History of Limited Type Certificates

[Lon Moer]

It’s worth noting that the P-51 Limited TC only covers the C, D and K, which is why most of the new-build high-back Merlin Mustangs are registered as P-51Cs (Bs have to be registered as Experimental)

Same reason the Cavaliers built for the civilian market recycled NAA/USAAF identities and the ones built for military contracts used new 67,68, and 72 serials.

And why the 67/68/72 aircraft that now fly on the US register use "heritage" NAA/USAAF identities that likely have nothing to do with where the metal came from.

Did you read that in a book?

[Noha307]

This lawsuit may have doomed the company, as in June of of that year a B-18 belonging to the Air Trading Corporation was noted as being sold at a sheriff's sale in Oklahoma City.

Hmm. Wonder which one it was? Checked Geoff Goodall's list and the only one listed with Oklahoma connections was 39-25/N62477, but Air Trading and Norman Blake (the buyer) don't show up in that history.

There's another possibility: a number of the old articles I come across have mistakes due to non-aviation inclined reporters misunderstanding important details. So it's possible that this was a case of a B-17 or something similar being misreported as a B-18.

Alternatively, according to another article, Norman Blake was president of a company called Southwest Aviation, Inc. So maybe the aircraft was registered under the company's name rather than his?

Finally, a different article notes that the company acted as a dealer for surplus aircraft. So a third possibility is that it remained on his books for such a short time before being resold that it was never really noted.

[Noha307]

• A North American test pilot, Paul J. Franklin, had his plane unsuccessfully stolen according to page 3, part 2 of the 13 October 1948 issue of the Los Angeles Times. This name matches the one on LTC-32. (For those wondering, based on a picture, the stolen plane was not a BT-14.)

A quick follow up on the BT-14 alluded to above: According to the North American T-6/Yale section of Warbirds Directory, the aircraft was s/n 40-1147 and it was struck off the USCR in 1971. Perhaps unsurprisingly, it is claimed to be the only actual BT-14 ever registered. However, it is interesting to note that two surviving flyable Yales have been converted to BT-14 configuration. (Although also representing a BT-14, the Yale at NMUSAF is not airworthy.) I thought maybe, in a weird twist, it was the existence of LTC-32 that made this possible. Yet, this does not appear to be the case, as the two aircraft, N314BT and N3361, are registered as NA-64s.

[rcaf_100]

However, it is interesting to note that two surviving flyable Yales have been converted to BT-14 configuration.

There would be a lot more work involved in converting a Yale to proper BT-14 configuration other than sticking an R-985 on the front. The outer wing panels were different (with the BT-14 having the later style with less leading edge sweep), as were the elevators, cowling, exhaust, instrument panels, etc. It would be akin to someone simply sticking a Merlin on an A-36 and calling it a P-51B. Close, but no cigar.

Yet, this does not appear to be the case, as the two aircraft, N314BT and N3361, are registered as NA-64s.

I believe you're referring to N55903 instead of N314BT. The latter still has an R-975 installed. N64FL in Arizona also has an R-985 installed.

[Noha307]

However, it is interesting to note that two surviving flyable Yales have been converted to BT-14 configuration.

There would be a lot more work involved in converting a Yale to proper BT-14 configuration other than sticking an R-985 on the front. The outer wing panels were different (with the BT-14 having the later style with less leading edge sweep), as were the elevators, cowling, exhaust, instrument panels, etc. It would be akin to someone simply sticking a Merlin on an A-36 and calling it a P-51B. Close, but no cigar.

Good point. The A-36/P-51B analogy is particularly well-taken. Would you say it would be easier to convert a T-6 into a BT-14 then? (I really need to pull out the Hagedorn T-6 book again.)

Yet, this does not appear to be the case, as the two aircraft, N314BT and N3361, are registered as NA-64s.

I believe you're referring to N55903 instead of N314BT. The latter still has an R-975 installed. N64FL in Arizona also has an R-985 installed.

Sorry, I should have clarified that I was basing those claims on the Warbirds Directory section, which refers to N314BT and N3361 as "BT-14 repl.". It doesn't say anything about N55903 or N64FL being converted. I don't know any more about any of those four airframes outside of what I read there, so you're probably right. Thanks for the correction and please feel free to shed some more light on the subject if you're so inclined.

[Noha307]

So, in doing some work on the Vintage Aviation Books and Periodicals thread I came across the Civil Aeronautics Manual defining airworthiness for limited category aircraft and, just like the definition in the FARs mentioned in a previous post, it is impressively short. The entire document, discounting the front matter, takes up less than a single page. Furthermore, according to the FAA's Dynamic Regulatory System, it was not amended or supplemented while in CAM form. (It was amended at least once, in 1965, after the series had ended.) The complete text is as follows:

Aircraft Airworthiness; Limited Category

 NOTE: This part is for the purpose of making available to the public certain military surplus aircraft which were originally designed for the military services of the United States for combat and other specialized purposes and which experience in military service has shown to be safe for operation so long as the operation is confined to flights in which neither passengers nor cargo are carried for hire.
 9.1 Aircraft category. Aircraft certificated in accordance with this part shall be classified in the limited category, suffix "L".
 9.2 Type certificate; requirements for issuance. A type certificate will be issued if the Administrator finds:
  (a) The aircraft is of a make and model which was originally designed and has been manufactured for, and accepted for use by, the military services of the United States for combat or other specialized purposes.
  (b) There is no civilian aircraft of essentially the same basic model for which an approved type certificate has been issued.
  (c) That information obtained from the record of operation of the make and model as a military aircraft does not disclose any characteristics which would render it unsafe when operated as a civil aircraft in accordance with the limitations and conditions prescribed by the Administrator.
  (d) Application was made for the type certificate prior to December 31, 1947.
 9.3 Airworthiness certificate.
  (a) Requirements for issuance. A limited airworthiness certificate shall be issued by the Administrator for an aircraft type certificated under the provisions of this part if he finds, after inspection, that the aircraft is in a good state of preservation and repair and is in a condition for safe operation. Such inspection shall include a flight check by the applicant.
  (b) Limitations. The Administrator shall prescribe in the aircraft operating record such limitations and conditions as are necessary for safe operation of the aircraft.

(Source: Aircraft Airworthiness; Limited Category, Civil Aeronautics Manual 9 (Federal Aviation Agency, 1959), 1.)