SIGMA-TEK 4000B / 4000HR SERIES STANDARD
DIRECTIONAL GYRO

The 4000B is our standard air-driven directional gyro. As the aircraft turns left or right, gears on the sensing unit and dial shaft translate this rotation into rotation of the instrument’s vertical dial. Left turns produce clockwise dial rotation and right turns produce counter-clockwise rotation. The gyro is controlled by a heading selector knob located on the lower left of the instrument. Pressing and turning the knob first disengages the dial shaft and then resets the dial to a new heading, which results in a new course indication. Releasing the selector knob re-engages the dial shaft. The on-course position of the pointer is always at the top of the azimuth circle (0° on the dial with the aircraft headed north).

The 4000HR air-driven directional gyro offers some of the best features of our other popular models. It inherited all of the functionality and reliability of the industry standard 4000B upon which it’s based, and it picked up a heading reference bug from the 4000C autopilot model.

Many pilots find the heading reminder a valuable feature whenever the cockpit is busy, such as during an approach with heavy ATC traffic. Setting a new heading during a long, cross-country flight eliminates the tedious math associated with frequent navigational crosschecks. A quick glance at the instrument instantly reminds the pilot of his heading. The heading bug can be positioned anywhere around the heading card by turning the right knob.

The Standard configuration can replace most air driven gyros with the major difference being in the layout and colors of the display.

NOTE: Lighted instruments do not include lamp trays, please see accessories to purchase separately.