Hoi there mates, it seems to me... that not all of the RBAF vipers have the IFF. Been looking around and it's hard to tell... as far as I know #111 (first viper delivered) and #101 do not have the IFF antennaes. The rest does.
Has anyone has seen any other viper w/o IFF.
 Bahraini F-16C Block 40 #111, armed with 4 AIM-9 Sidewinder missiles, on a desert airfield. This aircraft was the first F-16 delivered to the RBAF
 Bahraini F-16C Block 40 #101, armed with 4 AIM-9 Sidewinder missiles, on a desert airfield. This aircraft was the first F-16 delivered to the RBAF
Cheers.
Jochem |