Weather Information & technology: Datalink helps provide the big picture

 - May 7, 2008, 9:46 AM

As the crow flies, the distance between Baltimore and Newark is only about 160 mi. But during the height of thunderstorm season, when lines of towering cumulus march eastward–often erupting into wide, impenetrable walls of rain, turbulence and lightning–the distance can easily double, while travel times can triple. No one understood this better than John Costello as he taxied an ERJ-145 from the gate at Baltimore on a summer afternoon to join the line of departures waiting for that short trip northeastward. But then Center issued a ground stop.

Costello, a captain for a national airline, pulled his trusty personal digital assistant (PDA) from his flight bag, not to make notes to dispatch about the delay, but to verify what he’d heard about the weather. Connecting to, a real-time weather information service he developed, Costello reviewed current Nexrad images, TAFs, Pireps and Metars for the route. The weather indeed looked bad, but while checking the FAA’s systems command center from his PDA, Costello also discovered that the ground stop did not apply to aircraft headed for Newark. Within 30 sec, he’d verified the state of the weather and ATC delays from the cockpit. He informed BWI ground control about the error and they quickly released his flight. Without access to weather data from the cockpit, the regional jet could well have remained a takeoff-line prisoner for much longer.

Doug Schwartz, aviation director at AT&T, uses the Airshow system installed in the company’s Falcon 2000 to pipe weather radar information up so his cockpit crews can make strategic weather decisions a thousand miles ahead of the airplane. “We need more weather information brought into the cockpit,” he noted. “In corporate flying, our product is time. To the extent that weather information delivery affects time, it interferes with delivery of our product. Anything we can use to help us sell time makes us more successful. Up-to-date weather information in the cockpit or on the ground allows us to adjust departure times and routes. We can propose many solutions when we know what we might be facing early on.”

Not so many years ago, a weather briefing meant calling Flight Service with the prospect of a long wait before speaking to a live person. If your aircraft just happened to be based at the same airport as the Flight Service Station, you could even walk right up to the briefer’s desk for a truly interactive experience–not simply listening to the forecast but actually looking at the charts and watching, first hand, as the briefer organized a plan just for you. It was all very hands on but, unfortunately, not too efficient.

Changing Times

As traffic increased and budget walls arose, the FAA found itself trying to offer more briefings with fewer personnel. In the late 1980s the FAA believed it was capable of mounting an automated briefing service to supplement its already overworked FSS staff. Very quickly it became clear that this was impossible. But the FAA at least recognized the problem and asked for bids from private contractors to provide online weather briefing services to registered pilots, which evolved into DUAT, a cornucopia of weather and flight-planning services available via computer.

Now we have lots of weather data. But it is not simply evolving technology and traffic that are driving the need for all this information. In February 1997 the Clinton Administration announced a goal of reducing fatal aviation accident rates 80 percent by 2007. Experts believe weather is a causal factor in some 30 percent of all aviation accidents, with many due to a lack of weather situational awareness in flight by cockpit crews. While preflight weather information offers pilots an opportunity to plan their flight strategically, all of that great graphical weather interpretation at the FBO is downgraded to a tactical look at the onboard weather radar. That essentially means practically flying to the face of bad weather and making a left or right turn, or a complete diversion, at the last minute.

A NASA Langley Research-sponsored team identified weather-related accident prevention as a prime goal. NASA would conduct the research to develop and evaluate prototype weather information distribution systems, while the FAA and industry were taxed with implementing the best of those technologies. The ability to display and use real-time weather information aloft was seen as a method of bringing both strategic and tactical weather information into the loop to separate aircraft from hazardous weather, much the way ATC separates aircraft from each other.

Certainly technology has taken dramatic leaps in the past 18 months toward the goal of delivering up-to-the-minute weather data to pilots, whether they’re on the ground or in the air, with even more new weather delivery systems about to be released. Web sites abound with resources, and more corporate players–both large and small–are jumping on the bandwagon, all trying to become the provider of choice.

Paul Stough, aviation weather information team leader at NASA Langley, said, “If you want to be in the weather-information delivery market, you have to get going now or you’ll be left in the dust. But the battle cry is information, not data. We operated for years somewhat data sparse. Now we must be careful not to overwhelm pilots with data they’ll never have time to read or use. We are trying to be strategic with information. But how we deliver the information is a challenge. There are different display types and interfaces to cope with. In a general aviation airplane portable laptops can work. Then there are tethered and panel-mounted displays.”

Data Transmission Methods

But the displays are only part of the pie. There is also the pipe–the conduit for the information–to consider. If it is datalink, will it arrive via a traditional ground-based broadcast station or via a satellite? There are also versions of data transmission that arrive in the cockpit via airborne cellphones.

Stough added, “It is still quite an expense to get the weather information to the cockpit. There has been slow implementation of datalink weather to airliners because of the economy, despite the technology they already have on board such as in-flight entertainment, Internet connections and tv datalinks. But on the GA side you’ve seen an explosion of datalink weather technology, because the economic downturn hasn’t affected corporate operators as much as it did the airlines. Someone who owns and operates an airplane wants this technology now because datalinked weather improves their efficiency.”

Although the weather information world is swiftly evolving, it is reminiscent of the chaos in personal computer manufacturing and sales; lots of hardware all designed to work together toward some similar end, but fraught with potential compatibility issues. Jim Falen, business manager in Honeywell’s global data center said, “You can mix and match equipment, but it can be difficult at times. We deal with compatibility issues every day with Collins and Universal boxes, for example. But we do make it all work.”

David Laubner, WSI’s director of marketing, added, “There are so many people out there now with new products and services that getting information to the customer about all their options with lots of different competing technologies can be very confusing.”

Even the term “datalink” is loosely defined. Laubner explained that like cable tv service, “WSI provides the data service and the cable modem box. The customer provides the tv, or in the aircraft version the MFD, to present the information.” File size and transmission style–almost everything is currently sent in an analog format–can also be problems. Arinc’s emerging new VHF Data Link 2 (VDL-2) is all digital.

Simply transforming any raw data into useful information is also a challenge if not done correctly. Consider how valuable Hiwas information is, yet how confusing it is to track and how often pilots avoid it thanks to Hiwas’ arcane geographic references.

For the buyer, compatibility issues would seem to point them toward a larger player such as Universal Weather, WSI, Honeywell or Rockwell Collins, unless the flight department manager has the time, resources and expertise to begin combing through all the possibilities alone. Some companies make the equipment and some provide the uplink services, while still others own the ground systems that analyze and transform the hard weather data into a product with each company’s own unique look and feel. On the ground, Internet sites available for the price of a browser are legion in number. A Google search for “aviation weather online” returned 73 pages of links, far more than most people would even care to investigate.

NASA has adopted Aviation Weather Information (AWIN), a compilation of weather products and delivery systems. Weather information is sent using either a reply-request system, a pure radio broadcast arrangement or some combination of both via a ground-based or satellite datalink and later combined with some resident data on board the aircraft to develop the full picture the pilots see. The benefit of satellite transmission is that it is available almost anywhere, on the ground or in the air, while broadcast formats have large holes in coverage areas. NASA expects to see a 50-percent penetration of the market with these technologies within the next eight to 11 years, with maximum penetration within 25 years.

Digital in Its Infancy

While ground-based preflight weather briefing infrastructure is already established, the real challenge lies in the fact that, despite Arinc’s new datalink system, digital transmission of data to an aircraft is still in its infancy. NASA believes only a digital datalink will handle the bandwidth-hungry graphic data files. But weather transmissions alone are not considered sufficient to justify their own datalink. It will be necessary to piggyback with other information sources such as ATC or in-flight entertainment systems. The benefits of digital will be vast when it comes to fruition. VDL-2 has been selected by the FAA for its controller-pilot datalink communications (CPDLC); it provides 10 times the information delivery capabilities of traditional ACARS and supports the transfer of graphical weather data.

Data-transmission speeds can appear agonizingly slow compared with those of current ground-based broadband systems, with between 2,400 and 4,800 Kbps common. The goal is to expand this to hundreds of kilobytes per second in the next few decades. NASA research with Honeywell has tested datalinks running in the 31.5-Kbps range. But even VHF digital datalinks are not expected to fill more than a relatively short-term place in transmission of weather data. Broadband, possibly through satellites, is eventually seen as the solution to this issue, but this is not expected to be available for another decade at the earliest.

Perhaps because of the wealth of weather information available in both the public and private domain, the issue of just which bits of information should be sent to an aircraft has emerged. NASA believes there is no single answer. The best opportunity to reduce accidents comes from weather information delivered via the radio, airborne weather radar, pilots looking out the window and datalinked updates. But this can be assessed only after research confirms what data is useful to a
pilot in flight, and which is superfluous.

NASA’s preliminary research does seem to identify a few keystones. For example, displaying the aircraft’s position on an MFD or any external unit is important in accurately analyzing the weather on the route ahead. Referencing the age of the data presented, rather than the time at which it was created, is also important, as is the ability to loop Nexrad images to develop a timelined display of the data.

Honeywell and Arnav partnered in late 1999 with the FAA to bring to fruition the Flight Information Services Datalink (FISDL), the Web overlay plan for data distribution. The FAA offered two VHF frequencies for free datalink testing in exchange for the two vendors’ later providing a certain amount of weather data to users at no charge. Participating aircraft will need to be equipped with certain airborne displays, airborne and ground-based servers and datalink services. Nexrad mosaics, for example, may become available at additional cost. The two companies are now beginning to offer those subscription broadcast services in roughly the same areas of coverage as flight watch–5,000 ft agl to 17,500 ft agl.

Flight Options a Firm Believer

The concept of getting data to the cockpit is beginning to take hold in a number of different organizations. Flight Options came to weather datalink services a bit differently from some others, said Jim Miller, the fractional provider’s executive vice president. “In 1998, Kenn Ricci, our CEO, recognized a problem. Our aircraft had no home base and had little room to carry lots of paper charts, a particular problem on international flights. Lack of weather information was an additional issue. It seemed to be rational to try something electronic, but you can’t use a laptop easily while you’re flying.”

All 200 of Flight Options’ aircraft are now equipped with Fujitsu handheld computers that connect via a tethered cable and gather weather data via VHF datalinks. “We probably spend $75 per month per aircraft right now on data-transmission service,” noted Miller. “But all of the weather we want is available on DUAT. We’re trying to think of a way to package that all together on our own Web site and simply worry about an Internet pipe to the aircraft. It might be easier to have a homegrown product than to purchase one. But the question is whether or not we can find software sophisticated enough, or whether this idea might just be out of our reach right now.”

DUAT is an often-overlooked weather delivery information system since it is limited to ground-based access, but it might attract more attention if Flight Options’ experiments prove successful. DUAT is at the most basic point of weather technology interaction, not because it is simplistic–hardly the case–but because it is free information provided by the FAA, which introduces an element of user skepticism.

Two DUAT players are responsible for all FAA online weather briefings–Dyncorp and GTE. Although both are government contractors performing essentially the same job,
the two remain in force to maintain competition. GTE DUAT operations manager Chris O’Donnell said, “DUAT offers the opportunity to file IFR, VFR, DVFR and ICAO flight plans thanks to our direct links with the FAA’s computers. Our graphical weather data comes directly from Harris Corp., which supplies weather to ATC centers, while the text data is sent to us from the FAA’s weather message switching center in Atlanta.”

The FAA pays GTE for each pilot-initiated briefing transaction, but does not reimburse GTE for any additional products it provides. Since more transactions mean more cash, the motivation is there for GTE to enhance its products. GTE expects to introduce animated graphics in the near future. “We also offer some of the most up-to-the-minute weather in text format,” O’Donnell added. “We don’t just pull information from the FAA’s live weather database; we’re connected directly to it. When an observer, an ASOS or an AWOS report is made to the system, we’re instantly updated.” O’Donnell reported that 200,000 pilots have registered for DUAT service since 1990, but had no current user figures. It remains the most inexpensive method of accessing weather information on the ground.

Weather Info Providers

When dialing in from a laptop, it might appear that all providers offer the same information, but as in any business model some companies focus on different aspects of the same arena. WeatherTap’s program manager, Robert Parsons, explained, “We shied away from cockpit weather delivery because we don’t think the market is that big. There are also liability concerns.” WeatherTap is available via any Web browser and a password for the subscription service.

WeatherTap offers not only weather data retrieval, but also the opportunity to overlay a variety of maps onto those images, such as interstate highways, county boundaries and airport IDs, allowing a truly personalized weather briefing map often not available to those located a distance from a weather-reporting station. WeatherTap’s Radar Lab product users can also view satellite imagery and storm tracker, as well as animate much of the other weather data available on the site. It is all organized and easy to read, but is available only on the ground.

And Parsons isn’t too hot on PDAs, either: “Weather downloads are very graphic intense. Most of those PDA screens are very small. That limits their usefulness. The biggest limiting factor, though, is the link to communications. Wireless technology is still pretty infantile for this kind of application. Technically, you’re not even supposed to use a cellphone on the ramp.”

Bryan Vester, senior director of marketing and strategic management at Rockwell Collins, addressed in-flight weather gathering: “We primarily address the flight deck through the FMS CDU and the MFD, a file server and a communications management unit, as well as the antennas for all of this. The new Cessna Citation CJ3 will offer the Rockwell onboard file server as standard equipment. The system uses Ethernet interfaces like many ground-based networks and active-matrix LCDs.” The Collins File Server Unit (FSU) supports real-time datalink weather images that Pro Line 21 operators can receive through a variety of subscription services.

Universal Weather graphics and text information will soon be uplinked to Collins-equipped business aircraft by WSI. Universal Weather offers a wide range of graphical weather information, in addition to its traditional textual weather capabilities, including Nexrad and echo/tops movement data for the continental U.S., as well as worldwide turbulence, icing and wind information. For operators who require only graphical weather data, WSI offers broadcast satellite weather reports providing one-mile resolution of Nexrad data overlaid with Metars, Sigmets and echo tops. “WSI covers pilots from preflight weather planning to touchdown,” said Laubner.

The Billerica, Mass.-based company has a wide range of experience in weather forecasting and delivery since it is owned by Landmark, which also owns the Weather Channel, and the Pilotbrief Internet service. A non-certified version of WSI’s satellite-broadcast weather products will debut this fall, with a fully certified version available early next year. There are advantages to a broadcast model of data transmission, according to Laubner. “As a broadcast model, there is no pilot interaction necessary to get the data. It gives us a chance to make a flat-rate pricing plan. Also, if we use satellite transmission, service is more reliable.”

WSI’s staff of 100 meteorologists process the data from Nexrad to develop its own unique look and feel. “Not many companies have functional products in the air,” said Laubner. “It will actually be years before we learn what pilots want and what they will accept. A few companies will set the standard. In a few years there will probably be just one or two services that pilots will depend on.” WSI, for example, is not yet available internationally due to satellite-coverage issues. The company expects rollout of global coverage by the end of next year, although Laubner said, “The need for international coverage has been mixed.”

Honeywell owns and operates the Global Data Center (GDC), familiar to many flight crews as the AFIS people, the first airborne information system for business aviation with Acars-like functionality with the ability to transmit and receive data from almost anywhere. Global’s request-respond uplink weather system will soon include Nexrad, Sigmets, winds aloft, Catmet, icing, turbulence and convective-weather forecasts. However, pilots currently can request GDC updates only every 15 min.

On the Global network, much of the required map is again stored on board the aircraft, which means that this is the only data that needs to be sent aloft, making for smaller transmitted files and faster delivery. Since the FMS knows where the aircraft is, it is also easy to superimpose aircraft symbology over the data displays. Global’s system automatically switches between VHF datalink and satellite delivery for optimum efficiency. Transmission rates at Global vary between 2,400 and 9,600 baud, although Falen said, “We still think that is pretty quick.”

Universal Data Link’s senior manager of meteorology operations, Kyle Tupin, claimed, “We’re the AOL of this airborne weather-delivery world. We supply eight different images, and nearly all provide worldwide coverage, such as IR satellite, winds and temperatures aloft, IFR/MVFR analysis, composite radar, icing and turbulence. We’re standard on Boeing’s BBJ.” Brian Allen, manager of Universal Data Link sales and marketing, explained, “Graphics have been getting lots of attention. But pilots honestly don’t ask for graphics all that often. When they need it, though, they say it pays for itself.”

Flight Options is looking at new technologies on its own to solve some of the problems inherent with weather data transmission. Some of those options are currently under evaluation on four of the fractional provider’s aircraft. “We have Air Cell on board all aircraft, but that’s a slow, analog-based system,” said Miller. “In the U.S., VHF data transmission is OK, but in South America and Canada performance can be erratic. The Iridium offers a 300-baud digital signal bounced satellite to satellite, which means it works fine on the ground in Milan. We’re moving to all Iridium telephones in our aircraft for voice and data. We are slowly rolling out the weather graphics in the cockpit.”

George Vaeth, chief pilot at Hunt Oil, operates a Challenger 601-3A with Honeywell CDU-820 and NZ-6.0 software for the company’s airborne weather collection. “We’re able to get better information now. We use all the weather maps the aircraft can download to see the weather 3,000 miles away and plan our detour early on.

“The only thing I wish is that the radar picture we download had more definition. I know they didn’t want to let the file sizes get too big, but it seems to paint weather worse than it really is. A front might only have scattered cells, but it can look much worse [on the image]. But then this is strategic information. You certainly can’t use it to pick your way through weather anyway.”

Allen added, “The cost to get into this new weather information distribution market is very high. It is moving forward, but not as quickly as people expect, despite the fact that GA doesn’t often have the financial restrictions the airlines do. The main thing people are forgetting, however, is that many of these services are available only in the U.S. But GA is not only a U.S. market.”

Flight Options’ Miller may have organized his thoughts best in what is a confusing technological challenge: “We need to see a wideband pipe for airborne data to really evolve. But getting truly high-speed data to an airplane requires a point beam off a satellite, which means using a parabolic antenna. That could cause dropouts. For now, we are evaluating Honeywell and WSI, among others. We’re going to just sit back and see who wins.”