the global link - rockwell collins - building trust every day global link may 2011 | #42 ... is...

The Global Link May 2011 | #42

Chairman’s Perspective:

Always Moving Forward

1. Spotlight on David Zeigler

2. Reintroducing AeroConnxTM

eEnabled Aircraft Solutions

and ARINC GateFusionSM

4. ARINC OpCenterSM FANS

Management

5. ARINC in Asia: Enhancing

Flight Safety in Asia

7. ARINC in Europe, the Middle

East, and Africa: Link2000+

In Full Swing

8. GLOBALinkSM/HFDL: Solar Cycle

23/24: A Tale of Two Suns

9. GLOBALink/Satellite: Ancillary

Terrestrial Component (ATC)

Concerns Increase

10. GLOBALink/Iridium: FANS Over

Iridium (FOI) and Iridium NEXT

11. GLOBALink Radio Installation &

Maintenance: Narrowbanding

12. Technotalk: VDL Mode 2:

Expanding the Capacity to

Meet the Demands of the

Future…

15. VHF: A Project Engineer’s

Perspective

2551 Riva Road, Annapolis, MD 21401 USA | +1 800.633.6882 | arinc.com

A Newsletter for the Aviation Industry

The Global Link

May 2011 | #42 The Global Link

Chairman’s Perspective

Always Moving Forward

From our beginning in 1929, ARINC’s unique knowledge of the aviation industry’s needs

has given us the distinct perspective and advantage to understand how they will evolve over

time. It’s what led to the air/ground VHF data link revolution more than thirty years ago. It’s

why we were able to build ACARS® into the industry standard. It’s why in the 1990’s ARINC

anticipated the coming need for greater bandwidth in the VHF spectrum and introduced VHF

Digital Link Mode 2 (VDL Mode 2). It’s also why right now GLOBALinkSM is still growing and

building our data link infrastructure, enhancing services as customers’ needs change, adding

capabilities so our customers thrive, investing in the technology’s future so our customers

can be assured their investment remains sound. GLOBALink is always moving forward.

Air Traffic Services, electronic flight charts and engine health monitoring programs are just

some of the advanced implementations geared towards safer, more efficient operations.

These critical applications are possible because of VDL Mode 2’s bit-oriented architecture

that delivers 10 times the message capacity of the original analog ACARS system. Today,

VDL Mode 2 is the new data link standard in the aviation industry.

VDL Mode 2 supports the busiest airspaces in 19 countries, carrying millions of messages

per month to more than 25% of the world’s commercial aircraft. In fact, every year VDL

Mode 2 usage and aircraft equipage grows. In the United States alone, ARINC is operating

over 300 VDL Mode 2 ground stations, and adding more each year to stay ahead of our

customers’ needs. For us, NextGen is already here and VDLM2 is ready to provide value to

aircraft operators. ARINC’s VDL Mode 2 network is built to enable the FAA’s next generation

of air traffic control technology today, including revised clearances at the 65 FAA Tower Data

Link Services (TDLSSM) airports.

Every day GLOBALink is engineering and securing VDL Mode 2’s future. In fact, ARINC is

working with avionics and airframe manufacturers on ways to exponentially increase its value

and versatility in the market place. The greater the capacity and usage of data link, the less

reliance the industry will have on voice communications. The easier ARINC and VDL Mode 2

can help make using data link communications, the more errors from misunderstood voice

contacts will be reduced. All of this leads to more timely and concise clearances, more

orderly flow and fewer deviations during peak traffic hours. And, ultimately this equates to

safer, more efficient and more cost-effective operations. We know that’s not only how you

retain customers; it’s how you build the trust and confidence of new ones.

Always Moving Forward—That’s how GLOBALink perpetuates the thrust of an industry

evolving and adapting every day.

John Belcher Chairman and Chief Executive Officer, ARINC

May 2011 | #42The Global Link

1

Spotlight on David Zeigler

A recent addition to ARINC, David Zeigler has brought his experience working for an original

equipment manufacturer to his new position, developing ARINC’s relationships with aircraft

and avionics OEMs.

As Business Development Director in the Commercial Aviation Solutions group, he asks

the questions that further those relationships: where are we today, what developments

could ARINC support moving forward, what are the OEMs’ plans moving toward NexGen

or DataCom?

In addition, he has been working with several of the OEMs to establish an ATN Test Cloud

for the development and interoperability testing of Link2000+ avionics.

Coming from an OEM, he always admired and enjoyed working with the team at ARINC

and nothing has changed now that he’s onboard.

As a previous business owner, Dave always enjoyed business development, which covers all

facets of business, from the hunt for opportunities to contractual agreements to continuing

customer support. He thinks you will find an excellent organization behind any successful

business person, and that ARINC is one of the best.

Dave joined the working world at a young age. His father owned a garbage business when

Dave was a child, so throwing trash was his first job, followed by running heavy equipment

(977 Cat and a D-8 Cat and Pan) at the landfill at the age of 14/15.

His memorable professional accomplishment, in addition to running a family business, was

working in the 1990s for the new company AirCell as the number-two hire. Dave was part of

the team that succeeded with the David-and-Goliath battle at the FCC, winning approval for

AirCell’s cellular technology for aviation.

Dave got into the aviation industry as a commercial pilot, and though flying has always

been a love of his, now it’s mostly in the back of a plane. He has always been active in

the church, mostly involved in music ministries. Golf is another one of his passions.

He was born and raised in York, Pennsylvania, where today his mother, two sisters, and a

brother still live. Dave and his wife, Alexandra, have six-year-old twins—a boy and a girl—

who keep the family busy with sports activities and school. A personal accomplishment was

raising a stepson, who graduated from the University of Colorado last year with a Masters

in Aerospace Engineering and a minor in Electrical Engineering. During his time in college,

his stepson spent his spare time working in youth ministries as a worship leader playing the

guitar and piano.

David Zeigler Business Development Director, Commercial Aviation Solutions,

tel: +1 410.266.2249 [email protected]

Voice & Data CommunicationsGLOBALink


Reintroducing AeroConnxTM eEnabled Aircraft Solutions and ARINC GateFusionSM

In 1979, a new technology, the Aircraft Communications Addressing and Reporting System

(ACARS®), was developed, which revolutionized aircraft communications. Since that time,

airlines have continued to find new ways to use ACARS, including VHF Data Link Mode 2

(VDL Mode 2). Today, in any given month, well over 20 gigabytes of airline operational data

are transferred over ACARS data link networks for the entire airline industry. ARINC has been

an industry leader in making this happen.

Fast-forwarding to 2011, we can see a revolutionary occurrence in the introduction

of eEnabled Aircraft, which are aircraft with electronic flight bags (EFBs) installed. In

an eEnabled Aircraft, potentially gigabytes of information—including chart updates,

maintenance logs, and flight operational quality assurance (FOQA) data—are transferred

from just a single aircraft in a given month! This enormous transfer of data is a result of the

installation of EFB systems onto aircraft and the use of broadband gatelink communications.

Once again ARINC is leading the industry with its AeroConnxTM EFB products and services

and ARINC GateFusionSM gatelink services.

An EFB, in layman’s terms, is simply a PC installed on the aircraft, typically in the flight deck.

However, to be cost-effective the total solution requires complete end-to-end engineering

integration of the aircraft eEnabled network, data link communications, and ground IT

systems. Appropriate and cost-effective implementation of a data link solution to connect

the aircraft to the ground needs to be the focal point of any EFB solution. This is where

ARINC’s history of industry leadership as a global data link service provider delivers the

perfect complement for our AeroConnx eEnabled solutions.

With AeroConnx eEnabled solutions, ARINC provides the full complement of products and

services to implement an end-to-end EFB program. ARINC’s systems engineering and

knowledge of the industry enables defining a cost-effective and best-of-industry solution that

is designed to meet the airline’s business needs and operational requirements. Included in

the final solution are third-party hardware components, ARINC-developed EFB applications,

integrated third-party EFB applications, ARINC’s EFB Content Delivery Management System

and other ground applications, ARINC’s AeroSync Air and Ground Data Communication

Management Services, and ARINC’s GLOBALinkSM data link network services.

Robert Lentz Senior Manager,, Aviation Solutions, ARINC


2

Contact the Author


3

Reintroducing AeroConnxTM eEnabled Aircraft Solutions and ARINC GateFusionSM—Continued

ACARS, VDL Mode 2, and Iridium satellite are not viable options for the larger volumes

of data traffic that will eventually be expected with an eEnabled Aircraft solution. ARINC

GateFusion is the service offering the broadband data link service commonly known in the

industry as Gatelink. Currently, GateFusion is deployed to support 802.11 (Wi-Fi) wireless

infrastructure installations at airports around the world. GateFusion’s Wi-Fi service is built

to meet the standards of AEEC ARINC Specification 822-1. A unique feature of GateFusion

is the Data Delivery Service, which allows for scheduled and optimized content delivery in

order to minimize the ground network bandwidth requirements. AeroSync Communication

Management has the ability to use airline-policy-based algorithms to select the most

appropriate data link medium for the content. Large transactions will be directed over a

broadband service such as GateFusion, while smaller transactions can be directed over

ACARS or Iridium.

ARINC has been developing and expanding its eEnabled products and services since the

early 2000s. In 2003, ARINC deployed the first Class 2 EFB solution integrated with ACARS.

In 2006, ARINC successfully deployed a graphical weather EFB application that uses VDL

Mode 2. In 2010, six years of effort with Cathay Pacific culminated in the deployment of

a complete end-to-end solution consisting of all products and services described in this

article. This solution is currently operational on a B777-300 and has met all objectives. In

2011, Cathay will begin deploying the demonstrated functionality and more to the rest of its

fleet. ARINC has extended its industry leadership into the next revolution involving aviation

communication.


ARINC OpCenterSM FANS Management

The Future Air Navigation System (FANS) allows air traffic services (ATS) facilities on the

ground to deliver bit-oriented messages to aircraft using the character-oriented ARINC 622

protocol. FANS applications are defined in RTCA DO-258 and include controller-pilot data

link communications (CPDLC) and automatic dependant surveillance (ADS).

FANS CPDLC allows the exchange of standard ATS clearances and instructions via data

link (ACARS® messages) instead of voice. CPDLC messages are preformatted and use

a standard phraseology defined to avoid any misunderstanding between the pilot and

the controller. A reduced risk of misunderstanding and a reduction of pilot and controller

workload are some of the benefits of FANS CPDLC.

ADS allows air traffic control (ATC) centers to automatically receive position reports,

headings and other information used for aircraft tracking, positioning and trajectory

prediction. The ground system establishes a contract with the aircraft which then

provides position reports on a regular basis.

FANS messages are sent as ACARS messages but since the message content is bit-oriented

a regular ACARS host system is not able to read them. ARINC OpCenterSM can be configured

to decode all DO-258 encoded messages (uplinks and downlinks) forwarded to the

customer’s OpCenter. FANS message decoding is available for all OpCenter customers.

In addition to decoding the ADS downlinks resulting from ADS contracts established by

ATC centers and copied to the customer’s OpCenter site, Pro OpCenter customers can

be configured for FANS Management graphical user interface that allows the customer to

establish an ADS contract with their own aircraft. The user can establish/cancel periodic,

event, current position, or emergency ADS contracts.

Decoded ADS position reports can then be forwarded to an aircraft situation display (ASD)

such as ARINC WebASDSM to provide enhanced situational awareness.

Yuri Maslov Senior Program Manager, GLOBALink Information Management, ARINC


In-Flight ApplicationsGLOBALink

4

Contact the Author


Cherlene Chua Senior Staff Analyst, Airlines Programs, ARINC

tel: +65 6224 4152 [email protected]

5

ARINC in Asia

Enhancing Flight Safety in Asia

ARINC Asia Pacific Division (APD) continues to focus on enhancing data link safety services

with our VHF data link expansion in Asia Pacific as well as provide data link training to our

Asian customers.

As part of the ARINC APD ACARS® training program for our Asian customers, ARINC APD

conducted the 7th Airline Data Link Communications and Applications Training at ARINC’s

headquarters in Annapolis in October 2010. Among the 2010 class participants we had

seven different Asia Pacific carriers who joined the training, namely from China Southern,

Hainan Airlines, Okay Airways, Vietnam Airlines, Air New Zealand, V-Australia, and Skymark

Airlines. Through this training, ARINC covers topics on avionics system architecture,

protocols, input and output interfaces, and the details and functions of the individual

units that make up the ACARS data link system. ARINC APD is committed to providing

ACARS training annually. Any interested participants may contact Cherlene Chua for early

registration.

In the last quarter in 2010, ARINC added three new ground stations to expand the

GLOBALinkSM network in South Korea. The deployment involved providing GLOBALink/VHF

coverage at Cheongju International and Yeosu International Airports. Besides offering

VHF coverage at new sites, ARINC is committed to improving existing sites by deploying

auxiliary ground stations to enhance existing GLOBALink coverage at Gimpo International

Airport. The station deployments were accomplished with the support of two ARINC Asia

Pacific GLOBALink partners, South Korea’s AirMedia, and Aeronautical Radio of Thailand

(AEROTHAI). The expansion brings ARINC’s South Korean network to a total of eleven

ground stations. Hence, airlines arriving and departing from South Korea will benefit from

more accurate reporting of aircraft movements and status, while congestion on voice radio

channels can be reduced.

Contact the Author


6

ARINC in Asia

Enhancing Flight Safety in Asia—Continued

2010 Airline Data Link Communications and Applications Training participants from the Asia Pacific region.

The new year has begun with greater focus on expanding GLOBALink Asia coverage and

ARINC has successfully deployed two more ground stations in Malaysia, namely in Miri

and Langkawi. The station deployments were accomplished with the support of two ARINC

Asia Pacific GLOBALink partners, Malaysia’s Telekom Malaysia, and Aeronautical Radio of

Thailand (AEROTHAI). With this expansion in Malaysia, ARINC has coverage now at six sites

in Malaysia, namely Kota Kinabalu, Kuching, Kuala Lumpur, Miri, Langkawi and Penang.

ARINC APD’s commitment to customer training in data link, VHF expansion, HFDL enhanced

reliability and additional HF voice capability in this region will enhance in-flight data/voice

transfer and communications between airline operations centers and flight decks as well

as among carriers.


ARINC in Europe, the Middle East, and Africa

Link2000+ In Full Swing

Data link communications will change dramatically in Europe over the next two years as

VDL Mode 2 becomes the preferred method for controller-pilot data link communications

(CPDLC). ARINC is taking an active role in ensuring that the benefits of the new technology

are maximized for the air transport industry.

The framework for the adoption of VDL Mode 2 for CPDLC was published in January 2009

by the European Commission (EC) in the form of a Data Link Services Implementing Rule

(DLS IR). The first milestone of this legislature has already taken effect as of 1 January

2011, which requires all new aircraft operating above flight level (FL) 285 to be delivered

with a compliant system. The next critical date is 7 February 2013, by which time the ten

largest European Air Navigation Service Providers (ANSPs) will need to have implemented

an operational compliant ground system. It is a tall order.

To put this Implementing Rule in perspective, to this date only one operational ATN CPDLC

service has been available anywhere in the world–over the airspace of Maastricht Upper

Area Control Center (UACC). In 2003 ARINC deployed a VDL Mode 2 network for Maastricht

UACC in a record time of six months and full CPDLC operations began in 2004.

In contrast, over the next two years ARINC will have to deploy VDL Mode 2 coverage for

ten ANSPs in Europe, which will require the upgrade or installation of an estimated 50 VHF

ground stations across the continent, along with the required ATN backbone infrastructure.

Adding to the challenge will be the fact that no two ANSPs are alike in terms of local

requirements, capabilities, and network infrastructure. In this context the role of ARINC

will evolve from a traditional data link service provider to an industry partner with years

of experience and a history of quality customer support.

One example of this evolved approach is the partnership between ARINC and ENAV, the

ANSP in Italy. ARINC has been working closely with ENAV since 2007 for the development

and implementation of a purpose-built Italian VDL Mode 2 CPDLC network, called LinkIT.

The network is currently being deployed and it incorporates ARINC’s core ATN routers as

well as ARINC’s software for the VHF ground stations.

7

Yanko Videv Technical Support Manager, Aviation Solutions, EMEA, ARINC

tel: +44 1293 64 1368 [email protected]

Contact the Author


GLOBALink/HFDL

Solar Cycle 23/24: A Tale of Two Suns

I Like the changes of 4 seasons on Earth every year, our sun experiences a cycle of activity

that typically lasts 11 years. During the years of maximum activity, the sun emits X-rays from

sunspots, highly charged plasma from flares and Coronal Mass Ejections (CME) and intense

solar winds from coronal holes.

HFDL mostly relies on bouncing signals off the ionosphere (that invisible layer of charged

particles from 37km-375km) to deliver ACARS® messages farther than line-of-sight

communications media. When the sun is not as active during the lowest point of the cycle,

signal reflectivity can be more challenging. So solar activity is directly linked to the HF

environment.

Solar Cycle 23 definitely provided that full range of environments for the HF data link

team to adapt and overcome. The cycle marked some of the most violent solar eruptions

and ended with an extended quiet period (~4 years) that has never been experienced in

recorded history. During this tumultuous solar cycle, the HFDL team has been able to keep

the data flowing to aircraft time and time again.

Typically a solar cycle lasts 11 years. Cycle 23 lasted an extra 2 years past its expected

end. The HFDL team has gained an extended solar cycles’ experience for adaptive frequency

management, coverage gaps and special propagation conditions. Solar cycle 24 has

already begun and the environment is rife with activity, injecting much needed energy into

the ionosphere. The HFDL team is expecting about 7 years of optimal signal propagation

conditions.

The HF data link team has developed

and continues to evolve the adaptive

frequency management system and

the propagation models so the most

optimum frequencies are in use at all 15

stations world-wide. Our models continue

to evolve as the earth’s magnetic field

shifts about 40 miles per year and

aircraft traffic patterns go through

seasonal changes and operational

evolutions.

Combine our efforts on the ground with

the advanced avionics software in the

aircraft radio and you have unsurpassed

dependability for HF communications.

8

John Patterson Principal Engineer, Customer Services, ARINC



Contact the Author

Photo courtesy of NASA/SDO and the AIA, EVE, and HMI science teams.


GLOBALink/Satellite

Ancillary Terrestrial Component (ATC) Concerns Increase

What is the ATC acronym that has been communicated throughout the aeronautical industry

in a mostly negative light over the past number of years? ATC is a terrestrial-based mobile

telecommunications capability that is integrated within a mobile L-band satellite system.

It will share the same L-band frequencies as Inmarsat, Iridium and the Global Positioning

System (GPS). The system is designed to combine wireless ground services with airborne

satellite communications. Customers with ATC mobile devices can have access to an

enhanced fourth generation (4G) wireless broadband network no matter where they travel.

The ATC service development is not new, as the Federal Communications Commission (FCC)

amended its rules back in 2003 to allow certain mobile satellite service operators to offer

this solution. These rules were amended because the FCC believes that ATC operation would

increase network capacity and provide more reliable services including areas where current

ground based coverage has not been optimal or existent, plus ATC is a more efficient use

of radio frequency spectrum. With that said, LightSquared, along with its diverse group of

partners, is the company which plans to deploy the ATC network in North America. Initial

service offerings could commence the second half of 2011, with more than 90% of the

American public covered by the end of 2015.

The new combined terrestrial and satellite service offering sounds reasonable in concept

and could include many tangible benefits, however, there have been some legitimate

concerns raised about interference across users of GPS and aircraft operators that are

equipped with either Inmarsat or Iridium satellite communication technologies. The U.S.

government in particular has expressed concerns about mobile phone users operating on the

new service, which could be interfering with both GPS signals for military/non-military users

and also aircraft that are in proximity to the powerful ground base transceiver stations.

Potential service interference or degradation issues as a result of the ATC deployment

are now under investigation as Inmarsat, contracted entities, and industry councils are

evaluating and monitoring the effects of these transmissions. Ultimately, bringing greater

visibility to this issue in the marketplace will help ensure that our customers are protected

from any detrimental consequences once the new ATC broadband service is deployed.

We will continue to keep you updated on the progress of this initiative.

Tom McCullough Business Manager, Satellite Services, ARINC



9

Contact the Author


GLOBALink/Iridium

FANS Over Iridium (FOI) and Iridium NEXT

In previous issues, we discussed the FANS over Iridium (FOI) operational trials conducted by the FAA-sponsored Performance-Based Operations Aviation Rulemaking Committee (PARC) Communications Working Group (CWG). The PARC CWG has recommended to the FAA to remove restrictions on the use of Iridium in FANS 1/A operations. The recommendations report substantiated that FOI operations can meet the Required Communication Performance (RCP) 240 and Required Surveillance Performance (RSP) 180 specifications for reduced separations. The PARC CWG hopes for a favorable response from the FAA to allow FOI aircraft to be eligible for reduced 30 and 50 NM longitudinal and 30 NM lateral separations implemented throughout Asia and Pacific Regions, and reduced 25 NM lateral and 5-minute longitudinal separations being planned in the North Atlantic Region.

In order to provide long-term continuity of FOI and other services, Iridium has recently announced that they will build and launch a replacement constellation of satellites called Iridium NEXT. Current installations of Iridium aeronautical avionics will be fully compatible with these new satellites.

Iridium NEXT will expand Iridium’s capability to meet rapidly expanding demand for global mobile aeronautical communications. Anticipated to begin launching in 2015, Iridium NEXT will maintain the existing Iridium constellation architecture of 66 cross-linked satellite low-Earth orbiting (LEO) covering 100 percent of the globe. Iridium NEXT will substantially enhance and extend Iridium mobile communications services, delivering:

• Higherdataspeeds • Powerfulnewservicesanddevices • AdvantagesofIPtechnology • Backwardcompatibilitywithcurrent handsets, devices and applications, i.e., FANS Over Iridium (FOI) avionics

Iridium has completed major milestones in its comprehensive plan for funding, building and deploying Iridium NEXT. Specifically, prime contractor Thales Alenia Space has made significant progress around the design of the Iridium NEXT constellation of satellites. Coface, France’s export credit agency (ECA), led the financing of Iridium NEXT by securing nine banks to provide up to $1.8 billion in a credit facility to fund the project.

ARINC will keep readers up to date on the progress of launching the Iridium NEXT constellation of satellites in future issues.

Bob Thompson Senior Director, Satellite Services, ARINC



10

2009-Q1 System Requirements Review

2010-Jun “Authorization to proceed” from Coface; Prime Contractor. Thales Alenia Space begins development phase Iridium NEXT

2010-Oct Iridium successfully closes financing; Full Scale System Development Contract with Thales Alenia Space effective

2011—2014 Development and construction of Iridium NEXT satellites

2011-Q2 System Preliminary Design Review

2012-Q3 System Critical Design Review

2013-Q3—2013-Q4 System Development and Satellite Vehicle Qualification

2015-Q1 Iridium NEXT begins launching

2016-Q4 Launch campaign complete

2017 Iridium NEXT fully deployed

Iridium NEXT Key Milestones

Contact the Author


GLOBALink Radio Installation & Maintenance

Narrowbanding

There is a lot of talk in the ground radio world about Narrowbanding. If you operate radios in the 450 MHz band, you should become well acquainted with this topic.

In 2004, the U.S. Federal Communications Commission (FCC) mandated that all radios operating in the 150 to 174 MHz and the 421 to 512 MHz frequency ranges will need to operate within the 12.5 kHz channels, as opposed to the 25 kHz channel used today. This mandate is set to take effect on January 1, 2013.

The main issue being encountered today is that the current 25 kHz spectrum is saturated. Because of this saturation, it is becoming increasingly difficult to get a license in those bands. If you are able to secure a license, the chance of encountering interference is very high. By requiring a change in the channel spacing, a new spectrum will open up allowing for more licenses to be issued, and will also result in clearing up inherent interference problems.

ARINC Radio Technology Solutions has been staying on top of the regulations and is working with our internal and external customers to ensure compliance. From radio programming, configuration changes, and license modification, RTS is ready to assist customers in attaining compliance. We would be happy to discuss your current equipment and how this new mandate will affect you. Please feel free to contact us for a free consultation on meeting your Narrowbanding transition needs.

John Monto Director, Radio Technology Solutions, ARINC


GLOBALinkRadio Installation & Maintenance

11

Narrowbanding Questions to Ask:

• Whatareradiocustomerrequirementstoensurecompliancewiththe new regulation? To ensure you are compliant, your radios and repeater must be set to operate within the 12.5 kHz channel setting.

• Arecurrentradioscapableofmeetingthisnewrequirement? While most radios in operation today are capable of meeting the requirement, they must be configured to do so. Some older radios may not have this capability and will require replacement.

• Whatfrequencylicensemodificationsarerequired?

The FCC license must be updated as well to reflect the Narrowband spectrum change.

Contact the Author


Technotalk

VDL Mode 2: Expanding the Capacity to Meet the Demands of the Future…

Background—Back in the late 1990s many within the industry expected the introduction of ARINC’s VDL Mode 2 service to quickly replace Classic ACARS® which was perceived to be slow and was thought to be reaching its capacity limits.

In hindsight, with a decade behind us, that initial growth in VDL usage was much slower than anyone had expected due to a number of external factors. At the same time, the growth in Classic ACARS usage continued, nearly doubling from 18 to the current 32 million messages per month.

However, in the past few years, we arrived at a point where the VDL Mode 2 service is gaining significant traction. Today, most new aircraft are delivered with VDL Mode 2 as a standard feature and other aircraft have been retrofitted to VDL Mode 2 capability. As a result, ARINC has 2,600 aircraft actively using our 369 stations that offer VDL service. They send approximately 7 million messages per month (or about 20% of our total VHF traffic). With the success of EUROCONTROL’S’s Link 2000+ Programme, the industry is moving forward with firm plans for greater adoption including SESAR (Single European Sky) in Europe and the FAA’s NEXCOMM program in the USA. These programs all require VDL Mode 2 as the communications backbone.

Current VDL Mode 2 Status—Currently all AOC and ATS applications are carried on a single VDL Mode 2 VHF channel of 136.975 MHz which is the world-wide Common Signaling Channel (CSC) that is shared by all DSPs that offer service. With VDL Mode 2 channel efficiencies of more than 10 times greater than Classic ACARS, we have room for significant growth. Nevertheless, in order to meet projected customer capacity requirements and CAA performance expectations in the future, it is now time to plan for expanding the capacity of the VDL service. The first step is to ensure the correct protocols and frequency management capabilities are included in the ground and aircraft avionics.

With Classic ACARS, the distribution of ACARS traffic is relatively simple. Protocols are used to move aircraft from the DSP base frequency to a group of alternate frequencies. It is the Data Link Service Provider’s (DSP) responsibility to monitor traffic levels on the ACARS base and alternate frequencies or channels. If the traffic on a particular channel becomes congested, the DSP sends an uplink “autotune” command to the aircraft, and the Communications Management Unit (CMU) commands the VHF radio to switch to the assigned ACARS frequency. The aircraft CMU then sets up a connection on the new channel. If communication cannot be established or is lost, the ACARS CMU always returns to the DSP known “base” frequency and re-establishes the connection.

Steve Leger, Director, Testing and Support Services, ARINC


12

Contact the Author


Technotalk

VDL Mode 2: Expanding the Capacity to Meet the Demands of the Future…—Continued

VDL Mode 2 Frequency Management—VDL Mode 2 Frequency Management is defined in AEEC Specification 631 and is considerably more complicated than Classic ACARS. Instead of a single “autotune” command there are three separate VDL Multi-Frequency functions. One reason for the added complexity is that with VDL Mode 2, the aircraft establishes a logical connection with a particular VDL station. As mentioned previously all aircraft know enough to look on the VDL Common Signaling Channel (CSC) to make their initial VDL connection. After the initial connection, the aircraft follows a series of unique VDL rules (described below) that determine which VDL station and frequencies the aircraft will use.

Frequency Support List (FSL)—Periodically, on the CSC, the DSP will uplink a list of available VDL Mode 2 stations and associated frequencies. Normally this list will be included in the Ground Station Information Frame (GSIF) which is a broadcasted uplink, like an ACARS squitter, that provides DSP identification and information about available services. The aircraft receives the FSL list, and depending upon criteria such as the phase-of-flight, the CMU will randomly choose one of the VDL frequencies from the list, retune the radio, and attempt to establish a connection with the station.

Ground-Initiated Handoff (GIHO)—Based on criteria such as falling signal quality, the ground DSP may want the aircraft to switch its logical connection from one VDL ground station to another. The GIHO command is an uplink that requests the aircraft CMU to handoff from its existing station to a new VDL remote ground station (RGS) that is sending the command. The command is sent and the aircraft responds by handing off to the new station.

Ground-Requested, Air-Initiated Handoff (GRAIHO)—Under certain conditions, the DSP’s ground station may want an aircraft to disconnect from its current station and handoff to a new VDL ground station which may be operating on a different VDL frequency. The GRAIHO command provides this function. Upon receipt of the GRAIHO, the CMU is required to tune to the new VDL frequency, execute a handoff to the new station, and establish a new end-to-end connection.

In preparation for VDL Multi-Frequency operations, ARINC has been supporting the industry in several ways.

ASRI VDL Mode 2 Spectrum Planning for North America—First, Aviation Spectrum Resources Incorporated (ASRI), the agency that manages and assigns VHF Frequency Licenses for the Aeronautical Spectrum within the USA, has created a special working group within their committee of airline users. ARINC serves as the co-chair for this committee and is providing RF propagation analysis and test data to support the development of a VDL

13


Technotalk

VDL Mode 2: Expanding the Capacity to Meet the Demands of the Future…—Continued

Mode 2 channel assignment plan that will both maximize VDL Mode 2 spectrum efficiency

and capacity and also minimize the possibility of interference between VDL Mode 2 and

other communications, such as Voice and Classic ACARS, that share this VHF band.

ARINC VDL Mode 2 Multi-Frequency Test Program—ARINC has also developed a

dedicated VDL Mode 2 Multi-Frequency Test Program for industry use. This includes a

detailed and comprehensive test plan and procedures document that provides 43 unique

test cases and pass/fail criteria. This documentation suite has been distributed to most

avionics and aircraft manufacturers and is available to the industry. To complement the

documentation, ARINC has also developed a dedicated test facility which is co-located in

the VDL Interoperability test facility in Annapolis, Maryland. The test facility includes a suite

of field-ready, ground stations and numerous VDL transceivers so that many scenarios can

be tested and assessed.

As a result, VDL Multi-Frequency Testing has been conducted on approximately one half

of the dominant avionics products in the field. As is expected with the introduction of a

significant technical advancement, initial testing has identified a considerable number

of issues, both “bugs” and areas where there were differences in the interpretation of

the industry standards. In addition to verifying proper VDL protocol, the testing provides

considerable focus on continued connectivity and graceful recovery during unexpected

events and faults, such as late or missing VDL commands.

Due to the complex nature of the multi-frequency protocols this is not unexpected, and

ARINC and the avionics manufacturers continue to work together in reaching full DSP

and avionics compatibility. From an engineering viewpoint, finding and correcting

problems during the early, pre-deployment phases provides sufficient justification for

the test program and insures trouble-free VDL performance for our customers.

Conclusions—With many developing plans for VDL communications, ARINC, along

with industry partners is moving forward to develop the means to support VDL Mode 2

multi-frequency capabilities. Moving past the VDL CSC will require software updates both

in the aircraft CMUs as well as DSP infrastructure. ARINC is actively involved in software

development, avionics interoperability testing, and industry committees to insure that the

GLOBALink/VDL service is ready to provide exceptional performance and capacity for

today and the future.

14


VHF

A Project Engineer’s Perspective

“Has it really been 10 years?” That was the question I asked myself when reflecting on

the very first operational VDL Mode 2 ACARS® over AVLC (AOA) ground station that

ARINC deployed. I’ll admit, the realization of how quickly time passes gave me pause.

In March of 2001, ARINC certified operational status of its VHF Digital Link Mode 2

(VDLM2) AOA system on six bilingual ground stations—supporting AOA and Plain old

ACARS (POA)—in North America. What followed was a large scale commitment to VDL

Mode 2 enhancement and deployments around the world that continues today.

When I reflect back to 2000 and 2001 I realize it was certainly an exciting time to be part

of the GLOBALinkSM/VHF team. While we were launching the AOA service we were also

busy deploying a VDL Aeronautical Telecommunications Network (ATN) ground network in

Europe to support the trials under the Preliminary EUROCONTROL Test of Air/Ground Data

Link, Phase II extended (also known as PETAL IIe).

Later in 2002, ATN trials expanded to support the FAA for controller-pilot data link

communications (CPDLC) Build 1 in Miami, Florida airspace. Our commitment to ATN

continues today, as PETAL IIe materialized into what we now know as our LINK 2K ATN

operational network in Europe. Currently, ARINC operates thirteen VHF ATN ground

stations throughout the region.

But, the large scale and rapid deployment of our VDL Mode 2 service these past 10

years is nothing short of impressive. Today we have over 300 VDL ground stations in the

continental United States supporting all 65 FAA Tower Data Link System (TDLSSM) airports.

Worldwide we are at 367 operational VDL Mode 2 ground stations in 19 countries. Later

this year, we will expand VDL to more new countries as well as adding to our already

robust network in the existing countries. That will allow for new destinations with VDL

Mode 2 ground coverage and increased availability of our existing en-route coverage.

At present ARINC’s VDL Mode 2 service supports more than 2,600 aircraft and transfers

over 7 million messages per month. In conjunction with our VDL Mode 2 service, ARINC

still provides our legacy analog POA service and our total VHF network (VDL and POA)

supports close to 10,000 aircraft and excess in 33 million messages per month.

A very busy 10 years past with growth that promises an even busier future!

I look forward to writing to all of you again while asking myself “Has it really been

20 years?”

15

John Christian Sr. Manager Data Link Implementation, Aviation Solutions, ARINC


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