Iran hostage crisis beginning in 1979. Also known as the 'Dry' missile. A version with simplified construction and no coolant conditioning. Did not enter series production. Developmental work started in January 1972. 7 X-AIM-54B missiles were created for testing, 6 of them by modifying pilot production IVE/PIP rounds. After two successful test firings, the 'Dry' missile effort was cancelled for being "not cost effective". The only improved model that was ever produced. It used digital electronics in the place of the analog electronics of the AIM-54A. This model had better abilities to shoot down low and high-altitude antiship missiles. This model took over from the AIM-54A beginning in 1986. /sealed round More capabilities in electronic counter-countermeasures. It did not require coolant during flight. The Missile was deployed from 1988 onwards. Because the AIM-54 ECCM/Sealed received no coolant, F-14s carrying this version of the missile could not exceed a specified airspeed. There were also test, evaluation, ground training, and captive air training versions of the missile; designated ATM-54, AEM-54, DATM-54A, and CATM-54. The flight versions had A and C versions. The DATM-54 was not made in a C version as there was no change in the ground handling characteristics. A 1970s proposal for a ship launched version of the Phoenix as an alternative/replacement for the Sea Sparrow point defense system. It would also have provided a medium-range SAM capability for smaller and/or non-Aegis equipped vessels (such as the CVV). The Sea Phoenix system would have included a modified shipborne version of the AN/AWG-9 radar. Hughes Aircraft touted the fact that 27 out of 29 major elements of the standard (airborne) AN/AWG-9 could be used in the shipborne version with little modification. Each system would have consisted of one AWG-9 radar, with associated controls and displays, and a fixed 12-cell launcher for the Phoenix missiles. In the case of an aircraft carrier, for example, at least three systems would have been fitted in order to give overlapping coverage throughout the full 360°. Both land and ship based tests of modified Phoenix (AIM-54A) missiles and a containerised AWG-9 (originally the 14th example off the AN/AWG-9 production line) were successfully carried out from 1974 onwards. AIM-54B A land based version for the USMC was also proposed. It has been suggested that the AIM-54B would have been used in operational Sea Phoenix systems, although that version had been cancelled by the second half of the