Boeing has installed a Multi-role Electronically Scanned Array antenna on a second 737-700 for Australia 's Project Wedgetail, an airborne early warning and control program. The Northrop Grumman-built MESA antenna, at 35.5 feet long and weighing more than three tons, is the critical sensor aboard the aircraft. It's designed to provide optimal performance in range, tracking, and accuracy. While modifications on the second Wedgetail 737continue, the first Wedgetail aircraft is undergoing an airworthiness flight test program. Australia has ordered six 737 AEW&C aircraft.