Most pilots don't know what FAA DERs are (Designated Engineering Representatives) but they play a very important role in aviation, even for General Aviation. During my career in aviation I owned an aviation insurance agency through which I insured aircraft for individuals, corporations and fixed base operators. One of my insureds owned a number of Piper Navajo aircraft, and during one charter flight the pilot made a very poor decision. 10/19/1988 Piper PA-31-350 Accident I received a telephone call from my insured informing me that during a circle to land approach in fog at the Big Rapids, MI airport his pilot had bent the wing on N300HF when it struck the runway during the landing. Damage to the aircraft was substantial, and the left wing on the aircraft was bent and unrepairable. You can read the details of this accident in the Official FAA Accident Report on PIPER PA-31-350 Accident in BIG RAPIDS, MICHIGAN, USA on 10/19/1988. Needless to say the owner was very concerned that the airplane would be a total loss. The only viable repair solution was to get another left wing to replace the damaged one; however, we were unable to locate an undamaged Piper Navajo wing but were able to locate a Piper Chieftan wing. Navajo Wings Are Not Chieftan Wings! The problem was the wing we located had some differences from the damaged wing on N300HF. This is where I first became aware of FAA DERs and what they were capable of doing. It was not possible to just stick a Piper Chieftan wing on a Piper Navajo, and vice versa. We had to find another solution to fix this aircraft. Enter The FAA DERs It turned out that FAA DERs with the proper certification can approve modifications to the structural parts of an aircraft. In our case the FAA DER was able to certify the Chieftan wing (with some modifications) to allow us to install it on the Navajo aircraft. Problem Solved! FAA DERs Designated Engineering Representative (DER) FAA DERs are individuals, appointed in accordance with 14 CFR § 183.29, who hold an engineering degree or equivalent, possesses technical knowledge and experience, and meet the qualification requirements of Order 8100.8D. FAA DERs may be appointed to act as a Company DER and/or Consultant DER. Company DERs can act as DER for their employer and may only approve, or recommend approval, of technical data to the FAA for the company; Consultant DERs are individuals appointed to act as an independent (self-employed) DER to approve or recommend approval of technical data to the FAA. DER Technical Disciplines Acoustical Engineering Engine Engineering Flight Analyst Flight Test Pilot Powerplant Engineering Propeller Engineering Radio Engineering Structural Engineering System and Equipment Engineering If you ever find yourself in need of an FAA Consultant you can check the FAA Consultant DER Directory which provides a list of Consultant DERs, by state and technical discipline. Be sure to fly safe, avoid accidents and you will never need any FAA DERs to assist you! In the meantime keep your wings straight and level Hersch! Please share "FAA DERs" with your friends using the buttons below. Thanks! Until next time keep your wings straight and level Hersch! JetAviator7+ ps: Don't forget to sign up for updates via email for "All Things Aviation" here!