This is coolbert:
From an acknowledged aviation authority some comments, the dual use military aircraft NOT such a great idea as I might have thought it was. Those trainers/combat warplanes such as the Yak-130, South Korean Golden Eagle or the Italian M-346 the capability of which is more limited that what I had might imagined:
"Trainers are usually lighter aircraft, designed basically to carry pilot and instructor, and sometimes a tiny bomb load (practice bombs, weighing 25lbs each, having the ballistic characteristics of the 500-3,000lb bombs they are supposed to emulate). As you can see, not much carrying capability. Nor any room to expand to carry more and better avionics to help navigate, guide weapons to their targets, find and track enemy planes, warning devices, heavier systems to resist gunfire, redundant systems to compensate for when the gunfire is not resisted, heavier landing gear to handle the bigger loads, and on and on....."
That dual use warplane [trainer/combat] can be effective during a counter-insurgency operation [COIN] but also ONLY in a limited way and given the nature of modern warfare also susceptible in a manner that a full-size combat aircraft is not!
"The best use of small trainers as combat aircraft comes when you are fighting guerrilla wars with no sophisticated anti-air capability. Even a shoulder-fired missile (MANPAD) is deadly to those smaller aircraft, which almost always fly at much slower speeds--a T-37 is dog meat for the MANPADs, while a F-4 at a normal speed at low altitude can rarely be touched by one."
MANPAD such as the elderly but still effective Soviet era SA-7! that American T-37 in Vietnam called the A-37 when equipped with 7.62 mini-guns.
"If you add the protective electronic equipment, nav systems, guidance capabilities, etc. to the trainers, they too will develop more down time for maintenance."
So I am incorrect but I might judge not entirely so! I stand corrected and am more the better for it.