Enhancing Avionics

New devices improve safety and situational awareness


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.

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