Il-86 Early Warning aircraft
Perceived Soviet requirements for an airframe better suited for the AWACS mission than CANDID, as well as for improvements in AWACS-related subsystems, led the US to project a Follow-on AWACS, possibly a modified IL-86 CAMBER, for the 1990s. Detection and tracking capability would be improved - perhaps out to 250 km against low-altitude, cruise-missile-size targets. Target handling and simultaneous intercepts will be increased. The system would have 360-degree coverage and longer time on station. DIA projected in 1981 that CAMBER will be adapted as a follow-on AWACS and reach IOC in 1991, ending CANDID AWACS production. With production of this Follow-on AWACS, about 100 AWACS aircraft would be operational by the late 1990s.
The Tu-114 was ideally suited on paper, but experience with the Tu-126 had just shown that radar interference from the huge counter-rotating props was prohibitive (which incidentally means the An-22 and Tu-95/142 are out too). The Tu-154M? Too short legged especially if saddled with bulky Soviet radar electronics. The Il-62M meanwhile was too small and starting to fade into obsolescence by then, same with the M-4 which wasn't even in production anymore. Apart from the Il-76 the only serious contender and certainly large enough to carry a powerful radar system. However its range was actually a bit shorter than that of the Il-76 (~3360km vs. 3800km at max payload, 8200km vs. 8700km ferry). With that major drawback in mind, its minor advantages in other respects could not outweigh the benefit of commonality with the Il-76 transport fleet.
It must have nevertheless been a pretty close-run thing between the two, a number of Il-86s were selected for the similar airborne command post role along with Il-76s (crew comfort for the higher-ranking occupants may have been the decisive point). The Il-96-400T (a bit of a non-optimum case, because for an AWACS version empty weight could be cut somewhat by using the shorter Il-96-300 fuselage, while keeping the 270t MTOW). It's obvious that the performance advantage is impressive to say the least - almost 13000km versus 8700km.
DIA projected the Soviets would use a new airframe for a Follow-on AWACS. The requirements for longer on-station loiter times and a larger cargo compartment for on-board processing equipment and crew rest area will probably drive the Soviets to a wide-bodied transport equipped with high-bypass-ratio turbofan engines. As suggested previously, the likely candidate is the IL-86/CAMBER. This aircraft became operational in 1981 and had low-fuselage-mounted wings for a potential increased radar look-down angle and a low-tail configuration, which permits 360degree coverage as compared to 320 degrees for CANDID. In addition, the large internal cargo area would allow for more AWACS-associated equipment (multiple sensors, data processing, etc.) on the aircraft as well as increased crew area.
A disadvantage of the CAMBER is its low-bypass-ratio turbofan engines, which were relatively heavy and registered high fuel consumption. A high-bypass ratio turbofan engine with improved thrust and 30- to 40-percent improvement in specific fuel consumption could be available for a CAMBER transport by 1986. Should this engine prove reliable and easy to maintain, DIA believed the Soviets would adapt the CAMBER as a follow-on AWACS by the early 1990s.
The upper bound on the 1981 DIA projection, some 150 AWACS, represents the estimated capacity of the Soviet electronics industry to produce reliable AWACS subsystems and avionics. CANDID and CAMBER transport aircraft were currently in production at rates which greatly exceed the projected AWACS fleet growth. Alternatively, Soviet inability to master AWACS avionics production on a moderate scale would force prolongation of the program. In this case, lower numbers may result.
Anticipation of US strategic standoff weapons, such as an anti-SUAWACS missile, would encourage Soviet development of a capability to detect and warn against such missiles when launched or airborne. Similarly, the Soviets could be expected to pursue the capability to decoy or defeat such US missiles with onboard equipment or tactics. The Soviets were expected to develop active and passive countermeasures as this threat emerges. For inertially guided threats, lethal defensive systems like air-to-air missiles may be suited to the AWACS. For seeker-controlled threats, decoys and jamming systems were expected by DIA.
An armed SUAWACS could be equipped with current technology systems, including an AI radar, air-to-air missiles, and an early-warning radar. The Modified FOXBAT look-down radar with an enlarged scanner would have better range resolution and target capacity than all current or estimated AI radars. A mix of AA-6 and AA-X-9 air-to-air missiles would yield a good capability against a spectrum of air threats. The early-warning radar system may be an adaptation of that being developed for CANDID, or it may be a new system in L-band, for example. DIA believed the Soviets would seriously consider this option by the mid-to-late 1980s and by the early 1990s would possibly build a few prototypes to investigate tactical applications and alternative force structures. It was unlikely that the Soviets would arm the AWACS in normal national air defense or theater operations. It was possible, however, that specific applications calling for extending radar coverage where fighter protection is unavailable would result in limited development of this concept.