WAAS Up?

Originally Posted October 9, 2008

The flight school where I work part time as Assistant Chief Flight Instructor added a new Cessna 172 to its training fleet recently. Like two others we operate, it is equipped with the Garmin G1000 integrated cockpit system. Unlike the others, this airplane is also WAAS equipped. WAAS (Wide Area Augmentation System) adds to the precision of the GPS navigation system by adding a signal broadcast from the ground.

In many ways, the addition of WAAS is a subtle change. There is no WAAS switch and no WAAS light to tell you it is working. It does, however, add some very useful capabilities. Among these are the ability to navigate vertically as well as horizontally. The system will provide guidance during descents in cruise and on instrument approaches. The glide path it displays looks and works very much like the glide slope for an ILS approach. There is also a general upgrade in the accuracy of lateral guidance over GPS-only equipment.

The primary benefit of WAAS lies in its ability to provide accurate vertical guidance. So many accidents result from the pilots’ lack of awareness of where the airplane is relative to a safe descent path. The WAAS system, properly used, can help to fill that gap.

WAAS capability comes with a price, however, and that is additional complexity. To fully take advantage of its capabilities requires additional programming and an enhanced knowledge of the modes of operation and displays. Autopilots designed to take advantage of WASS also have more features, and therefore a steeper learning curve.

Like so many technological innovations over the past several years, WAAS requires a bit of training before the pilot can really take advantage of it. This is yet another reason to be sure you spend some quality time with your instructor to receive personalized training on the equipment you use.

Fly Safe!
Neil