The FAA's Designated Engineering Representative (DER) program lets qualified individuals approve technical data on the FAA's behalf. For aircraft modifiers, MROs, and operators, retaining an experienced DER is the difference between an approval that ships and a project that stalls in coordination.

LB Aircraft Engineering employs FAA DERs, DARs, and DMIRs as part of our permanent staff — not subcontracted. That means tightly integrated certification work, predictable schedules, and a single point of accountability from the first drawing through Form 8110-3 issuance.

DER Disciplines on Staff

  • Systems and Equipment DER — avionics, communications, navigation, surveillance, instruments, autopilot, environmental, fuel, hydraulics
  • Electrical Systems DER — aircraft electrical power, distribution, EWIS, lightning/HIRF protection, EMI/EMC compliance
  • Structures DER support — via established consulting partnerships for primary and secondary structure, repairs, and damage tolerance
  • FAA DAR (Airworthiness) — conformity, Special Flight Permits, Export Certificates of Airworthiness
  • FAA DMIR — manufacturing inspection and 8130-3 issuance for PMA parts

Approved Data & FAA Form 8110-3

Our DERs prepare and approve the technical data the FAA accepts as showing compliance with applicable airworthiness regulations. Typical deliverables include:

  • FAA Form 8110-3 Statements of Compliance
  • Engineering analyses, test plans, and test reports
  • Structural substantiation, electrical load analysis, EMI/EMC reports
  • Software / complex hardware compliance to DO-178C and DO-254
  • System Safety Assessments (ARP4761), Functional Hazard Assessments
  • Master Minimum Equipment List (MMEL) revisions
  • Aircraft Flight Manual Supplements (AFMS)
  • Repair data approvals, alteration data, Major Repair / Alteration Form 337 substantiation

Engagement Models

We support DER work in three common engagement structures:

Project DER — full STC / TC project lifecycle
Consulting DER — specific MoC findings & data approvals
DER-on-call — recurring AOG / repair / alteration support

Industries & Applications We Support

  • Air carriers (Part 121) and on-demand operators (Part 135)
  • FAA Part 145 repair stations needing approved repair/alteration data
  • OEMs and Tier-1 suppliers preparing certification data packages
  • Defense contractors with civil derivative aircraft (FAA-aligned military programs)
  • VIP/head-of-state and corporate flight departments
  • Special-mission operators (ISR, surveillance, medevac)

Frequently Asked Questions

What is the difference between a DER and a DAR?

A DER (Designated Engineering Representative) approves technical engineering data — essentially saying the design and substantiation comply with the FARs. A DAR (Designated Airworthiness Representative) issues airworthiness documents like Special Flight Permits and Export C of As, and performs conformity inspection. We have both in-house.

Can your DER approve repairs and alterations on my aircraft?

Yes — if the data falls within their delegated authorization. Our Systems & Equipment and Electrical Systems DERs regularly support major alteration data, repair approvals, and Form 337 substantiation for Part 121, 135, and corporate operators.

Do you provide DER consulting on EASA validations?

Our DERs prepare data with EASA validation in mind. While DERs are an FAA construct, the engineering compliance work translates cleanly into the EASA Part 21J framework, which speeds foreign authority validation.

Need a DER on Your Project?

Tell us your aircraft, the modification, and your schedule. We'll match the right DER discipline and propose an engagement model.

Request a Consultation +1 (305) 704-8734