Enhancing Avionics

In the world of commercial marketing and advertising one of the most used catch words is “Enhanced.” The intended meaning is to elevate to a higher degree; intensify; magnify which in turn translates into raising the value and subsequently justifying an increase in profit for the marketers.

Rapid technological advancements have provided avionics manufacturers the ways and means to improve value in their products by enhancing reliability and capability.

Commercial aviation as we know it has for years depended on something referred to as “Basic T” to provide information to flight crews. This concept originated from the layout of the flight critical displays housed in the instrument panel and includes: airspeed, attitude, altimeter, and direction. Is this basic criteria still needed for flight in this day and age?

Without a doubt it is! By employing digital technology and sophisticated processors it now becomes viable to enhance the basics by super imposing supplemental information on the age-old display. Within the last 30 years we have witnessed a true renaissance in flightdeck instrumentation. Prior to the 1980s any addition to cockpit instrumentation involved locating an available space and then cutting a hole in the instrument panel, installing a gauge, running additional wires and switches, and reworking the weight and balance.

Retrofits available
The good news is that the enhancements are now available throughout the aviation industry. In many cases retrofitting older aircraft with current generation equipment often provides operational enhancements including wide area augmentation system (WAAS) and automatic dependent surveillance broadcast (ADSB). These changes can benefit the operator in removing aging equipment and installing devices that are often smaller, lighter, and frequently require less maintenance.

The attitude and heading reference system (AHRS) unit provides aircraft attitude and heading information to both the primary flight display (PFD) and the multiple function display (MFD), and the air data computer. Some aircraft utilize attitude heading reference systems (AHRS) units containing advanced sensors (including accelerometers and rate gyros) which enable pitch, roll, and yaw data to be displayed to the flight crew and interfaces with the magnetometer or flux detector to obtain the earth’s magnetic field reference, draws on the air data computer to obtain pitot and static numbers, and also to obtain satellite navigation information.

The air data computer processes data from the pitot-static system and outside air temperature (OAT) sensor(s) and in some cases an angle of attack (AOA) probe. This unit provides pressure altitude, airspeed, mach number, vertical speed, OAT, stall, and over speed information to the integrated avionics system, and communicates with the PFD and AHRS units. The air data computer may also be connected to an automatic flight control system (AFCS).

Synthetic vision
Controlled flight into terrain (CFIT) continues to be the No. 1 cause of accidents in general aviation. Pilots cannot see obstructions or they lose the horizon, and fatal accidents occur.

Synthetic vision systems (SVS), a new aircraft system technology that could nearly eliminate those accidents, has been the subject of intensive ongoing research and development and now synthetic vision technologies are moving off the drawing board into the cockpit.

Synthetic vision combines a high-resolution display, databases of terrain, and global positioning system (GPS) technology to show pilots exactly where they are and how the aircraft is oriented. The system also has an integrity-monitoring system that ensures the information synthetic vision is displaying corresponds to where the aircraft actually is.
As PC gamers know, computers can generate scenery that is real enough to draw you into the action. Aircraft software also can create “synthetic” terrain by rendering stored data into a 3-D picture. Aided by sensors, synthetic vision can improve safety and situational awareness, not just in high-level cruise, but also in high-speed, low-level maneuvers. It can improve the effectiveness of unmanned air vehicle (UAV) operations, as well. The synthetic view remains clearly visible at all times.

The idea for synthetic vision has been around since the 1950s, but until recently, implementing it had not been technologically possible until recent new developments in displays, processors, and graphics. Synthetic vision details the terrain, obstacles, the approach path, and runways in a reality-oriented display that looks something like a video game.
Synthetic vision’s promise lies in its ability to fuse 3-D data into intuitive displays that can provide life-saving awareness to flight crews. Synthetic vision’s database-driven symbols have the potential to greatly improve flight safety and mission effectiveness. The U.S. Air Force is applying synthetic vision concepts to unmanned vehicle control stations; in the civil sector, the concept has expanded to general aviation as certification issues are being resolved.

EVS stands for enhanced vision system, a forward-seeing imaging system that consists of an exterior-mounted forward-facing infrared (IR) sensor; signal processor; and a means of producing a cockpit display. During poor visibility conditions, such as fog, haze, smoke, precipitation, and darkness, EVS provides the pilot with actual monochrome pictorial images of terrain, runways, taxiways, aircraft, and other potential obstacles including animals. This is accomplished by observing temperature differentials.

For years, military aircraft have used infrared sensors for nighttime missions. Recent advances in technology and miniaturization have finally made EVS feasible for general aviation applications.

As airports and airways become more congested and as more flights venture into less sophisticated airports of the world, aviation is demanding what EVS promises — improved flight crew situational awareness to reduce runway incursions during take-off and landing, controlled flight into terrain (CFIT), approach and landing accidents along with unwanted encounters with wildlife.

Weather data
Employing a unique space-based platform of geostationary satellites positioned to provide continuous data link coverage across the continental United States (and parts of Canada), XM WX Satellite Weather is a recent addition with the ability to heighten in-flight safety and pilot situational awareness. In any aircraft, at any altitude, XM WX provides the weather data pilots need for better flight planning and in-flight decision-making.

Viewable on a wide variety of portable and panel-mount cockpit displays, satellite weather provides aviators an accurate and real-time view of the meteorological conditions ahead.

XM weather data flight deck display is enabled by WxWorx, (a leading provider of weather analysis for the broadcast television industry). More than 20 different types of graphical aviation weather data including detailed NEXRAD and METARs data, as well as current reports on precipitation, lightning, winds aloft, echo tops, freezing levels, turbulence, TFRs, and more can be overlaid onto a flight deck display such as MFD or even an electronic flight bag (EFB). The reliability and popularity of the XM WX data link solution is evidenced by the fact that many of today’s airframe manufacturers have adopted this technology as an available feature on their aircraft.

The same XM Satellite technology that delivers weather data to the cockpit can also be used to provide the ultimate in digital audio entertainment. One XM antenna can support both XM weather and XM radio data links. So, with an additional XM subscription and a sound-enabled receiver, passengers can relax and enjoy more than 170 channels of continuous music, news, talk and sports programming while flying anywhere in the continental United States.

The enhancements of today will soon become the standards of tomorrow and although newer digital technology might claim to provide improved reliability it does become the responsibility of technicians to learn the principles and concepts as a whole new set of challenges will be ours to overcome.

Jim Sparks has been in aviation for 30 years and is a licensed A&P. His career began in general aviation as a mechanic, electrician, and avionics technician. In addition to extensive hands on, Jim created and delivered educational programs for several training organizations and served as a technical representative for a manufacturer of business jets. Currently when not writing for AMT, he is the manager of aviation maintenance for a private company with a fleet including light single engine aircraft, helicopters, and several types of business jets.