Aviation Weather: The true story:

Two pilots who had been friends since childhood and shared a passion for aviation met a few months ago in an on-field restaurant, as much to renew old acquaintances as to compare notes on their lives and their flying. One had pursued aviation since his early twenties and progressed from renting available workhorses at local airports to owning his own Cessna 172. Over the years he earned a few ratings: he had his instrument ticket, a multi-engine rating and a commercial license. After the Skyhawk’s second major overhaul, he sold it and bought the shiny new Skylane parked that morning on the flight line. His friend had drifted away from flying after the first few years and didn’t return until he was nearly 50. He blamed business and personal demands on his time but they both knew better. If it took a mid-life crisis to awaken those dreams, so be it. Sky conditions were CAVU so they decided to burn some avgas. They finished their coffee and walked out to the parking area.

The Skylane was cleared; they took off and headed up the South Florida shoreline squawking VFR, the pilot proudly pointing out the glowing red lines on his KLN-89b and talking about how easy navigation had become with GPS. They continued north towards Lantana, a small airport residing in a notch cut into PBI’s C-airspace, about 35 miles distant. As they glanced out at the horizon, they both seemed to recognize the approaching squall line at the same time, a broad expanse of what looked like a thick dirty brown carpet obscuring the horizon. The friend flying called Flight Service for an update. It was about 50 miles north of them and heading southeast at 45 knots. He wasted no time, turned 180 degrees and headed back to their departure airport.

With 4,000+ hours between them, shouldn’t these pilots, particularly the one with the ratings, have expected the unexpected and at least looked at a radar display before getting in the airplane? Particularly in a sub-tropical region where weather can and does change quickly… Well, it was a short hop, the sky was blue and they didn’t bother. There was a working Stormscope in the panel but without lightning, it offered no warning about the approaching storm. They did do the right thing once they recognized the danger and only lost a couple of hours as the squall line passed by. But the what-ifs piled up quickly—what if this had been a night flight and visual recognition wasn’t possible? What if this fast-moving squall had been 20 miles out instead of 50? What if Flight Service had been down? What if?

Let’s just say that the incident prompted an intense discussion in the pilot’s lounge over the relative merits of portable weather, the systems collectively referred to as datalink. A King Air pilot said he wouldn’t take off without checking his radar scope and then launched into a tale about wind-shear. A local instructor stranded with his student reminded everyone that a weather briefing would have stilled this debate before it began. And there on the weather terminal was the smoking gun itself, a Chinese wall of intense convection and precipitation with little red blotches in its wake—a good place to not be flying. What everyone seemed to agree on was that the new datalink weather systems showed promise. But no one seemed to know who the players were without a scorecard.

In the door walked a recently landed pilot, dripping wet despite the best efforts of the umbrella-wielding line crew. After helping himself to hot coffee, he sat down at the terminal and reached into his pocket, withdrawing his Anywhere Wx iPAQ. “I saw that thing coming,” he said. “It was closer than Flight Service reported.” All the pilots crowded around the new arrival marveling at the resemblance between his hand-held computer and the desktop weather terminal.

As active pilots, there are a couple of things we try to practice. We don’t get into an airplane without first checking the weather to our destination and an alternate. And we say we don’t fly without a flight plan although many of us do. At $70 an hour for fuel alone, we don’t say “Let’s just check out the weather when we get up there.” Finding yourself in a storm with 45 minutes of fuel remaining is no way to wash an airplane and it can really spoil a vacation or business trip. Another thing we all do is read the accident reports, religiously.

Flight safety
The Nall Report* describes aircraft accident statistics in excruciating detail so we’ll extrapolate a few salient statistics and leave it to you to draw conclusions.

“Weather-related accidents equal high fatality rate. Weather-related accidents continue to have the highest probability of fatalities. In single-engine fixed-gear airplanes, 56.5% of weather-related accidents were fatal. In single-engine [retractables], 89.5% were fatal, and 100% in multiengine airplanes resulted in fatal injuries.”

Personal Flying comprises 45% of all GA flights yet accounts for 70% of fatal accidents. Personal Flying is easier to define by contrast. It does not include Instruction, aerial application, business, ferry, aerial observation, executive/corporate… Of the various operations involved including take-off, fuel management, descent/approach, go-around, landing, and maneuvering, Weather is the most prominent factor (82%), of which 87% involve fatalities.

“Attempted VFR flight into IMC continues to be the most deadly weather-related accident cause. 84% of those were fatal.”

We are not suggesting you turn in your normal pilot vigilance, leave off weather briefings and quit calling for PIREPs and not keep up your Instrument currency. We are not saying that the Anywhere Map system of GPS navigation, terrain/obstacle avoidance, weather, and instrument approach procedures is all you need to go forth and conquer the skies. We are simply saying that with this system you can far better manage the prominent factors of today’s flying—navigation, weather and terrain, and that helping yourself to these preventive measures won’t cost you an arm and a leg, literally or figuratively.

Robert Heinlein said “Seasons are what we expect; weather is what we get.” The point is the traditional risks associated with instrument flying that vary from day to day don’t have to be a game of chance or an extended labor of information mining. If you think of weather as “atmospheric terrain,” you wouldn’t fly without a surface chart, so why fly without a weather map? Why should you wait until you can make a visual on that gust front before you turn away? (Assuming it’s daytime and you can see.) Until recently, your options [regarding weather] included onboard radar, getting advisories before flight, and checking in with Flight Service or Flight Watch enroute. It also helped to have an extra set of sharp eyes.

With or without an instrument rating, you know that the best way to deal with severe weather is to stay clear of it whenever possible. But how do you avoid what you can’t see?

What’s wrong with aircraft radar?
Radar has merit if you can get past the price, around $45,000 for a single-engine aircraft, the limits to its performance and the fact that it’s a permanent and bulky addition to one aircraft,. The radar systems built into GA aircraft are short-range devices primarily intended to help you into and out of terminal areas. Radar’s range of visibility is a fuzzy cone emanating from the nose of the aircraft about 30 degrees wide, 70-100 miles long and attenuating quickly, so radar will report on what it sees enroute, so long as it and you are looking straight ahead. But as every pilot who has flown with radar knows, getting a grasp on the true extent of a storm or its convective surroundings is like checking the baby’s complexion with a sonogram. Aircraft radar cannot “see” beyond the first convective mass of any significance, so nested thunderstorms remain concealed. Considering the price and the 70s technology, built-in radar systems don’t deliver much bang for the buck compared with datalink.

But I have a Stormscope…
Lightning is characteristic of the core cels of thunderstorms, but it is not a prerequisite for heavy convective activity, and while its presence is truly indicative of thunderstorms, its presence or absence is no absolute marker for precipitation, ice, winds or even hail, although the likelihood does increase as these symptoms converge. A Stormscope (or Strikefinder) is a sensor responsive to lightning’s electromagnetic spectrum. It sees lightning bolts, not the electrical potential preceding a strike, and NONE of the surrounding storm or convective conditions. It is more like a stop sign at end of a road going over a cliff than any kind of convective advisory. Yet pilots continue to trust these expensive and only semi-accurate sensors because when they were introduced almost 30 years ago, they were a country mile ahead of visual interpretation. So just what do they help you avoid? Only the electrically active core of a thunderstorm, certainly not the much larger convective region surrounding it. And if you respect sage advice, avoiding a storm altogether is far wiser than fighting your way through its electrical bear traps. The Stormscope paints only the very core of electrically active storms. This is 2005 and that’s just not good enough.

Everyone loves NEXRAD…
NEXRAD starts as ground-based radar; the big domes you see at larger airports with Doppler ranging and azimuth layering. They’re extremely accurate, and with 150 or more of these networked together into an overlapping national mosaic, the result is a God’s eye view of convective weather just as you’d see on the Weather Channel. So we must ask why, if you could fly with this information, wouldn’t you want to? It’s not expensive. Taxpayer’s money built NEXRAD and you are a taxpayer. The avionics industry is building the datalink portion that pipes it into your aircraft. There are several flavors of this but the one that is becoming the de facto standard is XM Radio. A pair of orbiting satellites shower North America with integrated weather data starting with NEXRAD and including METARs, TAFs, cloud echo tops, and lightning strikes.

Like everything else of value, NEXRAD comes at a price -- time. It takes five minutes to collect and format the national radar images, get them up to the satellites and broadcast them down to your aircraft. The 45-knot squall line reported has traveled almost 4 miles during this interval. I’d call that an entirely acceptable margin of error.

Putting it all together
Datalink weather displayed on Anywhere Map has been described as an “atmospheric terrain map.” What if you could display convective activity, precipitation, cloud tops and lightning on a moving map along with your flight plan, navaids, up-to-date airspace and terrain? Weather would now be an integral part of your map, making it as easy to recognize and avoid storms as picking out the best terrain to fly. We think that Anywhere Map combined with XM Satellite weather is one the most important set of changes to avionics in 50 years.

Decision, decisions…
The decisions a pilot has to make revolve around a well-known dilemma, the FAA’s glacial rule-making when it comes to approving even the most obviously beneficial devices. So you have to weigh Datalink’s direct benefits to your personal safety and that of your passengers against the fact that it is not an entirely sanctioned device. If you buy a new Skylane with a G1000 and a GDL69 (Datalink weather), you are flying approved equipment, but if you display precisely the same nav and weather data with an Anywhere Map with XM WX system, you cannot consider this a primary instrument. It’s only money, they say, but $312,000 even for a Skylane is a lot of money. Just remember, you are charged with using any and all resources at your disposal in the safe and expeditious execution of your flight. What’s a pilot with any integrity to do?

The numbers
The Anywhere Wx portable datalink system costs $2495, ready to go. This includes a Pocket PC display and yoke mount, a GPS receiver, Anywhere Map, an XM Radio receiver, power supply and a pair of tiny antenna pods. In functional terms, the only comparable systems are the Garmin G1000 and the Avidyne. Neither of which is portable, neither of which can be retrofitted into older aircraft, and neither of which costs $2500. Should that stop you from enjoying the safety of datalink weather or a glass cockpit?