Designated Engineering Representatives Key Players in Aviation Maintenance

Deploying a DER repair can be the ultimate upcycling in aviation maintenance, sometimes becoming the difference between saving or scrapping a part.

A DER is a person designated by the FAA to approve major repairs and major alterations on behalf of the agency. [Credit: Shutterstock]

I was at the Wall Street Deli in Greensboro, North Carolina, about to tuck into a lovely Souvlaki platter when my phone buzzed on the counter before me. Yes, I answered it. Business always comes first when you are in aviation. It was my customer, Josh Brien, then procurement manager at Genesis Aviation, and he was hyperventilating. 

“Rick,” he said, “We have a problem.”

I was at his office door at 8 a.m. the following day. Brien ushered me into a conference room and set several pieces of metal—an anti-skid brake part for a Boeing MD-11— before me. Taking one in my hand, I looked up confidently at him. “This looks like a mission for a DER [designated engineering representative].”

“Is it legal?” Brien asked. 

Not only is it legal, but the repair is also FAA-approved and ships with a Form 8130-3 tag. Brien glanced up, smiled, and said, “Let’s write it up!’

What Is a DER?

The FAA is an enormous governmental institution with around 48,000 employees. Surprisingly, more is needed to manage all of the aviation responsibilities under its remit.

The agency often needs assistance finding that engineering data complies with the appropriate airworthiness standards, and it looks to designees, called designated engineering representatives, or DERs, and they can work for a company or act as a third-party contractor. The FAA engineering field office will appoint a DER to a specific technical discipline in their geographic region.

Why Use a DER Repair?

One reason DERs are necessary is because of the excess of used parts availability post COVID-19. The used serviceable material (USM) market is expected to reach $7.9 billion annually, according to management consulting firm Oliver Wyman.

The demand for USM is set to grow around 55 percent annually, according to Oliver Wyman. This material may be considered an alternative to solutions outlined by the OEM, such as parts manufacturer approval (PMA) parts and DER repairs.

How to Accomplish a DER Repair? 

In 2018 when I received the call from the procurement manager at Genesis Aviation, the cost of the anti-skid brake part (Meggitt part number 6000554 OEM) was $15,329 each. Aviall—now Boeing—was the exclusive distributor. As the sole supplier, it controlled the aftermarket and, at the time, quoted a seven-month lead time.

Airlines can't wait seven months for a part, much less one that costs more than $15,000 a pop. 

I contacted one of my shops, Fortner Engineering, and talked to Gary Fortner, the vice president of engineering. Fortner knew of the issue and the importance of viable spare parts, wrote a DER repair to reuse the housing and manufacture a new piston, saving countless piston-sleeve assemblies from the landfill and keeping a steady stream of product for the airline.

DER Misconceptions

To review, a DER is a person designated by the FAA to approve major repairs and major alterations on behalf of the agency, confirmed Debra Whittaker, engineering manager for Aerospace Coatings International. 

By this definition, a DER-approved repair should mean a major repair or alteration. However, most people refer to any non-OEM repair as a DER repair, which needs to be corrected. Repairs can be major or minor, but only major repairs require DER approval. Repair stations and operators can create their minor repair data without DER approval, Whittaker said. 

Here’s a Q&A with her about some aspects of DERs:

FLYING: What drives the decision to create or develop repair data for a unit?

Debra Whittaker (DW): Repairs are usually developed out of necessity because either the OEM did not address all possible maintenance activities in their CMM (component maintenance manual) or parts are unavailable. Repairs may also be needed to lower overall maintenance costs or to improve reliability. The two questions to answer are, can the unit be repaired and returned to an equivalent level of safety? And, is the lead time and cost of a repaired part less than that of a new piece?

FLYING: Can others utilize that repair? Is there a fee like a supplemental type certificate (STC)?

DW: For repairs, there is no fee like an STC. The technical data used in the repair and substantiation are the creator’s intellectual property. Each repair station has a different business model, but most profit from repairing the component and not selling intellectual property. Since operators are ultimately responsible for the maintenance and safety of their aircraft, they will need to review and approve the technical data that supports the repair. Most repair stations understand this and share the technical data with the operators to make money when the repair is carried out.

FLYING: Given the limited availability of OEM parts, how critical are engineered repairs to the industry?

DW: Repairs are becoming more critical than ever before. Supply chain issues have certainly increased the interest and demand for repaired parts. It has also become more common for OEMs to remove their repair data from CMMs, forcing the industry to develop their repair data. And in some cases, repairing a part can be more environmentally friendly than fabricating a new one.

MRO entities are dealing with rising material costs and shrinking supply chains in the aerospace aftermarket. Deploying a DER repair could be the difference between saving or scrapping the unit. Think of it as ultimate upcycling.

Richard is a US Navy Veteran, A&P Mechanic, and Embry-Riddle Aeronautical University alumni. His experience ranges from general and corporate aviation to helicopters, business jets, and commercial airliners. Former owner of a 145 repair station, he currently has an aerospace product management role and is a member of the T-C-Alliance. Follow him on X (Twitter) at @RScarCo.

Subscribe to Our Newsletter

Get the latest FLYING stories delivered directly to your inbox

Subscribe to our newsletter