The Dawn of Datalink

Some valuable services are available now but we urge caution in taking the plunge too soon.

Datalink this, datalink that, hardware, software, service providers, subscriptions, bit charges, message costs. Holy cow, is this beginning to sound sort of familiar?

Datalink is a generic term that has come to represent text and data services delivered into the cockpit. If you think of it as Internet in the sky, youve got the concept.

For a potential buyer, there are three distinct issues involved; the services provided, the link medium and the airborne hardware. Right now, the industry is in its infancy, funded by various groups with differing agendas, not the least of which is the government.

In other words, none of this stuff is resolved to the extent that you can make reliable buying decisions. The best we can do is offer you a point-in-time snapshot of what exists now and where things might be going in the future. Its up to the buyer to sort out how this applies to his or her needs, a daunting task for folks who have lives to lead outside of techno-geekdom.

Info, Lots of It
Sometimes it seems like the world has gone completely over to the Internet. It isn’t an illusion. Data traffic over phone lines is expected to exceed voice calls in a few years. And why not? A page of text is unambiguous and easy to recall and review, while a voice message is flawed. The driving force for datalink is safety and accurate communication.

Say again Center? Did you say 10L or turn left to 010? Voice communication is dramatically limited by several factors. All of the information has to be processed by a pair of ears, usually working in concert. Each message has to be in a serial format, one word after another, in order. Two messages, words or syllables cant arrive at the same time.

It didnt take long for foresighted individuals to see the wisdom of pumping data into the cockpit in a format other than the old 720-channel VHF. Included in the advanced thinking is none other than the FAA, the first to recognize that were running out of communications spectrum and the limitations of voice communications.

Datalink services arent new by any means. The airlines have used ARINC, Inc. services for years at major airports around the world. Flight data, on and off times, route information and routine dispatch information travels between the airlines and aircraft at the speed of a computer, without the need to type in or transmit voice information.

This service is available today to general aviation as well, delivered as text into the Universal Avionics, Honeywell and Collins FMS systems. Thats an option for your new Gulfstream but not the used Bonanza you have your eye on. Still, datalink is available for the little guy now and more is on the way.

The available services fall into a few categories. There are weather updates, traffic services and flight tracking information. There are also e-mail and messaging services to handle both flight-related and non-aviation data.

Weather is probably the most popular and important information to have available in the cockpit. According to ARNAV, provider of WxLink, weather is the single largest contributor to delays and a major factor in aircraft accidents and incidents, thus they see this service as a potential market leader.

The logical step from TCAS would be to put the same traffic information ATC has directly into the cockpit. Then-as long as the system remains functional-you can be watching your own backside. The FAA has inaugurated TIS (Traffic Information System) as an alternative or augmentation to airborne TCAS systems. TIS taps into the FAAs air traffic network and provides status on any tracked targets, information that can be easily datalinked. The data is there for the taking.

The Link
Datalink is a fine idea, but there’s a slight difference between your Internet service provider and an airborne connection. Your telephone cord isn’t that long. Getting data to and from the airplane requires some type of wireless communication.

The easiest is a VHF radio datalink. These are either aviation frequencies-which are in short supply-or a commercial frequency. Several companies are exploring this option.

One is NavRadio Corporation, which, under a NASA grant, has supposedly developed and will manufacture a VHF comm datalink radio that can double as a VHF comm radio. The unit would process weather data and display it on something like an Avidyne FSD or other color display.

We say supposedly because these guys seem to have used their $1.6 million NASA grant to build a prototype and a sketchy Web site but no discernible customer service apparatus. Numerous calls-and we do mean numerous-for additional information werent returned. Are these guys serious? We wonder.

Meanwhile, ARNAV is serious. Its datalink system uses a discrete VHF radio frequency outside of the aviation band. These systems are limited in coverage area to line of sight (although ARNAV has a neat way around this limitation).

The FAA and ARINC are also using HF (high frequency) datalink communications. These frequencies are in the 20 MHz range and operate best over long distances. Theyre great for oceanic communications and while theyre pretty rotten for voice quality, error correction makes them great for data.

How about regular old cellular phone service? Its out there. AirCell, the worlds only provider of low-cost legal airborne cellular-like communications, is betting that their system will be viable.

Because it behaves exactly like an analog cellular system for data transfer, any modem will do. While not fast by Internet standards, its still speedy enough for weather and radar updates as we’ll as text messages.

Another voice and data telephony solution comes from the 800 MHz air-to-ground service providers, such as Teledyne Controls. Their MagnaStar system is a telephone system capable of 2400 baud in a single system or 4800 baud dual. It was designed to access services such as Universal Aviation Weather and other high-end datalink systems.

These systems still rely on specific ground stations and are pricey at around $40,000. Not contenders for little-airplane GA. The same applies to the Satcom systems offered by CalQuest and Honeywell offering global coverage through INMARSAT satellites.

More down to earth-literally-are links through low earth orbit (LEO) satellites. A company called Echo Flight is the first to take advantage of these low power, inexpensive systems. More on that later.

Last, the Mode-S transponder. Mode-S has been proven by the FAA to work efficiently for limited datalink work. But it has serious drawbacks. The data rate is slow and the directional nature of the antenna means youre in contact only as long as the radar antenna is pointed in your direction.

Imagine if your Internet access could connect only every five seconds or so. Given the competition and the fact that GA has turned a cold shoulder to Mode-S, this one may be a loser.

Here and Now
So much for the potential. Whats affordable for light aircraft GA and out there now? We see three possibilities: Echo Flight, ARNAV and AirCell (see sidebar.)

Echo Flight is marketing a portable system called EchoMap which uses the ORBCOMM constellation of LEO satellites to provide datalink. ORBCOMM is the first commercial satellite provider in this arena, with service started in 1996. These 36 satellites, weighing a mere 90 pounds, are ideally suited to data transfer.

The EchoMap system is a hardware and software package costing $1495. You provide a laptop computer and pay some subscription fees and receive essentially five different but integrated functions, including a GPS-based moving map system.

While not as graphically intensive as the Avidyne screens, its still a color map presentation that tells you where you are. EchoMap is highly fee oriented. You have to remember that this isn’t like clearing the Stormscope. When you push an EchoMap button, youre effectively putting a quarter in the meter. For $9.95 per month, a Weather Option subscriber gets a NexRad composite weather overlay, in near real time. You access the radar map information as needed and are charged up to $3.50 a peek. Actually, the charge is proportional to the amount of radar data retrieved.

If the skies are clear and you only want to check out the closest 100 miles of CAVU, you get nicked 40 cents. You can also get a METAR dump of the closed airports, critical information if youre looking for an aerodrome above minimums. Cost: 50 cents a look.

For 19 cents, the EchoMap system can transmit a GPS position to a text pager or a secure Web site. For 40 cents, a ground-based system user can interrogate a subscribers airplane and receive a position report. You can begin to see the potential here. The EchoMap software is even capable of up and downloading e-mail messages for 25 cents, plus a penny a character (brngs bck memry of Western Union msgs).

The hardware side of EchoMap is a GPS receiver with antenna and an ORBCOMM radio system. The ORBCOMM LEOs operate on 137 to 154 MHz, or just above the VHF comm frequencies.

Any 200 MHz Pentium laptop will do, but Echo Flight also is developing its own sunlight-readable display, called the StratoCheetah. With a list price at press time of $4495, we think that Gateway and Dell neednt be worried about competition.

The oldest service provider (since pre-Internet, even) is ARINC, Inc. The industry regulation body, Aeronautical Radio, Inc., has grown into a global provider of information services. ARINC doesnt have its own hardware. Instead, they use onboard communication gear and flight management systems.

The ACARS (Airline Communications Addressing and Reporting System) has been in use at airports internationally but, as noted, is beyond reach of the Cherokee crowd. But stay tuned, because ARINC has joined with ARNAV to combine their services and offer complete coverage from 777 to PA-28.

ARNAV started as a loran manufacturer 27 years ago. The company has morphed from strictly navigation (although their FMS 5000 is a nice unit) into a serious datalink contender. Their efforts kept the skies over Atlanta safe during the 1996 Olympics, when datalink information was used by helicopters to keep out of each others way. This was the proving ground for what could become air traffic management of the future.

The primary product ARNAV offers is WxLink, a service of weather information up-linked over a dedicated VHF radio. The information consists of NexRad information as we’ll as icing and convective data.

Current METARS, AWOS data, AIRMETS, SIGMETS, PIREPS and forecast weather for a radius of 150 miles from the closest facility is sent to the aircraft and displayed for the crew on the large MFD display. The pilot can also call up additional weather information for areas outside the 150-mile area. The ARNAV network offers coverage over perhaps a third of the U.S. and part of Alaska.

Unlike EchoMap or ARINC, ARNAV is a hardware and service provider. They manufacture the display (MFD 5200) and the datalink radio. Theyll sell the datalink radio as an OEM product, too, for all you budding SkyNet service providers out there.

WxLink uses a discrete radio, like the ORBICOMM, except that this is a terrestrial system. Typically, these radio sets need to be within radio range of the ground station for the system to work. However-and this is important-the ARNAV system can use other airborne transceivers as repeaters.

Because the datalink is a line-of-sight VHF radio, any ground-based transmitter range would be limited by the curvature of the Earth. But put an antenna on a 5000-foot mountain and the range is amazing. So, transparent of your own datalink requirements, your WxLink-equipped airplane could assist as a data server for somebody else.

Like the Echo Flight offering, the ARNAV system can provide e-mail to users. In addition to two-way position reporting, ARNAV offers a sophisticated tracking system. On a PC, a dispatcher can track up to 400 properly equipped machines, whether theyre planes, boats or bicycles.

The ARNAV system is scheduled to be fully operational by next year and is priced on a subscription basis of $595 a year, with the first year free with equipment purchase. Other prices and discounts may be available.

Datalink is here, alright, but still in the beta stage. To a large degree, its still funded by government money in the form of AGATE grants.

Unfortunately, the future leaders in this market wont emerge until theyre forced to be commercially viable. Echo Flight and ARNAV are apparently aware of this, with real-world sales efforts to establish beachheads in the marketplace. AirCell, too, is finally off the ground with voice now and data to come.

If you choose to enter the datalink age now, there’s undeniable risk. Youll be betting that the hardware and software will remain functional and that the company selling it will survive. Our guess is that an inevitable shakeout will sink some of these early ventures.

Remember a company in the early 1990s called Radair? They tried to buy air time and resell weather radar, but failed to gain market share and leasing agreements. Result: DOA.

Without a crystal ball, we cant show you the way. Our best advice is to select a service provider with maximum coverage in your flying area. Also pick somebodys service that matches your requirements. Dont pay more for a system that offers icing PIREPS if you stick to VFR skies. At the risk of hurting worthwhile startup competition, if youre an early adopter and you want to reduce the risk of getting stuck with an orphan, our advice is to stick with a company with an established record, such as ARNAV. Echo Flight may be a comer, too, but its too soon to say.

Datalink will be the Internet of the cockpit. Some providers will succeed while others wont. At this point, all we can say is caveat emptor.

Also With This Article
Click here to view the Datalink Checklist.
Click here to view “AirCell: Finally Flying.”
Click here to view Datalink Contacts & Addresses.

-by Gary Picou

Gary Picou is Aviation Consumers avionics editor.