Every pilot who stays reasonably up to date with the march of aviation technology knows that today even pilots of piston singles and light twins can get aviation weather in the cockpit. For those pilots who fly their airplanes for transportation, this is nothing short of a safety revolution. Instead of guessing and hoping and sweating, we can now fly with a high degree of confidence that we'll be able to avoid severe weather. This information also allows us to make better strategic in-flight decisions, including modifying routing, altitudes and diversions. Say you're 250 miles out. How's the weather at the destination? Instead of waiting until you're almost in the pattern, check out the conditions at the destination, and if it's too low, make a new plan before you find yourself in the middle of some crud you'd wish you'd never gotten close to.
Getting weather information is huge, but datalink can also give pilots updates on airspace changes, most notably areas of temporary flight restrictions (TFRs). This is a big deal, especially for VFR pilots who, even if they're getting flight following, have no guarantee of staying clear of restricted airspace. If a TFR pops up suddenly, or if its limits grow, say when the President stops by his ranch in Crawford or Camp David, as soon as the receiver gets the updated data, the TFR will show up on the map. It's great peace of mind.
Not Whether to Buy, But What to Buy
While everybody is ecstatic that high-quality weather information is available, the proliferation of these products has made for a confusing marketplace for pilots looking to get into the game. The big questions for would-be adopters: What weather is available, what can you play it on, and how much does it cost?
Pick a Package
Standardization isn't unknown in aviation electronics, but when it comes to newer technology, it is definitely the exception. So unlike, let's say, a satellite television receiver, which you can plug in to just about any kind of TV, aviation weather receivers play on a limited number of displays. Often, that limited number is one. Consequently, when you go to pick out a weather service provider, you're usually choosing a display and an avionics manufacturer as well. So the easiest way to approach a purchase is to pick a package and go for it. But which one? Ground-up or Sky-down? Broadcast or Two-Way?
There are essentially two kinds of weather pipelines available, those that make use of some kind of satellite network and those that are built around VHF ground transmitters. Unlike satellite systems, ground-based systems are limited by terrain and the airplane's proximity to the station. But VHF is still widely and effectively used by the airlines with ACARS datalink for exchanging a variety of data-weather, clearances, and text messages-over the airwaves. General aviation has a VHF system, Bendix/King's broadcast-only Flight Information Services program, developed as part of an FAA program to promote datalink weather for the cockpit. For pilots who primarily fly in the most populous parts of the country, Bendix/King's FIS datalink offers a powerful suite of weather products, including Nexrad and graphical metars. As part of the company's contract with the FAA, you can even get free textual weather in a properly equipped airplane.
Because it was prohibitively expensive and required large, hi-gain antennas that don't fit on every airplane, satellite weather was once the exclusive domain of the biggest bizjets. But since the launch of several lower cost satellite weather options, including Echo Flite, WSI and XM aviation weather, satellite-based weather is a powerful and affordable option. The biggest benefit is that the signal comes from above, so unless you're flying under bridges or through tunnels, reception is pretty much a given (though some early adopters found that updates from some sat systems were slow to come by). And because satellites each cover a large geographical area, coverage is widespread, though pilots of these lower-cost systems are generally limited to coverage in the lower 48 United States.
There is one other factor, broadcast versus two-way communications. Orbcomm, Iridium and Inmarsat offer two-way communications capabilities, though most of the products designed to make use of those systems are intended for business aircraft. The exception is Avidyne's Multi-Link product, which uses both XM and Avidyne's own Orbcomm two-way link to provide high-quality broadcast weather through XM and two-way communications, including text messaging and aircraft tracking services, through the Orbcomm datalink.