T-59

Today I found a reference to the crash of a T-59, a civilian jet servicing with the USMC. (http://www.aero-news.net/index.cfm?do=main.textpost&id=4e4622bd-29f4-403e-a1ef-784fe7815cb6).

Digging further into this, a USMC press release at http://www.marines.mil/News/NewsDisplay/tabid/3258/Article/580490/update-civilian-aircraft-crash-one-marine-fatality-aboard-mcas-yuma.aspx revealed that this T-59 was a Bae Hawk flown by Air USA.

A further lead was at http://air-usa.com/aircraft, where it was revealed that Air USA operates, apart from the Hawk, also the Alpha Jet, the Mig-29 and the L29 Super Albatross. The Air USA website does not give designations.

Has anybody got any information on why the designation T-59 is used (the latest one I got is T-53) and who created this designation. Furthermore, what happened to T-54 etc. and have the Alpha Jet etc received similar T-something designations.

Digging further myself, I realize that model manufacturer Academy has a kit of a "T-59A Hawk", a Mk. 67 for Korea, showing up all over the web, such as here:
http://www.amazon.fr/Academy-12236-T-59A-Hawk-ROKAF/dp/B00CBGRILA

After looking up wikipedia, I find that the Republic of Korea Air Force introduced 20 T-59 (Hawk 67) in September 1992. Retired from service in 2013.

Perhaps the designation was reserved by the U.S. DoD in much the same way as T-50 was?

Thanks for pointing us into the right direction, ie South Korea.
A check of the FAA database shows that Air USA owns the following Hawk Mk.67's with construction numbers: 67-499, 67-503, 67-504, 67-505, 67-506, 67-508, 67-509, 67-510, 67-511, 67-512, 67-513 and 67-514. They have civilian registrations based on their construction numbers, followed by the letters XX eg N499XX.
A check with the Scramble.nl database confirms that these are ex South Korean Air Force, where there is a link to T-59. I assume T-59 is a South Korean designation but I am not familiar with that system (if indeed there is such a system). I did think for a moment that '59' could have been the BAe mark number, but that appears to be, as shown above, Mk.67.

As such, I would not consider T-59 as a US tri-service designation although I would guess that, if ever the T-series gets to T-58, T-59 will be skipped.