REASON FOR REVISION: Revised item 1 on page 1. Revised note at the end of Section III. Revised the LED Codes for all EIS part numbers in Table 1. Revised item 5 in Section V. Revised NOTICE after item 5 in Section V. Revised Section VI to delete reference to SB 311 and add a Drive Gear Inspection procedure. Revised: NOTICE in Section X. Added Lycoming part numbers in Section X. Revised manifold pressure port inspection in Section XVI. Added Testing to Section.

Incomplete review of all the information in this document can cause errors. Read the entire Service Instruction to make sure you have a complete understanding of the requirements.

This Service Instruction provides guidance to remove existing Magneto Type Ignition System and the installation and troubleshooting of the Lycoming Electronic Ignition System (EIS).

This Service Instruction, as a standalone document, only provides sufficient approved data for the engine alteration. A subsequent airframe alteration is required when engines modified per this SI are installed into an airframe and connected to the airframe electrical system. The airframe electrical diagrams in this SI are only provided for information and do not constitute an airframe installation approval.

Lycoming recommends that operators and mechanics interested in the installation of Lycoming EIS, review this document and make appropriate decisions prior to beginning any work. These decisions will aid in ordering the appropriate EIS units and help facilitate the return-to-service documentation.

At the engine level, an EIS may be installed replacing one or both of the engine’s traditional magnetos as a minor alteration documented with an engine logbook entry. Current FAA guidance is that the required airframe electrical system alterations needed for a single EIS installation may be accomplished by either minor or major alteration. The installer can decide which type of alteration is best for their application. Lycoming is providing the following recommendations based on this guidance.

  • If the installer considers the airframe alteration a minor alteration, this Service Instruction, FAA Advisory Circular 43.13-1B and 2B, and other Advisory Circulars or applicable information can be referenced in the airframe logbook as acceptable data.
  • If the installer considers the airframe alteration a major alteration requiring an FAA Form 337, this Service Instruction, specific sections, chapters, and paragraphs used from FAA Advisory Circular 43.13-1B and 2B, and other approved instructions can be referenced in Block 8 of the Form 337 as approved data along with the appropriate airframe logbook entry. If the installer does not have sufficient approved data to substantiate the alteration, they should obtain approval of their acceptable data by an Aviation Safety Inspector (field approval) or appropriately rated Designated Engineering Representative.

Replacing both magnetos with two EIS units is considered a major alteration that is a major change to the type design at the airframe level and would require an airframe type certificate, amended type certificate, or supplemental type certificate approval. When running dual EIS, the second EIS must be connected to a backup power source independent from the aircraft’s electrical system. A backup battery system such as the TCW Technologies™ Integrated Back-up Battery System has been evaluated by Lycoming and found to be acceptable for this requirement.

Refer to Table 1 to select the correct EIS to replace the currently installed magneto(s). Correct EIS depends on whether the magneto(s) being replaced are 4 or 6-cylinder, plain drive or impulse coupled, and the base ignition timing of the engine. Refer to the latest revision of Lycoming Service Instruction 1443 for EIS part numbers. Contact a Lycoming Authorized Distributor to order EIS Modules.

I. General Description

The Lycoming Electronic Ignition System (EIS) is a magneto replacement for 4 and 6-cylinder Lycoming piston aircraft engine.

The EIS is designed to use existing aviation spark plugs gapped to OEM specifications.

The EIS is designed to use a “Slick” style ignition harness. If replacing a “Slick” magneto, the existing serviceable harness may be re-used. If replacing any other magneto, or for a new installation, an approved “Slick” style ignition harness is needed. Although not required, Lycoming recommends installing a new harness when installing an EIS.

II. Technical References

The following documents may be referenced during the installation of the EIS:

  1. Lycoming EIS Installation Instructions: SI 1569 (this document).
  2. The latest revision of Lycoming Service Instruction SI 1443.
  3. FAA Advisory Circular 43.13-1B and AC 43.13-2B Acceptable Methods, Techniques, and Practices.
  4. Instructions for TCW Technologies ™ Integrated Back-up Battery System (if using this battery).

III. Component List

LYCOMING OFFERS THREE MODELS OF THE ELECTRONIC IGNITION SYSTEM. CAREFULLY REVIEW THE FOLLOWING INFORMATION TO DETERMINE THE APPROPRIATE SYSTEM FOR YOUR ENGINE. REFER TO TABLE 1 OF THIS SERVICE INSTRUCTION FOR APPROPRIATE PART NUMBER.

66K4A – 4 Cylinder Lycoming Non-Impulse Magneto Replacement

The following items are needed to install the 66K4A to an engine:

  1. Lycoming Ignition Module: 66K4A (refer to the latest revision of Lycoming Service Instruction SI 1443 for EIS part numbers applicable to your engine),
  2. 66K4A Hardware Kit (included with EIS Module),
  3. These installation instructions: SI 1569 (available at www.Lycoming.com).

66K4F – 4 Cylinder Lycoming Impulse Magneto Replacement

The following items are needed to install the 66K4F to an engine:

  1. Lycoming Ignition Module: 66K4F (refer to the latest revision of Lycoming Service Instruction SI 1443 for EIS part numbers applicable to your engine),
  2. 66K4F Hardware Kit (included with EIS Module),
  3. These installation instructions: SI 1569 (available at www.Lycoming.com). 66K6D – 6 Cylinder Lycoming Magneto Replacement

The following items are needed to install the 66K6D to an engine:

  1. Lycoming Ignition Module: 66K6D (refer to the latest revision of Lycoming Service Instruction SI 1443 for EIS part numbers applicable to your engine),
  2. 66K6D Hardware Kit (included with EIS Module),
  3. These installation instructions: SI 1569 (available at www.Lycoming.com). Please contact Lycoming if any items are found damaged or missing.

IV. Preparation

  1. Find the data-plate on the engine and note the timing value and rotational direction (L or R) listed for the magneto being replaced.
  2. Find the matching engine timing value in the table 1 below.