procedures for Issuing Automated Clearances 

ARInc Document 12889 Rev H PreDeparture Clearance Application Segment Specification 

dated September 29, 1999 – Copyrighted © 1999 by Aeronautical Radio Incorporated – 

Available from ARInc only 

FAA Document – PreDeparture Clearance Application Segment Specification dated June 2, 2000 

As other data link services within the NAS move closer to being available, additional entries will 

appear in this attachment. 

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Attachment 14 – Suggested format for hard copy of PDC 

messages directed at cockpit crew 

In order to minimize confusion, the following format is suggested for use by cockpit crews. 

First, some terminology: 

Computer ID: CCC (where CCC is the FAA computer ID assigned to this flight 

Flight ID: FFFFFFF (flight ID/Call sign of the flight) 

Beacon Code: BBBB (4 digit beacon or “squawk” code assigned to this flight) 

Departure Point: DDDD (3/4 character departure point ID) 

Equipment Type: 

H/GGGG/N (Number of Aircraft and or Heavy Indicator/Aircraft Type/Aircraft Equipment) 

Requested Altitude: AAA (Flight Level – altitude in hundreds of feet) 

Estimated Departure Clearance Time (EDCT): EEEE (when no EDCT time is provided, the word 

“None” may be substituted. 

Proposed Time (P-Time): PPPPP 

Departure Frequency Information: IIII (one line of text with departure frequency information) 

Altitude restriction data field: JJJ (one line of text with altitude restriction information) 

Standard Instrument Departure(SID) data field: SSS (one line of text with SID information) 

Route of flight: RRR (list of way points/identifiers for the route of flight – up to 3 lines of way 

points/identifiers, separated by spaces) 

Free Text Line 1: TTT (one line of text with free text information) 

Free Text Line 2: UUU (one line of text with free text information) 

Free Text Line 3: VVV (one line of text with free text information) 

The above items are provided in the PDC message sent from the FAA tower to the AOC 

computers. It is suggested that it be provided to the cockpit crews in the following format. The 

items in bold text are fixed and do not vary. The items in italic text represent the information 

received from the FAA tower. It is not appropriate to insert/delete/interpret this information. 

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Sample PDC hardcopy message: 

Pre-Departure Clearance Start 

Call sign: FFFFFFF Beacon Code: BBBB

Flight Level: AAA Computer ID: CCC

Proposed Time: PPPPP EDCT Time: EEEE

Departing From: DDDD

Equipment: H/GGGG/N

Approved Route: 

RRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRR 

RRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRR 

RRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRR 

Departure Frequency Information: 

IIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIII 

Altitude Restrictions: 

JJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJ 

SID Information: 

SSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSS 

Additional Information: 

TTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTT 

UUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUU 

VVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVV 

Pre-Departure Clearance End 

Notes: 

1. Phrases such as “Cleared as filed” or “revisions” should never be used by the AOC in 

presenting the PDC message to the cockpit crew. 

2. It is not necessary to present the Strip Request Originator field to the cockpit crew. 

3. It is not necessary to provide the revision number field since flights carrying a 

revision number are never eligible for PDC messages or PDC services. 

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Attachment 15 – Subscriber List Submissions to the FAA 

Data Link Service Providers notify the FAA of the subscribers of data link services via 

scheduled updates. Qualified Data Link Service Providers provide their subscriber customer 

information in the following format to the FAA. 

Subscriber List Format 

• Valid FAA Call sign 

• The ASCII Colon (:) character 

• The Provider ID (assigned by the FAA) 

• The ASCII Colon (:) character 

• The 7 letter destination address for PDC (AOC Address) 

• The ASCII Colon (:) character 

• The possible data link ATSP services contracted for this call sign, separated by ASCII 

comma (,) characters (the services can appear in any order). 

o PDC (Pre-Departure Clearance - this is the only supported service at this time) 

o D23 (623 Departure Clearance – not supported at this time) 

o T23 (623 Taxi Clearance – not support at this time) 

o DTN (ATN Departure Clearance – not supported at this time) 

o TTN (ATN Taxi Clearance – not supported at this time) 

o P23 (623 Pushback Clearance – not supported at this time) 

o PTN (ATN Pushback Clearance – not supported at this time) 

• The ASCII Colon (:) character 

• The 7 letter destination address for carbon copies of 623/ATN Departure Clearances. 

This is usually an AOC address. 

• The ASCII Colon (:) character 

• Special use Code. Unless directed otherwise by the FAA, this code is the ASCII 

character upper case C. 

• The ASCII Colon (:) character 

• The Zulu date the subscription starts for this customer 

o YYYY ASCII character 4 digit year 

o MM ASCII character 2 digit (zero fill) month 

o DD ASCII character 2 digit (zero fill) day 

• The ASCII Colon (:) character 

• The Zulu time the subscription starts for this customer 

o HH ASCII character 2 digit (zero fill) hour (24 hour format) 

o MM ASCII character 2 digit (zero fill) minutes 

• The ASCII Colon (:) character 

• The Zulu date the subscription ends for this customer 

o YYYY ASCII character 4 digit year 

o MM ASCII character 2 digit (zero fill) month 

o DD ASCII character 2 digit (zero fill) day 

• The ASCII Colon (:) character 

• The Zulu time the subscription ends for this customer 

o HH ASCII character 2 digit (zero fill) hour (24 hour format) 

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o MM ASCII character 2 digit (zero fill) minutes 

• The ASCII Colon (:) character 

• Optional 30 character comment field (ASCII Text only, no colons) 

• The ASCII carriage return character 

• The ASCII line feed character 

Details on Call Signs 

Tail numbers (as well as call signs) contain only letters and numbers. No dashes/hyphens (call 

signs with dashes/hyphens/illegal characters are completely discarded). 

The rules for airline call signs: The first three letters are the ICAO identifier, followed by a 

flight number, no spaces, no leading zeroes in the flight number. The use of airline call signs in 

the GA file is discouraged, and new ones will be admitted on a case by case basis. Call signs for 

airline fleets do not belong in the GA file. 

If you have an air carrier that utilizes call signs (charter operator for example), if the entire fleet 

of the operator that will be using PDC is a single provider (DLSP) customer, then their calls 

signs do NOT go in the GA file, but instead, that coordination will take place like that of an 

airline. Don't put 100 different call signs in the file for the same outfit, if they use PDC for all of 

their airframes. Instead, get with Gary Norek and coordinate it as a new airline customer. 

If you have a customer that always uses a call sign, and never uses their tail number for filing 

flight plans, then don't put the tail number in the file. Data Link services are targeted to the call 

sign of the flight plan. The only time data link services are target at the tail number is when the 

tail number is used as the call sign on the flight plan. 

Resolution of Duplicate Call Signs Amongst Multiple Providers 

PDC does not support multiple providers for a single call sign. 

How will aircraft registration number duplications between the various data link providers be 

coordinated and resolved prior to use of the subscriber lists? 

1.) The provider that shows the earliest contract date/time gets the subscription. 

2.) In the event of a duplicate contract start date/time, the FAA will use a random 

method for “choosing” which provider will receive the traffic for this 

customer for this update period. 

Subscriber List Submission Deadlines 

Submit the information NLT than COB (17:00 Central time) on the 13th of the month. In 

addition, we need your information 2 days before the beginning of the next month, NLT than 

COB (17:00 Central time). (Example, for a month with 28 days, we need it by COB on the 27th 

for the following month) 

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Blocked Call Signs 

Blocked call signs will be removed from the submitted lists and blocked from participation. For 

those call signs that have proven to be problematic to the safe operation of the NAS, the FAA 

reserves the right to block those call signs from participation in Data Link Services.

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Attachment 16 – FAA Points of Contact 

FAA Washington Headquarters’ Terminal Data Link Representative: 

Federal Aviation Administration 

Mr. Gary A Norek 

600 Independence Avenue SW 

Washington, DC 20591 

Telephone: (202) 385-8510 

e-mail: gary.a.norek@faa.gov

FAA Technical Representative 

Federal Aviation Administration 

Mr. Russell Davis 

6500 South MacArthur Boulevard 

Building 189 

Oklahoma City, Oklahoma 73169 

Telephone: (405) 954-9716 

e-mail: russell.davis@faa.gov

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Index 

Air Ground................................................................................................ 1, 2, 3, 12, 13, 14, 15, 24 

AOC .............................................................................. 1, 2, 3, 4, 12, 13, 14, 15, 16, 24, 27, 28, 29

ARInc 620................................................................................................................................. 8, 24 

ARInc 623..................................................................................... 5, 6, 8, 12, 18, 20, 22, 23, 24, 29 

AT ............................................................................................................................................. 4, 24 

ATC............................................................................................................................................... 24 

ATCT ........................................................................................................................................ 2, 24 

ATIS.......................................................................................................................... 8, 9, 10, 11, 24 

ATN ...................................................................................................... 5, 6, 7, 8, 19, 21, 23, 24, 29 

CD..................................................................................................................................... 2, 4, 5, 24 

CONUS................................................................................................................................... 24, 25 

D-ATIS ..................................................................................................................... 8, 9, 10, 11, 24 

DCL......................................................................................................................... 5, 18, 19, 24, 29 

DLP........................................................................................................................... 2, 3, 12, 13, 24 

DLSP..................................................................................................... 1, 2, 3, 4, 12, 13, 17, 24, 30 

DOT .............................................................................................................................................. 24 

D-TAXI........................................................................................................................... 6, 7, 22, 23 

ED85a ................................................................................................................................... 5, 6, 24 

EDCT ................................................................................................................................ 24, 27, 28 

FAA............................................................................................................. 2, 4, 5, 6, 12, 13, 14, 24 

GA............................................................................................................................. 3, 4, 17, 24, 30 

GC......................................................................................................................................... 5, 6, 24 

NAS..................................................................................................... 1, 2, 5, 6, 8, 9, 13, 14, 24, 26 

OCONUS ...................................................................................................................................... 25 

PDC......................................... 1, 2, 3, 4, 5, 9, 10, 11, 12, 13, 14, 15, 16, 17, 25, 26, 27, 28, 29, 30 

P-Time................................................................................................................................. 4, 25, 27 

TDLS............................................................................................................................................. 25 

UTC............................................................................................................................................... 25 

Zulu..................................................................................................................................... 4, 25, 29 

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