It must be, because everyone I know who flies a "big" warbird has either
an L of A for that type or certain types, & I have one friend who has an
old Unlimited L of A, whether or not it's grandfathered in he doesn't
know, as he hasn't had a use for it in maybe 20 years. Yes, an L of A is
used instead of a Type Rating for which no civil type is out there. The
L of A may be due to the performance of the a/c or even tho without
hanging bombs, etc., off a P-51 or Corsair you can't get it over 12,500
lbs. in the civilian world, the fact that their original design GW
exceeds 12,500, that requires an L of A. I do know a P-51D & Corsair
require a Letter, but a T-6 & T-28 don't. An A-26 requires a Letter, but
for a C-47, you get a DC-3 Type. I understand also that sometimes it
depends on the FAA Regional Office you're working with as how they
interpret their own Regs. No, I don't think it's quite legal to just hop
in & go in a P-51. A T-6, yeah.