Aviation Maintenance, FAA, and Designees

Aviation Maintenance, FAA, and Designees

For anyone working in the aviation field, it should be no shock that the role FAA plays in our industry has changed over the last several years. The trend started decades ago with the pilot community when FAA no longer provided check rides and written tests, in favor of transferring those activities to persons “Designated” by the Administrator. That practice has evolved to the point where most FAA offices no longer provide services that we (and our customers) have expected in the past and quite frankly have taken for granted as things FAA should be providing. Services like the issuance of Airworthiness Certificates, Ferry Permits, Field Approvals and many others are no longer being provided by the various FAA offices and instead, FAA is referring maintenance providers to Designees for those services.

When it comes to Technical Designees, there are several. The regulatory authority for designations comes from 14 CFR §183. That group of regulations covers all designees, but on the technical side there are Designated Mechanic Examiners (DME), Designated Parachute Rigger Examiners (DPRE), Designated Aircraft Maintenance Inspector (DAMI), Designated Engineering Representative (DER), Designated Manufacturing Inspection Representative (DMIR), Designated Airworthiness Representative (DAR), and Organization Designation Authorization (ODA). For our discussion, we can eliminate the DPRE, as most of us aren’t dealing with parachutes, the DME since we pretty much all worked with one of them when we got our A&P certificates, The DAMI since they are only involved with military flying clubs overseas, and the DMIR as they are most often associated with facilities that have Production Certificates and build airplanes. We will also leave out the ODA as these are organizations, and not individuals.

This leaves us with DERs and DARs. As the titles imply, a DER is most commonly associated with Engineering, or more correctly, the approval of engineering documentation, and observing testing to verify engineering analysis, and the DAR is most commonly associated with the issuance of Airworthiness Certificates. As you may have guessed, within the system of designees, there is nothing that is simple! DERs and DARs all have limitations on what they can do, and each has a “Letter of Authorization” (LOA) that outlines what authorizations they have and the types of aircraft they can apply those authorizations to.


The majority of DERs work on TC and STC type projects. They are the focal point in approving the engineering documentation developed during a project to get an aircraft, engine, or propeller Type Certificated, or to get a specific modification to an aircraft, engine or propeller STCd. A subset of the DERs have what is known as Repair or Alteration Authority. These are the DERs that can help make your life easier. But wait, not all DERs can approve data for all things. DERs are broken up by specialty. These specialties are Structures, Powerplant Installations, Mechanical Equipment, Electrical Equipment, Radios, Engines, Propellers, Flight Analyst, Flight Test Pilot, and Acoustical. These groups are further broken down into subcategories, so it will likely take some research to find the right combination of DERs to provide approval for all the data necessary for a given alteration or repair. Remember, you only need approved data for Major Alteration and Major Repairs, and within the DER handbook (Order 8110.37) DERs are expressly prohibited from providing approval for minor alteration and minor repairs. DERs (in the capacity of DER) only approve data. The data they approve can come from any source. When a DER generates that data, he isn’t functioning as a DER, but as an Engineering Consultant. You as a mechanic, or your client can provide the engineering data if you have the expertise to do so.


There are two different kinds of DARs, Manufacturing DARs and Maintenance DARs. Unless you are working with an STC project, or another project where things are being produced, it is unlikely you will need a Manufacturing DAR (DARf). Typically, they provide Conformity Inspections and Initial Certifications. Working in the maintenance side of things, it is much more likely that you will have need of a Maintenance DAR (DARt). The maintenance DAR provides what are known as Recurrent Certifications. This can be as simple as replacing a lost Airworthiness Certificate, or as complex as exporting or importing aircraft, engines, propellers, or parts. Certain DARt’s have authority to provide Field Approvals just as an FAA Safety Inspector does (Make a notation in Block 3 of the FAA Form 337 approving the data shown in Block 8). Like the DER, all DARs have limitations on what functions they can perform, and those functions are identified in their LOA. These are limited by Function Code (defined in Order 8000.95), and further limited as the specific managing FAA office defines. DARs are limited geographically to their managing office and need special authorization to work “out of district”.

Major Repair and Major Alterations

As maintenance providers, your primary contact with Designees will be to support Major Repair and Major Alterations on your client’s aircraft. To that end, defining Major Repairs and Major Alterations correctly is paramount. All too often, the mechanic working a project will simply throw up his hands and say “This is a Major Repair, or Major Alteration” without fully researching if it truly is Major! There are several source documents to help make that decision. 14 CFR §1.1, and §43 Appendix A are the starting point. That said, the best two references are AC43-210A and Order 8300.16A. Both of these documents have flow charts that are very similar that will walk you through the decision process of a) is this a Major Alteration / Major Repair, or is it a Minor Alteration / Minor Repair. It will further define the type of Data that will be required – can it be done with Engineering Data, Field Approval, or will it require an STC. When working through either flow chart, if you answer the questions accurately, many alterations or repairs that you may have thought were major are actually minor and can be done with acceptable data and returned to service with only a log book entry. A good practice to use would be to document your decision logic based on these flow charts in the log book so even if the decisions are questioned, the log entry shows that you did due diligence in making the decision. An additional document to refer to when making the Minor/Major decision and helping to determine the level of certification needed is the AFS-300 Major Repair and Alteration Data Approval Job Aid. This document can be found on the FAA FSIMS web site. Once a repair or Alteration are determined to be Major, the next step is getting the required Approved Data. Order 8300.16 outlines what previously approved data may exist. The AFS-300 Job Aid identifies if a repair or alteration can be done via Field Approval (DAR) or DER approval (DER), or if it will require an STC (Processed through the FAA Aircraft Certification Office).

The next action that require research is the development of a Certification Checklist. AC43-210 provides a brief description of how to do this, but start with the Certification Basis for the aircraft in question. This can be found on the TCDS for the aircraft. Using that Certification Basis, identify every regulation within that Certification Basis that the specific repair or alteration will or may change the way compliance was shown by the original TC holder, and determine how you will show compliance to that regulation with your repair or alteration. If you are using DERs to support the project, that Certification Checklist determines what specialties the DERs will need to complete the project. For all Major Repairs and Major Alterations, the aircraft will need to at least meet the original Certification Basis, and in some cases, may need to meet some more recent regulatory requirements. Keep in mind that you, as a mechanic can perform most of this research, or you can hire a DER or DAR to do the research for your client. If using DER approvals, before you sign block 7 on the 337, it is your responsibility to ensure that all items on the certification checklist have been resolved. Have all the required Approved Data before starting the project. Many aircraft have had alterations started, only to find that the scope of the alteration requires an STC. A typical STC will take over 2 years to complete and could cost in the hundreds of thousands of dollars in engineering and testing. Don’t start cutting metal until you have the approved data!

Other DAR Services

Your clients may ask your advice on aircraft purchases and aircraft sales. If any of these transactions involve international transactions, get a DAR involved early! There are specific steps that need to happen in a precise order for these transactions to be successful. It may cost the client some money up front, but could save them significant time and money on the back end of the transaction.

Replacement Airworthiness Certificates are a constant issue. They get lost or mutilated from use. A DAR can issue a replacement Certificate relatively easily.

Many FSDOs will no longer issue Ferry Permits. Clients need to understand that when a DAR issues a Ferry Permit, the DAR has to physically inspect the aircraft. This usually involves travel expenses and time that will be billed to the client. The FAA has the option of issuing a FAX or Email Ferry Permits, the DAR does not have that option. Compounding this is the fact that the DAR (while also being an A&P) is prevented, by policy, from making any necessary repairs to the aircraft prior to determining that it is “safe for the intended flight” so an A&P will likely need to go to where the aircraft is located to make any temporary repairs.

Designees can provide significant technical support in the course of aviation maintenance and client services. Unfortunately, many of those services were viewed as free from the FAA in the past, but Designees earn their living by providing those services. Another advantage of using Designees is the ability to discuss proposed projects without direct interaction with FAA. The Designee is responsible for those FAA interactions, and in many cases can provide guidance on how to satisfy the regulatory requirements that you may not have considered.

David Schober is an A&P, IA and Vintage Aircraft DER. He has been an airline director of training, president of a Part 135 charter operation, DOM of a 145 repair station and is currently working with the Department of Navy supporting their fleet of commercial deriviative aicraft.

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