Sigma-Tek Directional Gyro 4000B-30

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New (Outright)New (Exchange)Factory Overhauled


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.

Core Exchange Notes:

Exchange core must be returned no later than 30 days from the invoice date to receive core credit.

Only like cores are accepted: Any 4000B series Sigma Tek core as exchange for a 4000B-30. Sigma-Tek must be on the nameplate.
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Item arrived in two days. It was very well packaged and marked fragile. It was in like new condition and included the necessary paperwork.

Gary W
May 2, 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: Can the Sigma-Tek Factory Overhauled DG's be mounted in a certified aircraft? If so, is there any issue with running it off a venturi?

This product is FAA approved and can be mounted in a certified aircraft. Per Sigma-Tek, while you can get it to work with off of a venturi and an inlet filter, they do not recommend this.

Q: Does this Sigma-Tek factory overhauled model 4000B-30 DG (part # 10-03359) have a 14v light?

No, the 4000B-30 is not a lit instrument.

Q: What is the core charge?

The core charge will automatically be added to the cart once this item is added to the shopping cart.

Q: Are these Sigma Tek 4000B gyros vacuum driven instruments?

Yes, this is a standard air-driven gyro.

Q: I routinely do aerobatics (Vans RV-8), involving Gs up to -1G to +4G. Is this an issue with this unit?

Per Sigma-Tek specifications the Maximum Acceleration is 1.5G's.

Q: How much is the core charge?

Current core charge is displayed when you add the item to the shopping cart. As of 9/20/19, it is $361.

Q: Is a 8130 form included with the Sigma Tek 4000B-3 overhauled unit?

Yes, it does. 8130-3 included in the box has dual (EASA) approval.

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