CAVU Café: Royboy’s Prose & Cons

*Note: The views expressed in CAVU Café: Royboy’s Prose & Cons blog are those solely of the writer and are not necessarily shared by the Aviation Suppliers Association or the Association’s staff, members, or Board of Directors.

   About Roy Resto


Your customer has an urgent need for hard to find new Hi-Lok fasteners. You finally locate some New Surplus parts, but your source shares that the trace is to government military stock. Your customer’s Jurassic policy is that they will not accept any parts with trace to a government/military source period, so their aircraft languishes for lack of parts, and they will pay a lot more waiting for the commercial sources to get stock. Is this policy in the best interest of their fleet and budget?

We’ve all seen the wording on certifications which state variations of the following:

“The undersigned certifies that the part(s) listed above were not obtained from a US Government or Military Source…”

“The part(s) was/were not previously installed in a public aircraft, such as a government or military use aircraft…”

What, do these parts have leprosy? And therein lays the basis for this discussion.

Existing guidelines need to move beyond the black and white blinders in effect for this type of trace. Most importantly, keep in mind that there is not one regulation that prohibits the use of parts traced to government or military sources. So, when should we be concerned, and when does this not matter?


  • Hardware including standard parts (assumed to be New or New Surplus). If the part number you need for your commercial application is the exact part number traced to a government/military source, take them! Those bolts, light bulbs, rivets, nuts, and connectors don’t care whether they are installed on government or civilian applications (pardon the anthropomorphic application).
  • New Rotables or LRUs (Line Replaceable Units) made to FAA standards. During my military career I often remember seeing data plates on units clearly marked in accordance with FAR 45 for TSO and PMA identification, meaning they’re FAA approved. These classically are called Dual Use parts; that is, they can be interchangeable between civilian and military applications. For example, those wheels and tires on the President’s Air Force One are made to TSOs and are the same parts and part numbers flown on civilian 747s. By the way, expect to see a rise of such parts in the coming years since the government is shifting to increased use of COTS, Commercial Off The Shelf. The reason for this makes economic sense; if a military aircraft design needs a Satcom (Satellite Communications) radio, why not use one already in use on the civilian aerospace market? This saves considerable developmental costs.


  • Rotables or LRUs which have undergone maintenance (overhauled, repaired, inspected, etc.), and which are Dual Use parts. The maintenance manual used to overhaul and repair these parts most often is called, depending on which branch of service is doing the maintenance, for example, TOs (Technical Orders), NAVAIR, or DMWR (Depot Maintenance Work Requirements). These may or may not differ from their civilian counterpart CMMs (Component Maintenance Manuals). Also, what in the civilian world are commonly called Service Bulletins and Airworthiness Directives find their military equivalents for example, in TCTO (Time Compliance Technical Orders) or Airframe Changes. You’ll know instantly these documents have been used because the accompanying paperwork states it was ‘Overhauled in accordance with TO…’ The use of these military maintenance manuals constitutes perhaps the best logic on the existing prohibitions on using military/government parts on civilian applications. But does this mean there are no options?
    • o Royboy’s advice. Let’s say your customer is in dire need of that dual use Satcom terminal. You locate one and it clearly states it’s been repaired in accordance with a TO. Have the part sent to a repair station/AMO, explain that it was obtained from a military/government source, and that you want the part inspected and processed in accordance with the applicable civilian CMM. You’ll likely get an 8130-3 with the CMM citation and voila, you’re good to go. It’s interesting that for many dual use parts, the TO is a one-page cover sheet directing you to process it in accordance with the attached CMM. A good example of this is the military’s CFM56 engines it designates as the F108. If you saw the F108 TO, you’d see that it is identical to the CFM manual.
    • I recall many years ago when a person who was defending their military/government trace policy, expressed that military parts may have been subjected to unusual operational maneuvers not experienced in civilian flight such as high-g and inverted maneuvers. First, it’s unlikely that such parts are dual use, but if they are, once again, send the part to a repair station/AMO explaining the concerns and have a hidden damage inspection done along with the overhaul or repair to the civilian CMM.

    An interesting sidebar twist (before anyone wags their finger at me) is the C-130. Its civilian version is the L-100 series aircraft. For the L-100, there is a document which states that in most cases the maintenance manuals to be used for this civilian model are TOs, not CMMs.

    By the way, the most conspicuous indication that a part may be dual use is that it is exactly the same part number.

    This is an example of a Dual Use Part which in this case is used on a C-130H when I took the picture. Note the TSO number marking per FAR 45:

    There was a time…

    • There was a time when Non-Incident Statements dominated, and nobody would touch a part removed from a stated incident or accident aircraft. For more information see my article at this link:

    Today we see a shift to the more enlightened Incident Clearance Statement (ICS) whereby, and I paraphrase, that even if the part had been removed from an incident or accident aircraft, its airworthiness has since been established.

    • There was a time when domestic airlines would not accept trace to foreign airlines…
    • There was a time when airlines would rarely accept surplus parts…
    • There was a time when airlines would not accept PMA substitute parts…

    The obvious inference is that industry evolves from rigid paradigms when common sense prevails. Maybe it’s time for this same common sense to be applied to parts traced to government or military trace.

    Over ‘n out

    Roy ‘Royboy’ Resto

    Posted By Mat Meyer | 8/1/2023 12:49:55 PM

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