Aviation Repairs: The Role of Designated Engineering Representatives (DERs)

 In Greensboro, North Carolina, I found myself at the Wall Street Deli, ready to indulge in a delicious Souvlaki platter when my phone interrupted the moment. Being in the aviation business, I understood the importance of answering it promptly. It was Josh Brien, my customer and the procurement manager at Genesis Aviation. He seemed distressed.

“Rick,” he said, “We have a problem.”

Early the next day, I was at his office door, where Brien presented me with several pieces of metal—an anti-skid brake part for a Boeing MD-11. Holding one of the parts confidently, I told 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 a massive governmental institution with around 48,000 employees, but even they need assistance in managing all the aviation responsibilities under their purview. This is where designated engineering representatives, or DERs, come in.

DERs are designees appointed by the FAA to ensure engineering data compliance with the appropriate airworthiness standards. They can work for a company or act as third-party contractors, and the FAA's engineering field office appoints them to specific technical disciplines in their respective geographic regions.

Why Use a DER Repair?

In the post-COVID-19 era, there has been an excess of used parts availability, with the used serviceable material (USM) market projected to reach $7.9 billion annually, according to Oliver Wyman, a management consulting firm. As the demand for USM grows by around 55 percent each year, it becomes a viable alternative to OEM solutions like parts manufacturer approval (PMA) parts and DER repairs.

How to Accomplish a DER Repair?

Back in 2018, when I received the call from Genesis Aviation's procurement manager, the anti-skid brake part (Meggitt part number 6000554 OEM) cost a staggering $15,329 each, with Aviall—now Boeing—as the exclusive distributor. The seven-month lead time quoted at that time was not acceptable for airlines in dire need of a part.

To address the issue, I contacted Fortner Engineering, where I spoke to Gary Fortner, the vice president of engineering. Recognizing the importance of viable spare parts, Fortner wrote a DER repair to reuse the housing and manufacture a new piston, thus saving numerous piston-sleeve assemblies from ending up in landfills and ensuring a steady supply of products for the airline.

DER Misconceptions

Let's clarify what a DER is. A DER is a person designated by the FAA to approve major repairs and major alterations on behalf of the agency, as confirmed by Debra Whittaker, engineering manager for Aerospace Coatings International.

Contrary to common belief, any non-OEM repair shouldn't be labeled as a DER repair. The correct interpretation is that a DER-approved repair refers to a major repair or alteration. Only major repairs require DER approval, while repair stations and operators can develop their minor repair data without DER involvement, as highlighted by Whittaker.

A Q&A with Debra Whittaker

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

DW: Repairs are typically developed out of necessity when the OEM's CMM (component maintenance manual) fails to address all possible maintenance activities or when parts become unavailable. Repairs may also be sought to reduce overall maintenance costs or enhance 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: There is no fee for repairs, unlike an STC. The technical data used in the repair and substantiation are considered the creator's intellectual property. Each repair station has its business model, with most profiting from repairing the component rather than selling intellectual property. Operators, being ultimately responsible for aircraft maintenance and safety, need to review and approve the technical data supporting the repair. Most repair stations understand this and share the technical data with operators when carrying out the repair.

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

DW: Engineered repairs are becoming increasingly critical. Supply chain challenges have heightened the demand for repaired parts, especially with OEMs removing repair data from CMMs, forcing the industry to develop its repair data. In some cases, repairing a part can be more environmentally friendly than manufacturing a new one.

In the aerospace aftermarket, MRO entities grapple with rising material costs and shrinking supply chains. Implementing a DER repair could be the difference between saving or scrapping a unit, making it the epitome of ultimate upcycling.

By leveraging DERs and their expertise, the aviation industry can navigate repair challenges, reduce costs, and ensure a steady supply of vital components, making aviation operations smoother and more sustainable