From Multi-Engine Turboprop Communiqué ME-TP-0012

From Multi-Engine Turboprop Communiqué ME-TP-0012

Date: March 2019

ATA 00 – Form 337 for Equipment or STCs Installed at the Factory

Technical Support receives requests for a Form 337 for equipment or STCs installed on King Airs at the factory. We have consulted with the Quality Department and they have provided the following explanation of why Form 337s are not issued.

Their explanation follows:

The FAA Guidance for issuing a FAA Form 337 exist under 14 CFR Part 43 Appendix B (14 CFR Section B43.1). However, the new aircraft manufactured under a Production Certificate is manufactured under Part 21. The newly manufactured aircraft do not enter into the (Part 43) Maintenance world or rules until it is issued a Standard C of A (FAA Form 8100-2).

FAA Order 8120.22 Rev A states the following in the applicability section:

3-1. Applicability.

  • Part 21, subpart G, applies to any of the following persons who desire to manufacture a complete product and article(s) with benefit of a PC:
    1. The holder/licensee of a § 21.21 TC.
    2. The U.S. holder/licensee of a § 21.29 TC, if the licensing agreement clearly provides for the TC holder’s and its Civil Aviation Authority’s (CAA) control over any design changes by the licensee. A working arrangement, associated with the respective bilateral agreement, must also be in place between the CAA and the FAA defining their respective responsibilities as State of Design and State of Manufacture.
    3. The holder of a supplemental type certificate (STC) when:
      1. The STC will be incorporated prior to the issuance of an original airworthiness certificate (OAC) to the aircraft; or
      2. The STC will be incorporated after the issuance of an OAC to the aircraft. In this case, the PC would authorize the manufacturing of associated STC articles in accordance with Part 21. However, installation of the STC and return to service of the product is accomplished under the provisions of 14 CFR part 43.

The further defines that there are three ways to incorporate an STC prior to issuance of OAC [two by means of Engineering (by merger/amending into the TC data or incorporation by reference in the TC Data) and one by incorporation under the PC which must be on our Production Limitation Record]. These are as follows and are all under Part 21 rules and not under Part 43 rules.

  • STC Modifications Incorporated by a TC/PC Holder.
    1. When the holder of the TC seeks and obtains its own STC, or is licensed to use another person’s STC data, the TC holder may amend the TC to incorporate the STC approval by reference. Another party’s STC that is incorporated during pro-duction and is referenced in and becomes a part of the TC need not be shown on the PLR. When a TC is amended to incorporate data approved under an STC, only the TC should continue to be shown on the PLR.
    2. When the PC holder of a TC obtains an STC, or related licensing agreement, but does not make the STC an integral part of the TC, the PC holder may incorporate the STC in production products prior to OAC approval, provided that —
      1. The PC holder makes application to the FAA to add the STC to its PLR,
      2. The quality system data are revised as nec-essary, and
      3. The engineering data submitted for the STC approval provide all the details necessary for manufacture and for making conformity determinations.
  • When a PC holder elects to use neither of the foregoing methods, the TC holder may incorporate an STC modification into production products only after OAC, in accordance with the provisions of part 43.

Only the last method after OAC requires the provision under Part 43.

Please note that at OAC we must list the STC incorporated at build that are installed by Method 2 (incorporation by reference in the TC Data) or 3 (addition to the PLR), we must list the STC on the application for airworthiness (FAA Form 8130-6), we must make a record in the aircraft logbooks, we must provide any applicable AFM/POH Supplements, and provide instructions for continued airworthiness.

Textron Aviation does not complete FAA Form 337 because we did not alter from aircraft at original build; but incorporated these STC at build. The FAA Record of these STC incorporated at build are listed in Block III of the original FAA Form 8130-6 which should be on file in the FAA’s AFS-750 database. If they cannot find a copy in AFS-750 Textron Aviation can provide one from our archive records.

If the aircraft is exported without issuance of a Standard C of A then the STC will be listed on the Export C of A (FAA Form 8130-4) and on the Application for Export C of A (FAA Form 8130-1). Copies of both are filed with the FAA at AFS-750 in OKC. Same rules apply about providing the required STC documents for logbook entries, Supplements and ICAs.

**Editor’s Note: We are aware of some discrepancies with the numbering and lettering, but the information is being published verbatim of what was on the Communiqué from Textron Aviation.

The above information may be abbreviated for space purposes. For the entire communication, go to

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