
Pilots flying the early Block 1 F-16As complained that the black radome stuck out like a sore thumb during simulated air-to-air combat and made it easy for the enemy to visually acquire the F-16. On Block 5, the gray radome was introduced, which became standard for all later Fighting Falcons. There were 99 F-16As and 27 F-16Bs built to Block 5 standards, which were ordered in Fiscal year 1978-79. Surviving Block 5 F-16A/Bs were brought up to Block 10 standards in 1982-84.
Block 5 F-16A/Bs destined for Israel have minor (but unspecified) modifications
which are unique to Israel. Long after entering service, they may have
had improvements which include the installation of Loral Rapport III electronic
countermeasures equipment and new chaff/flare dispensers, possibly�
AN/ALE-40s. Some Israeli aircraft may have the Elta 2021B radar in place
of the APG-66.
Block 10 consisted of 169 aircraft (145 F-16As and 24 F-16Bs), ordered
in fiscal year 1979-80. Block 10 aircraft incorporated some minor internal
changes. Beginning with the Block 10 series, the USAF introduced a letter
suffix within each block, with the letter initially signifying little more
than the order in which batches of aircraft were produced. This letter
suffix took on greater significance in later Blocks. Most surviving Block
1 and 5 F-16s were later upgraded to Block 10 standards, which included
the graying of the radomes. Aircraft belong to the original four NATO users
were also brought up to the Block 10 standard. These aircraft are, however,
deemed unsuitable for future upgrading.