Trutrak Flight Systems EFIS AP III

Consider first the pitch display. Motion of the pitch display short term is gyroscopic as it must be to fly in IMC. Long term it is VSI. This display has two distinct advantages, the first being that it provides an instantaneous vertical speed presentation. The second is that when the reference airplane is on the horizon the aircraft is neither climbing nor descending. This eliminates the need for adjusting the position of the pitch reference airplane to compensate for the angle the fuselage is flying. The resulting benefit of the concept is that it makes holding altitude easier.

The HSI is placed below the horizon as in the larger more expensive displays. It is in the form of an ellipse for two reasons. First, an ellipse when compared with a circle of the same height provides a broader scale at the top where it is read. Second, it looks as a circle would when laid out on the ground ahead of the aircraft. The boldness of the high quality display in combination with its location enhances the flyability of the overall instrument.

The analog presentations of airspeed and altitude are based on the belief that round is better. It will be noted that after having tried other presentations the automobile industry is back to round instruments. Nothing in the modern world of vertical tapes compares with the dynamic effect of a round altimeter dial rotating about a fixed pointer. As a target altitude is approached it is natural for the pilot to slow the needle velocity so as to arrive at the altitude without overshoot. Even though it is our belief that “Round is Better”, we have also given the user the option to use the rectangular airspeed and altimeter scales as well. This selection can be made at any time.

Within the bank angle scale, indicators are inserted, which show the angle for a standard rate turn. These indicators move outward on the bank angle scale as airspeed increases. Placed above the bank angle scale is an inclinometer that looks just like a conventional ball in a curved tube.

Still another convenient feature is the optional presentation of important engine data, in the pilot’s direct field of vision, displayed across the top of the instrument.

A flight director is standard even in the basic flight instrument. Like Trutrak's autopilots, when the power setting is not sufficient to comply with altitude or vertical speed commands, the flight director transitions to an airspeed mode in which airspeed is held at or above a minimum value pre-set to the specific aircraft. The result is the highest level of safety.

The automatic arrival transition is also included. This is a feature that will help even the experienced pilot when approaching an unfamiliar airport. To initiate the arrival transition click CRS – set the HSI course pointer to the selected runway direction – press APPR – using the flight director or autopilot, fly the arrival path to the selected runway.

EFIS:

• Airspeed
• Altimeter
• Artificial Horizon (Attitude, Vertical Speed Mode, Attitude + Vertical Speed Mode
• Directional Gyro
• Slip / Skid Ball
• Standard Rate Turn Indicator
• Single Cue Flight Director with Airspeed Limiting
• Adjustable Course Pointer
• Automatic Arrival Transition
• Heading Bug
• Altitude Bug
• Current Selected Waypoint
• Distance to Waypoint
• GPS CDI
• GPS VDI
• SL-30 CDI
• SL-30 VDI
• Airspeed Warning
• User-definable V-Speeds
• Round or Rectangular Airspeed and Altimeter
• Selectable Units
• GPS-slaved solid state DG
• Digital Ground Track Selector
• GPS Nav Mode
• Control wheel steering
• Altitude hold
• Climb and descend on vertical speed
• Trim sensing pitch servo that annunciate need for trim
• Altitude selector

Autopilot:

• Track Select Mode
• GPS Nav Mode
• Altitude Hold
• Altitude Select
• VS Select Mode
• Pitch Trim Annunciation
• Control Wheel Steering