“That is weapons-grade accuracy and reliability,” the former Top Gun instructor tells me over the headset.
We are hugging the right side of a canyon, a position reflected on-screen by a twin-engine icon on the right side of a narrow band of green, sandwiched by bands of fire red. “You don’t want to fly down the middle,” Nelson says. “If you run into trouble, you want to be able to turn around.”
As if by tradition, Alaska is again the proving ground for a new kind of ADS-B. ALAS has followed our trip up through the Kenai Mountains, over the glassy heights of the Skilak Glacier, and across the Harding Ice Pack. Throughout, we have been in a “terrain shadow,” where neither radar nor terrestrial ADS-B could see us. The Navajo continued in this shadow, flying down the Ailik Glacier, with its eerie blue crevasses, then over the Kenai Fjords and Resurrection Bay, past Seward, and back to Anchorage, each step plotted on the ADS-B displays on the airplane’s instrument panel.
ALAS provided the data link that ground stations alone could not, but the information was the same as that from a standard ADS-B system: pinpoint location of the airplane, its altitude and heading, the 3D moving terrain, the texting, and weather maps. Before Capstone, none of that was available.
In 2007, the National Aeronautic Association presented the developers of ADS-B, Nelson included, with the Collier Trophy. Displayed in the National Air and Space Museum, the trophy is awarded each year for “the greatest achievement in aeronautics or astronautics in America, with respect to improving the performance, efficiency, and safety of air or space vehicles.” Nelson and I are now completing the test of an even better version of ADS-B.
As we near Merrill Field, the mountains recede, as does the bright red on the Chieftain’s 3D terrain map. We bank toward the airport, and through the windscreen, we see Runway 25. A few miles farther are downtown Anchorage and the FAA regional office, where the modern age of navigation began. Behind me, its lights blinking green, is one possible future.
Frequent contributor Greg Freiherr last wrote “Orbiter Autopsies” (Apr./May 2012), which reported on NASA’s examination of the shuttle fleet.