Electronic Flight Information System.

Well this need not be such a dream. The DYNON AVIONICS EFIS (Electronic Flight Information System) EFIS-D10A provides a solution to just about all these problems. It is inexpensive and affordable, whilst also being technically very competent and of an ergonomically compact design that has an easy to read display system!

The instrument in its basic form is totally self contained with most of its necessary sensors and will fit into a standard 3 and 1/8 inch instrument panel hole. With an overall behind the panel depth of less than seven inches (180 mm) it is also comparable in size with many mechanical Artificial Horizons. Yet it combines the full functionality of 10 instruments vital to the small aircraft pilot. The only external inputs required are the aircraft power supply, and pitot & static pressure lines.

The display screen is also similar in size although generally slightly larger than your present Artificial Horizon. It comprises a LCD (Liquid Crystal Display) that (at 450-nit) is readable in bright sunlight. This is much brighter than your laptop or tablet PC (Personal Computer)

Using modern solid state electronic components throughout the problems associated with wearing out and sticking of mechanical devices have been eliminated. Included are state of the art qyrometers, magnetometers, accelerometers, pressure transducers, and temperature sensors as necessary for sensing all aspects of the aircraft’s movement. These devices are combined with the power of four microprocessors which correlate all the sensory inputs and provide an accurate, fault tolerant and easy to understand multifunction display.

Figure 1

Aircraft attitude in pitch and role is presented and works in the traditional way with blue sky and brown ground segments defining the artificial horizon. The bank and pitch angles are also represented as usual with lines and tics’.

Magnetic heading is shown by means of tape readout at the top of the screen with normal compass numerals shown at 10 degree intervals. A fixed triangular pointer positioned centrally on the tape is used to alert you to your current heading. In use it functions much like a standard cockpit magnetic compass except that your turn decision onto the desired heading is made more naturally left to left and right to right. The aberration of a standard magnetic compass when turning onto the major ordinates is of course not present in this display since it has the stability of a gyroscopic instrument.

Airspeed is presented in two forms and both are positioned on the left-hand side of the screen. Firstly there is a vertical moving tape giving the standard coloured white/green/yellow/red graphical indications of stall, flap limit, normal, caution and maximum flight ranges together with airspeed numeration at 10 knot intervals, all increasing naturally in ascending the column. A triangular fixed pointer shows your current airspeed. Each of the coloured ranges and the airspeed scale can be adjusted and set to match the parameters of your particular aircraft. This is achieved by means of a PC support program and connector that may be used either at home or by the instrument supplier. The second presentation can be seen in the upper left region of the display and is a digital readout of your actual airspeed.

Centred just below the heading tape is a rate of turn indicator. This is depicted by a yellow bar that grows horizontally from a black vertical anchor line in the direction of aircraft yaw. Small triangular arrows on each side of the anchor line indicate the position to which the yellow bar must extend when performing a standard rate one turn. At the bottom centre of the screen there is a black ball slip indicator. To maintain balanced flight the ball needs to be constrained horizontally, as is normal for a turn coordinator, within two vertical and parallel black lines.

Altitude (Height) readouts have a similar form to those for airspeed but are positioned on the right hand side of the screen. The vertical altitude tape and related numerals together with its triangular pointer gives you an analogue view of your altitude. Its associated digital readout of can be seen in the upper right region of the screen. To help in interpretation of all the numeric figures thousands of feet are displayed in larger numerals than are used for hundreds of feet (Viz: 12⁵ for 12500 feet). The current barometric setting is displayed immediately below the altitude tape and in the lower right hand corner of the screen.

An indication of vertical speed is given by a single line numeric readout of your current rate of climb or descent. This is shown in either the left or right hand display areas outlined in figure one above according to your preference. If you are gaining altitude an up arrow is used on the right of the vertical speed value to give direction and conversely a down arrow is shown in this position for descent.

To assist you with flight management ‘Bugs’ may be set to mark your desired heading, airspeed or altitude. These are represented by a white triangular arrow for heading and a similar black arrow for each of airspeed and altitude. All are centred in the appropriate moving bar at the desired location and move together with the tape. If the preset position of the bug is not able to be shown within the viewable area, the arrow will be positioned at that end of the tape closest to the desired value.

A digital clock or alternatively an up/down timer can be selectively displayed in the lower left-hand corner of the screen

A digital voltmeter showing information corresponding to the electrical power supplies available at the EFIS can be selectively presented in either the left or right hand display areas outlined in figure one above. Up to three rows of data can be displayed. The first row labelled ‘M’ is the main aircraft bus voltage. In the second row, labelled "E", is the voltage of an optional external battery. On the lower line, labelled "I", is the voltage of an optional internal battery.

Measurements of the vertical acceleration (g) experienced by the EFIS-D10A can be selectively displayed in either the left or right hand display areas outlined in figure one above. Three rows of text make up the ‘g meter’. The top row, labelled ‘MX’, gives the value of maximum positive acceleration since resetting the meter. The middle row, labelled ‘CR’, is the current g level. On the bottom line, labelled ‘MN’, is the minimum acceleration which can also be regarded as the maximum negative g experienced by the EFIS-D10A since reset.

The user control interface to all the commonly used functions in the EFIS such as: power on/off; setting of altimeter barometric pressure; ‘Bugs’ for heading, airspeed and altitude; time of day clock and elapsed time counter; display dimming; and access to checklists - is a row of six push buttons located along the bottom facing edge of the front panel. A menu system is also provided to assist in using these controls although this is not displayed constantly. Nevertheless, this can be easily and quickly brought up by pressing any one of the buttons. The menu is designed to take up a minimum amount of space on the screen and especially not to interfere with the important flight information whilst being intuitive in use.

Various safety features are built in the EFIS operation to aid recovery from unusual flight conditions. For example, if the power is switched off whilst in level flight and you then enter a climb and turn, during which, the EFIS-D10A is switched on again. The EFIS-D10A will, as a result of microprocessor computation using all the sensory inputs and within 10 seconds, indicate accurately that you are in the climb and turn. In addition, if you were to carry out an exceptionally rapid manoeuvre (over 150 degrees/second!), so that the sensors become saturated, the EFIS-D10A will advise this condition by displaying the caption "Attitude Indeterminate". You are also alerted to this abnormal situation by the use of a grey tone instead of multicoloured display. The screen will nevertheless continue to present the basic orientation information correctly.

Upon recovering to normal flight, of less than ±30 degrees of level and a rate one turn, the EFIS-D10A will in within five seconds resume with a full and accurate information display. It is important to note that saturation of the sensors in this way will only effect the attitude display and all other readings remain accurate throughout.

To further enhance flight safety and help accommodate loss of the aircraft electrical supply the DYNON EFIS-D10A can be optionally supplied with a factory fitted internal long life lithium ion rechargeable battery. If fitted, this option also includes a means of managing the battery charge state whilst the EFIS is in normal operation and deriving power from the aircraft main electrical supply. The system will also alert you with a visual on the screen warning when the charge state of the battery is low. In the event of a loss of aircraft power a properly maintained and fully charged battery give a minimum of two hours of use in full operational mode.

Other options that can be supplied for operation with this EFIS are systems for indication of AOT (Outside Air Temperature), AOA (Angle Of Attack), true airspeed, and density altitude and for the remote sensing of compass information. These features will often require the fitting of hull mounted equipment and subsequent calibration of the function. Details of which can be supplied by DYNON AVIONICS and it’s agencies.

Figure 2

Power Supply 10v to 30v

Nominal Power Consumption 2 watts

Initial battery charge Demand 20 watts

Note:

Figure 3

Basic Weight 1 lb 9 oz

With Battery Weight 1 lb 15 oz

Overall Height 3.39 inch (86mm)

Overall Width 4.09 inch (90mm)

Overall Depth 6.85 inch (174mm)

Instrument Panel Fitting Standard 3⅛ inch instrument hole

In a normal installation the screen portion of the instrument protrudes approximately a ½ inch (12.5mm) proud of the instrument panel face. If required or preferred there is an optional mounting bracket to allow for a flush fitting with the instrument panel face.

Figure 4