When someone says a repair is “DER approved,” it is worth knowing exactly what was approved, by whom, and what that approval does and does not cover. The short answer is that an engineer authorized by the FAA reviewed a package of technical data and found it compliant with the airworthiness standards — and documented that finding on a specific form. This article walks the approval path from engineering substantiation to the signed FAA Form 8110-3, and clears up a point that trips up a lot of buyers: what that form actually approves.

The Approval Path in Plain English

A DER repair starts as an engineering problem, not a paperwork problem. Someone has a component that is worn, damaged, or out of limits, and the question is whether it can be restored to an approved condition by a defined process. Answering that question takes substantiation: analysis, testing, material and process specifications, dimensional limits, inspection criteria, and a repair procedure detailed enough that a shop can execute it and an inspector can verify it. Together these form the technical data package that defines the repair.

That package is then reviewed by a Designated Engineering Representative — an individual engineer the FAA has authorized under 14 CFR Part 183 to make compliance findings within a specialty such as structures, powerplant, or systems and equipment. (Members of an Organization Designation Authorization unit hold comparable authority inside an approved organization.) The DER examines the data against the applicable airworthiness standards. When the data supports it, the DER approves the engineering data — and records that determination on FAA Form 8110-3.

What FAA Form 8110-3 Actually Approves

Here is the point to internalize: FAA Form 8110-3 approves data. It is the Statement of Compliance with Airworthiness Standards, the means by which a DER approves, or recommends approval of, engineering and technical data. It documents a finding — that the repair data shown complies with the standards. That is its entire job.

It is worth being just as clear about what the form does not do. An 8110-3 is not a production approval, so it does not authorize anyone to manufacture parts. It is not an operational approval, so it does not clear an operator to fly anything. And it is not a work order — it does not direct or authorize the physical labor of repairing a specific component. The form sits at the engineering layer. The FAA’s guidance on the form and the DER Handbook (Order 8110.37) treat it as a compliance record for data across project types including type certificates, PMA, major repairs, and major alterations. Reading the paperwork correctly means not assuming it says more than it does. The way the pieces fit together on the shop floor is covered in DER repair documentation.

Major vs. Minor: Why the Distinction Drives the Whole Process

Whether a repair even needs approved data depends on how it is classified, and that classification comes from 14 CFR Part 43, Appendix A, which defines major repairs and major alterations. A major repair is, broadly, one that could appreciably affect weight, balance, structural strength, performance, powerplant operation, or other qualities affecting airworthiness if done improperly — repairs to primary structure, engine components, and landing gear typically fall here. A minor repair is everything else.

The distinction matters because a DER repair approval is fundamentally about supplying approved data for a major repair. Minor repairs can generally be accomplished using acceptable data and do not require this route. Major repairs need approved data, and a DER’s finding of compliance on an 8110-3 is one recognized way to produce it. That is why the major/minor line, buried in an appendix, quietly determines whether the whole DER process is in play. Which components are realistic candidates is the subject of what can be DER repaired.

Three Forms of Repair Approval

Not every DER repair approval has the same reach, and the difference is captured in how the 8110-3 is scoped. There are three common forms, and knowing which one you hold tells you how far it travels.

A one-time repair approves the data for a single repair on a single component. It is the narrowest form — substantiated for this instance and no further. A serial-number-specific approval covers a named component by serial number; it is tied to identified hardware rather than to a class of parts. The broadest form is a multiple-use approval supporting a Repair Specification, or RS — standardized, step-by-step instructions for a recurring major repair that can be applied again and again to eligible components. An RS is not issued by the design approval holder and is not tied to specific serial numbers, which is what lets it serve as a repeatable, shelf-ready procedure.

The engineers who develop and approve these repeatable procedures are sometimes called RS-DERs, and the population of independent RS-DERs is limited. That scarcity is one real-world constraint on how quickly recurring major-repair approvals can be developed — worth factoring into any plan that depends on a fresh RS rather than an existing one.

From Approved Data to a Part Back on Wing

Approving the data is only half the story, and it is deliberately separated from the other half. Once the repair data is approved, the physical work is performed and the article is returned to service under 14 CFR Part 43 by an appropriately rated repair station or mechanic, following the approved procedure. The airworthiness standard the finished repair has to meet is the Part 43 standard: the item must be restored to a condition at least equal to its original or properly altered condition. When the repaired article is released, an FAA Form 8130-3 can accompany it as the airworthiness release.

FAA-approved life limits established by the type or production certificate holder do not change because a component was DER repaired; they remain in force, and life-limited parts are handled with corresponding care. The repair restores condition — it does not reset the clock. Holders of major-repair approvals also carry continued operational safety obligations, monitoring in-service experience and responding if an issue emerges. A DER repair, in other words, is not a one-and-done signature; it is an approved basis that someone stands behind over the life of the part. It is one of several disciplined aftermarket routes, discussed further in our repairs overview.

How AviaFix Approaches DER Repair Approval

AviaFix treats the data package as the product. Before a repair is offered, the engineering substantiation has to support a clean compliance finding, the approval form has to match the intended use — one-time, serial-specific, or a Repair Specification — and the records have to be assembled so a receiving inspector can accept the returned article without a follow-up call. We would rather decline a repair we cannot substantiate than defend a thin data package after the fact. A DER repair is an approved, competing source that meets the same airworthiness standard as any other route, and the discipline behind the paperwork is how that standard is kept honest.

Frequently Asked Questions

What does FAA Form 8110-3 actually approve? It approves engineering and technical data. The form is a DER’s documented finding that the repair data complies with the applicable airworthiness standards. It is not a production approval, not an operational approval, and not a work order — it certifies the data, and the physical work is handled separately under 14 CFR Part 43.

Does every repair need a DER and an 8110-3? No. Only major repairs, as defined in 14 CFR Part 43, Appendix A, require approved data, and a DER’s 8110-3 is one route to that data. Minor repairs can generally be accomplished with acceptable data and do not need this path. The major-versus-minor classification is what determines whether the DER process applies at all.

What is the difference between a one-time repair and a Repair Specification? A one-time repair approves the data for a single repair on a single component. A Repair Specification (RS) is a multiple-use approval — standardized instructions for a recurring major repair that can be applied to eligible components again and again, without being tied to specific serial numbers. Between them sits the serial-number-specific approval, which covers named hardware by serial.

Who actually performs the repair after the data is approved? An appropriately rated repair station or mechanic performs the physical work and returns the article to service under 14 CFR Part 43, following the approved procedure. The finished repair must restore the item to a condition at least equal to its original or properly altered condition, and an FAA Form 8130-3 can accompany the released article.

Sources & Further Reading

Related reading: What Is a DER Repair? · DER Repair Paperwork · Repairs overview

← All DER Insights