Waypoints

Editor in Chief Thomas B. Haines learned to fly when VORs ruled navigation.

Several times in the mid- to late 1990s I lamented on these pages the lack of information available to the pilot while ensconced in the typical general aviation cockpit. Three key pieces of information for safe flight were missing: traffic, weather, and terrain. Finally, in the late 1990s, manufacturers began introducing multifunction displays (MFDs) that easily interfaced with Goodrich Stormscope systems for displaying lightning data.

Over the past four years, MFDs and moving maps have become standard on every new four-place and larger airplane. Even some two-place airplanes offer such standard equipment. Systems from Garmin and UPS Aviation Technologies in particular have found their way into the cockpits of older airplanes as well. These displays form the backbone of the next steps necessary to improve GA safety: datalink near-real-time weather to the cockpit, and traffic and terrain information. You need a place to display that information and the MFD becomes the platform.

Paul Ryan, who developed the Stormscope technology, introduced the first low-cost traffic advisory system for GA. That basic and marginally performing product has grown into a line of sophisticated collision avoidance systems from Ryan International. Goodrich followed suit with the Skywatch system.While highly effective, such systems cost a minimum of about $20,000 plus the cost of the display, putting them out of reach of most pilots owning light GA airplanes.

The latest traffic system entrants from Garmin and Honeywell Bendix/King cost a fraction of that, but come with their own limitations. Called TIS for traffic information service, the systems require a Mode S transponder that receives via the Mode S datalink traffic information from air traffic control's approach radars. Assuming you have a Garmin 500- or 400-series navigator or a Bendix/King MFD, you can have a traffic alert system for about $5,000, which includes a new solid-state transponder.

However, compromises come with the low cost. You only receive the traffic datalink when within 55 miles of an approach radar site; that distance may be increased to 100 miles soon. When flying in areas only covered by en route radar systems, there is no traffic information available. Likewise, when traffic drops below altitudes covered by approach radars, it disappears from your display. But if you usually fly in areas with robust approach control radar down to pattern altitude or lower, TIS offers a good value for collision avoidance.

ADS-B — automatic dependent surveillance-broadcast — is another emerging option for low-cost collision avoidance. It uses a series of ground stations to transmit traffic information from the ATC system to participating aircraft. The aircraft receives the data via a low-cost transceiver rather than a Mode S transponder. When ADS-B is fully implemented it is expected to provide greater traffic coverage than TIS. In addition, the ADS-B datalink can also provide weather information to the cockpit.

Garmin and Honeywell have decided to grab the here-and-now TIS signal and use it to create a new product line and to improve safety. ADS-B is an FAA-developed system with promise but one that progresses at the government's usual glacial pace. AOPA has two test airplanes equipped with ADS-B and has found it to be a useful system, but it will take some time for the government to build the ground stations necessary to provide a useful amount of coverage.

As with ADS-B, Honeywell uses a series of ground stations to provide near-real-time weather to the cockpits of its customers. The information is displayed on one of several models of Bendix/King multifunction displays either already on the market, such as the KMD 550 or 850, or the KMD 250, a smaller, lower-cost display due out this summer. We've been flying behind a KMD 850 with the flight information system (FIS) for more than a year and found it to be an aid in avoiding severe weather. The pilot interface is well conceived and easy to use. Coverage above 10,000 feet msl is good. Most of the country is blanketed with the signal above 5,000 feet. A few lightly trafficked areas of the country do not have coverage at 5,000 feet or below.

Several other companies have decided that satellite delivery of weather information is a better way to go. Satellite coverage areas tend to be greater if not universal. In addition, satellite coverage is usually available on the ground, allowing a pilot to get a good look at the weather before takeoff. FIS signals are not usually available on the ground unless there's a tower nearby.

Garmin, partnered with EchoFlight, receives weather information from the Orbcomm constellation of low-Earth-orbit satellites. The Nexrad and other weather information is captured by a Garmin GDL-49 receiver/processor and displayed on a Garmin MFD. During our evaluation flights, the system performed mostly as advertised, but occasionally it has difficulty maintaining a satellite lock long enough to quickly deliver the weather information. Sometimes it can be several minutes before a request for information is fulfilled. Software and receiver improvements in the works may enhance the performance.

EchoFlight itself and Control Vision also offer portable moving maps that can be equipped to receive weather data, offering those with space-challenged panels an alternative to installed systems. (See " Portable Weather: Control Vision's AnywhereWx," April Pilot.)

Avidyne also utilizes the Orbcomm satellites for its weather datalink — a standard feature in Avidyne's FlightMax EX500 and EX5000 MFDs. Avidyne uses a "narrowcasting" concept to automatically send weather products and airspace updates — including temporary flight restrictions — to the cockpit based on the flight-planned route stored in the aircraft's GPS, although the pilot is able to request weather products outside of the flight-plan area.

While those using the Orbcomm satellites employ some sort of request/reply system for weather information, WSI uses a satellite continuous broadcast method to deliver weather content to the cockpit. WSI is developing an interface for the UPS Aviation MX20 MFD and other panel-mount displays. It also interfaces with various portable displays, such as the tablet-style computers becoming popular as part of electronic flight bags.

The third part of the GA information trifecta is terrain. Displaying the information on its MX20, UPS Aviation was the first to combine a basic terrain database with GPS position to give the pilot an awareness of nearby terrain at a low cost. Garmin recently announced that it would also be introducing a similar system late this year as a software upgrade to its 400- and 500-series customers. In addition, Garmin plans to introduce a Class B terrain awareness and warning system (TAWS). While the basic system uses color shading on the displays to alert the pilot to nearby terrain, TAWS is more sophisticated, providing visual and aural alerts and also taking into account aircraft configuration — such as landing gear and flaps down — before it issues an alert (see " X-ray Vision: Sandel ST3400 TAWS/RMI," page 129). Even more sophisticated — and expensive — systems, such as Honeywell's enhanced ground proximity warning system (EGPWS), provide an even greater level of detail and alerting.

Honeywell in late April announced a new enhancement to its EGPWS that takes advantage of the system's detailed airport database to issue alerts when the airplane is on or approaching a runway. With the Runway Awareness and Advisory System (RAAS), the pilot hears a voice annunciation as he approaches a runway while taxiing or from the air. Once taxiing onto the runway, the message changes to inform him that he is on a runway.

With traffic, terrain, and weather information becoming available in flight, the next step is to combine them with other systems into more user-friendly displays. For that, Chelton, Meggitt, and Avidyne already offer primary flight displays with solid-state gyro systems. Garmin and Bendix/King will offer their own solutions in the near future.

Next up? MEMS — micro electro mechanical systems — tiny sensors and machines that can be employed to do all sorts of work in airplanes — from sensors to valves. Crossbow Technologies already employs MEMS gyros in the Chelton PFDs. Honeywell is a leader in this emerging field and will be deploying such technology into future navigation, attitude sensing, and pressure sensing systems.

Following the traditional technology trend, these devices will become less expensive, smaller, and lighter as time goes on, soon finding a home in a cockpit near you.

E-mail the author at [email protected].