Field Approvals (FAA Form 337) on Aircraft Being Exported

by Jerry Mullins
(Menominee Michigan US)

Do field approved (FAA Form 337) installations have to be listed on the Export Certificate of Airworthiness Form 8130-4 when exported to Japan?

COMMENTS: I will start by describing what a field approval is for those who don’t know. Field approvals were widely used in general aviation for minor alterations to an aircraft when there was no FAA approved data available to perform that alteration. These approvals are documented in block 3 on a FAA Form 337 and are similar to a one-off Supplemental Type Certificate (STC). Only the FAA can perform field approvals.

These types of approvals are not as commonly used today, except for some ferry tank installations. Now a person altering an aircraft is referred to a Designated Engineering Representative (DER) who can review and approve the data used to perform the alteration on a FAA Form 8110-3. With that data, a properly certificated person can perform the alteration and document the approval on the FAA Form 337.

The special import requirements (listed in AC 21-2J Appendix 2) vary between countries. Japan requires that the aircraft conform to a JCAB approved type design. They require exceptions to be listed on the FAA Form 8130-4 if the aircraft does not conform to the JCAB type design.

STC’s, Form 337 field approvals, and FAA Form 8110-3 approved alterations would not meet the Japan authorities import requirements unless there are the same STC’s, field approvals, or other alterations already approved and being used in Japan.

However, the JCAB also indicates that “After the issuance of a U.S. Export Certificate of Airworthiness, only the modification for ferry flights covered by FAA Form 337 is acceptable.

Ferry tank installations are often approved by a field approval on a FAA Form 337 for the purpose of overweight over water ferry flights.


No, the FAA Form 337 field approval would not be required to be listed as an exception if it is being issued for the purpose of ferrying the aircraft to Japan, where the installation will be removed upon arrival.

Yes, if the FAA Form 337 field approvals (other than those required for the ferry flight) and any other alterations have not been previously approved by the JCAB.

Prior to listing those exceptions and issuing the export certificate of airworthiness FAA Form 8130-4, there would have to be correspondence between the FAA and the Japan authority and written confirmation provided by the Japan authority that they will validate the FAA Form 8130-4 with those exceptions listed.

Those items listed would then have to be approved by the Japan authority prior to the issuance of a Japan airworthiness certificate.

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