SIGMATEK 3-1/8" DG 4000B 30

Part# 4000B
MFR Model# 1U262-001-39
Sigma-TekModelAirplane ColorIndex MarkersDial @ 30 degreesLetters @ 90 DegreesLightedHeading
Part Number


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 instrumentís 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 (0į 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 itís 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.
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adjustment knob does not operate easily.

Dave M
July 15, 2020


Please note, Aircraft Spruce's personnel are not certified aircraft mechanics and can only provide general support and ideas, which should not be relied upon or implemented in lieu of consulting an A&P or other qualified technician. Aircraft Spruce assumes no responsibility or liability for any issue or problem which may arise from any repair, modification or other work done from this knowledge base. Any product eligibility information provided here is based on general application guides and we recommend always referring to your specific aircraft parts manual, the parts manufacturer or consulting with a qualified mechanic.

Q: Are the Sigma-Tek 4000B / 4000HR Series Directional Gyros suitable for use in Type Certified aircraft such as a C172?

The Sigma-Tek 4000B / 4000HR Series Directional Gyros are TSO'D and suitable for certified airplanes.

Q: Are the Sigma-Tek 4000B / 4000HR Series Directional Gyros suitable for use in Type Certified aircraft such as a PA28-161?

Yes, these Sigma Tek gyros are FAA TSO Approved for use in certified aircraft.

Q: What is the overall length of the Sigma-Tek 4000B / 4000 HR series DGs?

Dimensions are:
Height: 3.25"
Width: 3.38"
Depth: 6.68" (max)

Q: Is this DG a 3 Pin or 5 Pin connector?

These Sigma Tek DGs have a connector on the back. It has two ports for air inlet and vacuum.

Q: Does this sigmatek overhauled instrument include form 8130 for installation in certified aircraft? thanks

8130 is not included with this instrument. It can be requested at time of order, additional charges will apply.

Q: I am a lab technician from Ecole Nationale Aerotechnique. I am trying to do an overhaul for a Directional gyro used in the school lab, PN 1U262-001-39. I saw the price on your website is 1109 each + 517 core exchange charge. Do I need to return my gyro to you? Do I need to pay the core exchange charge if I return my gyro to you ? And how does the process work? Looking forward to your answer. Thank you very much.

Yes, the core charge is billed upfront with the purchase of the gyro. When you return your old gyro the core charge is refunded to you. You will receive an RMA in the box to send back your old gyro for core credit.

Q: Would 4000HR-2 fit as a replacement for a 4000B-26, specifically its physical characteristics, are they the same?

Physically these are the same size, however, the airplane color and display will be different. 4000HR series are different colors schemes.

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