See what happens when you don't read one of these threads - you miss the best stuff!
Interesting topic this. I used to maintain a very old F-28, and hated the thing - but I think it was much more to do with the particular aircraft, and perhaps even more to do with the particular owner!
I still never really thought of them as real machines, until I had the great pleasure of witnessing Dennis Kenyon flying one! Dennis is able to demonstrate the capabilities of the aircraft in such an amazing manner, that I have never known anyone to not be impressed by an Enstrom after that!
All of the Enstrom owners I have ever met, have had nothing but good to say about them - so just shows you what I know (knew?).
In response to the certification issues, I have addressed some of this in the Swazi thread.
For FAA standard category certification, a product is eligible for certification under a Type Certificate if it conforms to that TC. It is also possible for a product that was not manufactured under a TC to be certified in Standard Category, if it can conform to the TC (unusual situation, but possible).
In the instance of a former military aircraft. FAA Restricted Category certification is limited to aircraft previously operated by the US military
ONLY, any foreign military operation removes eligibility (of course you need to have a TC as well). It used to be possible to cobble a Restricted TC together very simply and reasonably rapidly, but those days are gone now.
FAA Standard Category certification is available for ex-military machines, regardless of who or where they were operated so long as they conform to a TC. The key to certification is the ability to conform the product to the TC, and good paperwork which also includes repairs, overhauls etc; - standard fare for the business. This option also exists for many agencies outside the US, as a complete standard airworthiness and certification package exists for the product and the issuance of the TC.
The caveat to this statement, is to ensure that the Serial Number of each aircraft is included in the TC. It is not unusual to see specific S/No: aircraft noted as ineligible on a TC, generally as a result of a configuration or build change that was never commercially certified, typically for military customers, often overseas!
That military operators purchase straight commercial products make good sense for the military and the Operator, as the products retain some useful value at the end of their military life and are generally quite marketable.
Current ex-military aircraft from a variety of sources that are in standard category commercial operation include (not a definitive list), Bell 47, 205, 206, 212, 214B, 214ST, S64E, S64F, MD500D, etc....
Obviously it is important to do the background work before starting, as many people have bought aircraft that are ineligible for certification for one reason or another (saw this very recently!). This includes ex US military aircraft that may be ineligible for certification to a Restricted Category TC, due to the advanced modification state of the current aircraft, compared to the original aircraft used for certification (just been through this issue at great length).
I was recently formally advised by the FAA that some of my Restricted ships did not conform to the TC and would have their Airworthiness Certificates withdrawn in 30 days. The basis for this action was the FAA being advised that the aircraft was not manufactured under the data plate the manufacturer had installed at manufacture, but under the BUNO (mil ID) that is used to track it in the military inventory. We were able to resolve the issue pretty simply, not least by referring to the manufacturers own drawing - but makes you sweat a little when you are first told that on the phone!!!!
I also have had access to the entire UH-1 series engineering reports and life limit package, which makes for some pretty interesting reading with respect to the commercial models!
There are many pitfalls for the unwary - so go in with your eyes open,
ask questions and track down the people who know what they are talking about for the specific model.