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SLSA: Major Repairs & Alterations

Learning and Understanding This New World Could Save Owners and Maintenance Personnel Huge Headaches in the Future.

There have been multiple questions from mechanics and S-LSA owners about proper documentation and authorization for major repairs and alterations in the field. If you are confused, you are not alone. The Light Sport Rule is relatively new and was a large, sweeping change in the regulations. There is a lot to learn and understand. Additionally, S-LSA aircraft must comply with consensus standards, as well as Federal Aviation Regulations.

What Are Consensus Standards?

Consensus Standards are industry-developed standards that apply to aircraft design, production, and airworthiness. They are accepted by the FAA for the purpose of certificating light sport aircraft.

The continued airworthiness of S-LSA are governed by these standards, which are copyright protected and can only be purchased from ASTM International ( All regulatory bodies and manufacturers must purchase their own copy of the standards, read, and interpret them. The aircraft must be maintained to these industry-developed standards, meet FAR Part 43 requirements, and comply with manufacturers’ safety directives and FAA Airworthiness Directives applicable to Type Certificated (TC) products installed on the aircraft.

S-LSA Maintenance Manuals

ASTM standards require that all S-LSA have maintenance manuals. The maintenance manual must lay out what level of maintenance technician certification is required to do a particular task and provide detailed instruction to complete the task. If a task is not in the manual, you cannot complete it without special manufacturer authorization. There is a huge difference in the quality and completeness of manuals provided by the S-LSA manufacturers. But the manufacturer’s maintenance manuals must be your source of what you can and cannot do. If it is not in the manual, you cannot do it without a Letter of Authorization, as explained next.

What Documentation is Required?

For an S-LSA, the aircraft manufacturer must approve any modification including installation of new avionics. The manufacturer also determines what is a major repair or major alteration. In order to discuss a major repair and alteration on an S-LSA, we should start by looking at the ASTM standards and a few regulations in place for this specific category.

The definition of a major repair or alteration for an S-LSA was required to be included in the ASTM standards by the FAA and is documented in the preamble of the final rule. ASTM defined the terms in ASTM F2483 as follows:

3.1.10 major repair, alteration, or maintenance -- any repair, alteration, or maintenance for which instructions to complete the task excluded from the maintenance manual(s) supplied to the consumer are considered major.

3.1.11 manufacturer -- any entity engaged in the production of an LSA or component used on an LSA.

3.1.12 minor repair, alteration, or maintenance -- any repair, alteration, or maintenance for which instructions provided for in the maintenance manual(s) supplied to the consumer of the product are considered minor.

9.2 The manufacturer or other entity that performs the evaluation of an alteration or repair shall provide a written affidavit that the aircraft being altered will still meet the requirements of the applicable ASTM design and performance specification subsequent to the alteration.

9.3 The manufacturer or other entity that performs the evaluation shall provide written instructions and diagrams on how, who, and the level of certification needed to perform the alteration or repair.

9.3.1 The instructions must include ground and flight testing that complies with the original ASTM production acceptance testing standard, as appropriate, to verify the alteration was performed correctly and the aircraft is in a condition for safe operation.

9.4 The manufacturer or other entity that performs the evaluation shall provide information to the owner of the aircraft for the documentation of the alteration in the aircraft’s records.

AC 65-32

306.a. Maintenance and Alterations.

Any maintenance or alteration that is performed on an S-LSA must be accomplished using data supplied by the manufacturer and performed by a repairman (light-sport aircraft) with a maintenance rating, a mechanic with an airframe and powerplant rating, or a repair station appropriately certificated for that class of S-LSA in accordance with part 43.

So, what documentation is required to be in the aircraft records for any major change or alteration? The manufacturer is required to provide:

1. Directions to accomplish the task.
2. Detailed instructions and diagrams as needed to perform the task.
3. A method to test/inspect to verify the task was accomplished properly.
4. An affidavit stating that the modification, repair or alteration will not change the aircraft flight characteristics.

It is not uncommon for manufacturers in the S-LSA industry to send incomplete letters of authorization; many offer authorization by phone. When this happens, the maintenance technician must ask for these authorizations in writing and resubmit any authorization that is incomplete.

Who Is The Manufacturer?

Many S-LSA are manufactured in other countries and have U.S. distributors. So the common question is: Can a distributor authorize a change? The regulations are clear (Reference 91.327 (a) (5), (6) and (7)) that any modification after the date of manufacture must be authorized by the manufacturer, inspected by procedures developed by the manufacturer and recorded in the specific aircraft records. The FAA considers the manufacturer as the entity that attests to compliance with the ASTM standards on the FAA form 8130-15. Further, the ASTM Quality Assurance Standard F2279 requires that the person signing compliance with the ASTM standards be specifically identified in the manufacturer’s Quality Assurance manual and that the approval be accomplished in accordance with a documented system/procedure that assures that the aircraft continues to comply with all the applicable ASTM standards.

Who Can Perform A Major Repair or Alteration?

ASTM F2483 9.3 states that the manufacturer must identify in writing the instructions for the modification, who is authorized to perform the modification, and the level of technician certification that person must have. The person performing the repairs must also have had training or experience in performing that task previously.

9.3 The manufacturer or other entity that performs the evaluation shall provide written instructions and diagrams on how, who, and the level of certification needed to perform the alteration or repair.

FAA Advisory Circular 65-32:

Major repairs and major alterationsmay only be accomplished on S-LSA by a repairman (light-sport aircraft) with a maintenance rating, a certificated mechanic with A&P ratings, or a certificated repair station.

The manufacturer must provide the technical data for such a repair or alteration and identify the training required, if any, to perform that repair or alteration.  . .Before making any major repair as per the consensus standard, a repairman (light-sport aircraft) with a maintenance rating, a mechanic with an airframe and powerplant rating, or appropriately certificated repair station, must receive training to perform the repair.

This training should be from either the manufacturer or from an industry accepted training provider.

The ASTM consensus standard specifies that the manufacturer of the aircraft shall determine what is a major repair and major alteration. The same consensus standard requires the manufacturer to determine what additional training is required for the Light Sport Repairman with a Maintenance Rating (LSRM) to be qualified to perform those tasks. The LSRM should contact the manufacturer to determine if the major repair or major alteration is authorized and determine if additional training is needed.

Can an A&P Perform Major Repairs on S-LSA?

It is up to each manufacturer to dictate who can and who cannot do work on your S-LSA. If the authorization for a major repair or alteration allows an A & P to complete a major repair, the mechanic must remember that when working on S-LSA, the aircraft’s consensus standard, maintenance manual, and instructions for continued airworthiness must be used instead TC data.

Furthermore, on special light sport aircraft, both Part 43 and the general privileges and limitations of FAR section 65.81, still apply. To satisfy the requirements of § 65.81, the mechanic must be able to prove to an FAA inspector that he or she performed that work at an earlier date, was trained to do the work, or was supervised by another mechanic or repairman performing that task.

The Rotax 912 is by far the most popular engine used in most S-LSAs. The real problem is that an A&P mechanic is required to have Rotax factory training to perform any work on Rotax engines.

These mechanics are not allowed to service or maintain an engine on an S-LSA, unless appropriately trained to do so. As of this writing, there are still relatively few mechanics approved to work on the Rotax 912 in the U.S. In order to add new equipment (or to modify anything) on an S-LSA, the maintenance technician or owner of the S-LSA must make a specific request to the manufacturer. It is completely up to the manufacturer to allow anyone to install the equipment (or make the modification).

There is no FAA involvement. If the manufacturer allows an owner to install avionics under the supervision of a mechanic, it is important to note that this must be an A&P since a LSRM cannot supervise.

If your S-LSA has a type certificated engine or Technical Standards Order (TSO) product installed, major repairs and major alterations on these FAA-approved products will require compliance with the recording requirements to document such changes contained in Part 43.

The bottom line is that the term “major repair” means any task which is excluded from the manufacturer’s maintenance manual. If the task is not in the manual, you must request written authorization from the manufacturer.

For an S-LSA, any modifications or major repairs must be approved in writing. This includes installation of new avionics or any propeller changes. Finally, all documentation must be included in the logbook records.

For more information or to inquire about the Light Sport Repairman Training course, contact Rainbow Aviation Services or visit

F2339-06(2009) F2483-05 Standard Practice for Maintenance
and the Development of Maintenance Manuals for
Light Sport Aircraft/ ASTM International, West Conshohocken,
PA, 2009,
F 2279 Standard Practice for Quality Assurance in the Manufacture
of Fixed-Wing Light Sport Aircraft LSA / ASTM International,
West Conshohocken, PA, 2009,
AC65-32 – Certification of Repairman (Light-Sport Aircraft), click Advisory Circular and search
LSA Repairman Certificate: eligibility, privileges and limits
14 CFR section 65.107
Order 8130.2F - Airworthiness Certification of Aircraft and
Related Products,
To view article in the original zmag publication, click below link:

Light Aviation Edition November 2009