The Scan Before the Storm

The latest weather radar offers new benefits to passengers as well as pilots.

Knowing with confidence and precision where bad weather is makes for more than just safer flying. Flight planners and pilots can save a lot of time and fuel that would otherwise have been spent avoiding possible hazards. They can also smooth out your ride.

Radar has been around since the late 19th century, when scientists discovered that low-frequency radio transmissions were disrupted when they bounced off metal objects such as ships, and later, airplanes. During the run-up to World War II, scientists on both sides of the conflict realized that the “interfering” hunks of metal could be not only located, but also tracked on a crude video screen—just in time for radar to play a pivotal role for the Royal Air Force in the 1940 Battle of Britain. In fact, that’s the year when the word radar—a U.S. Navy term, somehow shorthand for “radio detection and ranging”—was born.

The first experiments in weather radar centered on lightning detection. But early military radar operators were frustrated to find that the heavy rain inside thunderstorms caused their systems’ transmissions to bounce back. Soon, purpose-built radar systems were installed in aircraft to detect towering, dangerous storms that would otherwise have been hidden by thick clouds or dark of night. But these systems were imperfect and required a lot of cockpit time and skill for pilots to operate.

Recent developments in weather radar have significantly improved the science. The result is not only greater safety, but also improved efficiency in flight planning and much better capability in predicting and avoiding turbulence. Mostly, that is accomplished by defining more precisely where the weather is (and isn’t), but also by comparing the atmospheric conditions with historic data.

The direction and coverage of a radar system’s outgoing transmission is where new technology has advanced the science. Legacy systems’ antennas pan across the sky, sweeping a 60-degree arc in front of the airplane. Each back-and-forth scan takes several seconds. The transmission arc is also limited in its vertical coverage, and scans the sky in swaths of only about 1,000 feet from top to bottom at the range out to about 60 miles. If the radar operator wanted to know what was happening in the sky above or below the standard area of coverage, he could “tilt” the radar to scan higher or lower. Skilled operators developed strategies for tilting and interpreting their scans, but even for an expert, it took a lot of time and attention that could otherwise have been devoted to other cockpit duties.

IntuVue weather radar as a “3-D” system, as distinguished from what it terms legacy “point and shoot” radar. (Rockwell Collins offers a comparable system called MultiScan.) The IntuVue software, rather than an operator, directs the scanning process. Each scan takes less than 30 seconds—much less time than earlier radar required—and it covers a wider swath of sky: 180 degrees in front of the airplane out to 320 nautical miles and from the ground up to 62,000 feet. The analytical software reads what the radar sees and delivers a detailed diagnosis, not only of damaging storms, but also of weather that is likely to produce lightning, hail and turbulence based on comparing specific weather conditions with historic data. It’s as if the radar were performing a continuous CAT scan of the sky ahead.

IntuVue’s technology also increases the strength of the radar’s transmission, giving it greater range. Plus, the radar “box” inside the airplane is much smaller and lighter and uses far less electricity than legacy weather radar systems. Just like a high-definition television, moreover, higher-resolution displays in the cockpit allow designers to provide more detail for pilots. And for the future, Honeywell is exploring datalinking radar analyses, so every radar-equipped aircraft can become part of the worldwide weather data-collection process.

The more we know, the more we can can do. The latest weather radar can help.

Mark Phelps is a managing editor at BJT sister publication Aviation International News.