Since the Black Hawk will eventually be replaced with the V-280 Tiltrotor by the Army this reminds me of the old Huey joke. “When the last Black Hawk goes to the boneyard, the crew will ride back on a Huey.” Who knows, eh? Heard that years ago when I was an A&P at PHI in Lafayette, Louisiana.
Based on the lessons learned from the current war in Ukraine, the Army and Marines might want to rethink their use of helicopters in combat. The Russian helicopter fleet has been taking a real beating from shoulder-launched antiaircraft missiles.
Maybe switch to the Greek alphabet?
I don’t know of a case where they used the whole alphabet on an aircraft itself, but it does happen with components and upgrades to them. After “Z” comes “AA” then “AB” then “AC”. I remember one device that went as far as “BC” because they counted every new software load as a new component modification.