Block System?

Could someone explain to me the “Block System” in aircraft’s? I see various “Blocks” specifically on F-16 model kits.

Thanks in advance.

Similar to the variant system used like Spitfire MkIII or Mk VII; DC-9-30…it is a way to see what production series the aircraft is from. As modifications and upgrades are included into the production line or the aircraft are returned for refit/upgrade at either the factory or depot. They are fitted to the Block series designation. In some cases it is only a difference in the avionics or different powerplant. Some changes like with the F-16 are fairly drastic…the F-16As have little in common with the units now coming off the line. In fact the A’s are being retired and will start to be used as QF-16A in 2012.

“QF”?

Q is a drone designation from what I remember. Like the Aphrodite Project where they used BQ-7 or b-17s as radio guided missiles.

See here:

http://www.habu2.net/vipers/

http://www.reidairpublishing.com/RAP02.html