Datalink

The value of aircraft datalink communications is proving itself on a daily basis, from the traditional aircraft communications addressing and reporting system (ACARS) that transmits specific aircraft parameter data from the plane to the ground, to recently introduced gatelink-type services that allow flight crews to take advantage of cell phone networks.

And the worldwide datalink market is likely the erupt in the coming years, thanks to ITT’s initial $207 million, three-year contract award last year to develop and deploy FAA’s Automatic Dependent Surveillance-Broadcast (ADS-B) ground infrastructure, and Europe’s impending Link 2000+ implementation.

“These things will open up the potential for the industry to develop new applications that can be used by airlines to perform operations in airspace that will make it more efficient for them to operate,” said Chuck Manberg, a staff engineer at ACSS, the Thales and L-3 Communications joint venture.

More specifically, Manberg said, ACSS’s “SafeRoute” merging and spacing system used by UPS provides a good example of this trend (Avionics, June 2007, pg. 32).

“Datalink that provides information to the ground can also transmit and receive data aircraft to aircraft,” he said.

“It could help you space aircraft more efficiently when landing at an airport because you don’t have to be vectored by ATC. You can use the data more efficiently to merge aircraft coming into airports, which could be particularly valuable to UPS in Louisville, where 100 aircraft come in over a two- to three-hour period.”

“SafeRoute” was certificated last year. UPS is outfitting about 100 Boeing 757s and 767s with the capability — introducing it first for West Coast arrivals into the cargo carrier’s Louisville, Ky., hub.

For avionics engineers, envisioning new datalink-driven capabilities like “SafeRoute” is easier than maneuvering through FAA’s approval process.

“What’s at issue here is we’re implementing these applications with an infrastructure that is just beginning to come into play,” Manberg said.

“The challenge is to take technology that is evolving today and put it where it can be used as a benefit to the airlines, and implement it in such a fashion that we can certificate it with the FAA.

“No standards existed for the application that we were defining. We had to work closely with the FAA on how the equipment is used operationally.”

Because it was cost prohibitive to modify UPS’s existing flight deck systems to display “SafeRoute” data, information generated by the program will be presented on a Class 3 electronic flight bag (EFB) from Boeing, which is manufactured by Astronautics Corp. of America. ACSS said it plans to introduce an iteration of “SafeRoute” for less-costly Class 2 EFBs later this year.

Link 2000+

Outside of the United States, the worldwide datalink infrastructure is expected to take a great leap forward with the impending Implementation Rule for the European Link 2000+ system.

The European Commission is expected to approve the Implementing Rule in July, which will kick off a mandate for forward fit of datalink capability in 2011 and retrofit into all other aircraft in 2015.

“They want to have all controller-to-pilot communications go through a VDL (VHF digital link) network,” said Didier Perrin, senior director of air transport marketing for Rockwell Collins.

“It will make the controller less involved in the transaction, and as a result optimize the way they work. It is the first technical implementation of SESAR (the Single European Sky ATM Research Program), which is planned to triple traffic in European airspace by 2020 with the same level of safety.”

European Link 2000+ compliance will require use of a communications management unit (CMU) loaded with Level C software capable of handling controller-to-pilot datalink communications. Perrin said the job could be done with Level B software, but use of Level C in the CMU removes the requirement for pilot read-back. Information will be presented on a dedicated display.

Eurocontrol and FAA have had a series of coordination meetings, and both agreed to harmonize their approach. Link 2000+ will begin its mandate and implementation five years before FAA’s planned System Wide Information Management (SWIM) program Segment 2 in 2016. FAA has agreed to provide services and accommodate Link 2000+ and FANS 1/A equipped aircraft. The definition of accommodation and what services to be offered by FAA are still under discussion.

Sub Channels

Because of the high cost of satellite-based UHF datalink, airlines and business jet operators are looking at a number of sub channels that can perform similar roles at reduced cost. The re-launched Iridium constellation is one of those systems gaining increased exposure.

“It has the potential to be qualified and approved for safety services, all the communications that have to do with ATC,” said Perrin. “The main advantage for airlines is a reduction in communications cost. I’m looking for an operational plan to be done by early next year.”

Continental Airlines and Colombian carrier Avianca have agreed to direct their ACARS service from SITA through the Iridium network, said Philip Clinch, SITA vice president of aircraft communications and messaging.

“We have seen a few customers very interested in equipping their aircraft with that because the FAA has increased requirements for voice capability to keep in touch when in some remote locations … and also for datalink,” Clinch said.

Airlines and other users also want access to sub channels like mobile/cellular (GSM, GPRS, UMTS) networks, Wi-Fi, WiMax and non-satcom broadband as a way to avoid UHF communications expense, particularly for ground operations. Such solutions, however, will require the integration of the aircraft with an airline’s IT network.

“A lot of AOC (Airline Operations Center) communications that are transmitted via ACARS can be transferred to the ground,” Perrin said.

“To send this data, aircraft CMUs have to be able to talk to these new sub networks. Now the technology is there for the airlines to use it.”

Teledyne Controls, El Segundo, Calif., is one of the companies “involved deeply” in developing gatelink-type applications, according to Teledyne Vice President of Technology Jody Glasser.

“One of the things we’re doing is commercial wireless ground link up to ACARS units on single-aisle airplanes initially,” Glasser said. “Our box acts like an ARINC 741 SDU [satellite data unit] or HF datalink without requiring a change to the ACARS unit. For airlines that are ACARS users but fly to places without good VHF coverage, they can leverage an investment they’ve already made.”

Airlines also are exploring development of IP-based protocols for datalink as another way to reduce communications cost.

“IP standards development is in its early development phase, however, and we expect implementation to occur no earlier than 2015,” Perrin said.

“The largest challenge is mobility management since the aircraft fly very fast. The industry has made ACARS mobility work with IP V.6 but it has taken a long time.

“IP will require new datalink software developments and potentially new platform developments, especially federated architectures. However, IP should harmonize the various ATC datalink systems: FANS 1/A, Link 2000+ and ARINC 623,” Perrin said.

Data security will be of paramount concern for airlines using any of these sub channels for communications.

“The ultimate goal of airlines is to make airplanes a node on their network, so there’s a challenge related to information security and network security. There are well-accepted means to solve these problems with digital certificates but there are issues of how you do that in various locations with shared and private infrastructure,” Glasser said.

Bandwidth Issues

The number of applications taking advantage of datalink communications is growing exponentially, bringing enhanced safety to airline operations while reducing the workload for pilots and controllers. That popularity, however, is likely to lead to digital bottlenecks as myriad applications compete for the same bandwidth.

“Users are always trying to squeeze more information through with various applications,” said Manberg. “For example, the datalink we’re using is also shared with TCAS [traffic alert collision avoidance system], which will interrogate the transponder and use the data in its collision algorithm, and with secondary surveillance radar, which interrogates aircraft in their area and provides that information to ATC. Hence, that’s why we have some bandwidth issues.”

One solution is a reduction in the number of interrogations, which could be facilitated by ADS-B. Such “hybrid surveillance” would rely primarily on ADS-B positioning data and only interrogate transponders once aircraft came within a certain proximity of each another.

Datalink constriction could even lead to a competition for bandwidth within individual aircraft, Glasser said. “Once we start having these capabilities we’ll get into competition for them between the flight deck, the cabin crew and passengers. There could be a competition over how bandwidth gets allocated between flight ops and marketing. Who’s it here to primarily service and who pays for it? Two hundred people sharing a megabyte might not be a good user experience.”

Complaints are likely to leavened, though, if new datalink capabilities can alleviate ATC congestion, particularly in places like the crowded airspace around New York. “Not only are vendors looking at ways to help solve that problem, the FAA is looking at ways,” Manberg said. “We’ll continue to push the technology to go down the path of making airspace as efficient as possible by using datalink as part of the ATC infrastructure.”

Market Moves

Following are some recent developments announced by datalink service providers and equipment manufacturers.

— SITA in June said it is expanding its aircraft communications service to short-haul aircraft by using the Iridium satellite network. The expansion was announced to 30 airlines during the May meeting of the SITA AIRCOM User Group in Madrid, and three airlines had committed to using the service.

— ARINC, Annapolis, Md., was awarded several datalink contracts and extensions. In May, ARINC said it will provide flight communications for the new Delta Connection regional passenger service operated by Pinnacle Airlines, based in Memphis, Tenn. ARINC will provide its GLOBALink/VHF datalink and Digital Automatic Terminal Information Service (D-ATIS).

ARINC also installed ADATS (ARINC D-ATIS Tower System), an automated broadcast system for D-ATIS messages, at Eglin, Randolph and Elmendorf Air Force bases. The system converts standard D-ATIS text into voice messages for broadcast to aircraft. It also forwards a copy of D-ATIS messages to ARINC’s Air Traffic Services database, where the messages are available for uplink to aircraft equipped with ACARS data link.

In April, Seoul-based Korean Air renewed a communications contract with ARINC, under which ARINC provides a portfolio of AviNet Type B messaging services for the airline. Type B messages are ACARS messages routed between a service provider and an airline or other ground system. In January, Air Berlin signed a similar agreement, agreeing to a three-year service pact.

ARINC in February won a three-year contract from Etihad Airways to deploy a system based on ARINC’s X.400 Message Handling System, which converts airline message protocols to prevailing messaging standards.

— Avidyne, Lincoln, Mass., introduced a two-way datalink transceiver, the MLX770, that delivers datalink graphical weather and two-way text messaging capability for general aviation operations in Europe.

— Avionica, based in Miami, said Continental Airlines in March completed the first ACARS communications in regular commercial passenger service over the Iridium satellite network. The communication was between a Continental satLINK-equipped Boeing 737-800 flying over the Pacific Ocean and the airline’s Houston headquarters.

— In February, Etihad Airways, based in Abu Dhabi, UAE, announced plans to standardize its aircraft communications addressing and reporting system (ACARS) with a system from AviIT, of Dunfermline, U.K.

AviIT implemented its “Archimedes” system, which decodes ACARS message data and presents it in configurable formats to an airline’s ground-based operations staff, and its “Airboard” system, which interfaces with Archimedes to provide information regarding the phase-of-flight and status of ACARS-equipped aircraft.

“Archimedes and Airboard have been specifically designed to exploit the existing technology investment in ACARS by airlines, enabling data to be turned into invaluable management information that helps to reduce flight crew workload and provide flight ops, ground ops and engineering staff with the information needed to minimize delays and reduce costs,” said David Brown, AviIT CEO.

Avionics Magazine’s Product Focus is a monthly feature that examines some of the latest product offerings in different market segments of the avionics industry. It does not represent a comprehensive survey of all companies and products in these markets.

Companies

ACSS www.acssonboard.com

Acra Control www.acracontrol.com

ARINC www.arinc.com

Astronautics Corp. of America www.astronautics.com

Avidyne www.avidyne.com

AviIT www.aviit.com

Avionica, Inc. www.avionica.com

BAE Systems www.baesystems.com

Caledonian Airborne Systems Ltd. www.caledonian-airborne.com

DAC International, Inc. www.dacint.com

Data Bus Products www.databusproducts.com