The Question: To field approve or to STC?

The Question: To field approve or to STC? By Joe Hertzler R ecently I was studying the field approvals of FAA Form 337s, what I consider to be the hottest issue between the FAA and industry, when it hit me - my Inspection Authorization may...

  • The field approval process as we once knew it is gone. We will never again see a field approval "for duplication."
  • The most effective way to obtain approved data is to hire an independent engineer with FAA designation (DER) to approve your data and submit the 337 with the supporting 8110-3.
  • Push back a little on the FSDO that will not recognize the signature of a DER and work through the differences. Let the FAA know that you can cover all of the disciplines yourself and then show them that you can.
  • Apply for and obtain an STC whenever you make modifications that will likely be duplicated on identical aircraft. This will mean breaking the modification down into pieces that can be evaluated and approved separately. The first one will take some time and money, but every installation after that will be a breeze in comparison.


Joe Hertzler is the president of AVTRAK Inc., an Aurora, CO-based company. Joe is an Airframe and Powerplant Mechanic with Inspection Authorization and also a Private Pilot.

We Recommend

  • Article

    Gone With the Wind: Field approval

    Gone With The Wind? The field approval process Stephen P. Prentice The process has essentially remained the same . . . some areas required more attention to detail than others and that...

  • Article

    The Field Approval

    I have been told that getting an FAA field approval is a lot like getting an elephant pregnant.

  • Article
    The Complexity of PMA and STC Approvals

    The Complexity of PMA and STC Approvals

  • Article

    Cargo conversion

    Cargo Conversion By Jeremy R.C. Cox May-June 1998 In the United States alone, over 360 billion dollars worth of goods are shipped via airfreight every year. This figure is going to...