Key Point: There's ups and downs to the new aircraft.
While radars on fighters have been getting more and more powerful, dedicated airborne early warning and control (AEW&C) aircraft are still a necessity for most air forces to be competitive in aerial warfare. While the USAF continues to use upgraded versions of the E-3 Sentry, built on the airframe of the venerable Boeing 707, Russia is currently developing the A-100 AEW&C aircraft, which is built on the latest version of Ilyushin Il-76 military transport aircraft. However, the A-100 sports an active electronically-scanned array radar (AESA) in its rotating radome, in contrast to the E-3’s passive electronically-scanned array (PESA).
But does the new airframe provide the A-100 significant advantages of the American E-3 Sentry? How big of a deal is the AESA vs the PESA array?
Starting with the radar, the A-100 has some major theoretical advantages over the E-3 Sentry. While six revolutions per minute (RPM) has been the standard rotation rate for most AEW&C aircraft with rotating radomes (the earlier A-50, E-3 Sentry, and Japanese AEW&C all rotate at this rate), the A-100 cranks this up to twelve revolutions per minute. This allows for a faster “refresh rate” on tracking targets. Also, because the A-100 is an AESA, it has the capability to output multiple scanning beams to look for a target, while the E-3’s PESA is only limited to one.