The UK Government has announced it will acquire five Boeing 737-700-based E-7A Airborne Early Warning & Control (AEW&C) aircraft.

The announcement was made on March 22 by Defence Secretary Gavin Williamson, and will see the RAF’s five E-3D Sentry AWACS systems replaced by the E-7A in the “early 2020s” under a US$1.98bn (A$2,8bn) deal. The E-7A is known as the Wedgetail in RAAF service, and is also operated by South Korea and Turkey.

“The E-7 provides a technological edge in an increasingly complex battlespace, allowing our pilots to track and target adversaries more effectively than ever. This deal also strengthens our vital military partnership with Australia,” Secretary Williamson said. “We will operate the same state-of-the-art F-35 jets and world-class Type-26 warships, and this announcement will help us work even more closely together to tackle the global threats we face.”

Chief of the Air Staff, Air Chief Marshal Sir Stephen Hillier, added, “Today’s announcement about the procurement of five E-7 ‘Wedgetail’ Airborne Early Warning and Control aircraft is excellent news for both the RAF and wider Defence. This world-class capability, already proven with our Royal Australian Air Force partners, will significantly enhance our ability to deliver decisive airborne command and control and builds on the reputation of our E-3D Sentry Force.

“Along with Defence’s investment in other cutting-edge aircraft, E-7 will form a core element of the Next Generation Air Force, able to overcome both current and future complex threats.”

In order to free resources for a smooth transition to the E-7A, the RAF will retire one of its five operational E-3Ds immediately and consolidate its AEW&C operations. A sixth aircraft was retired several years ago and has been used as a spares hulk. An RAF rendering shows the E-7 flying over the Lincoln cathedral, which suggests the new aircraft will be based at nearby RAF Waddington, the RAF’s hub of Intelligence, Surveillance Target Acquisition and Reconnaissance (ISTAR) operations.

The Wedgetail agreement has been mooted since July 2018, and gathered pace after Australia’s announcement to acquire the BAE Systems Type 26-based Hunter class frigate prompted talks of closer defence ties and the possibility of a free trade agreement with the UK, especially with the UK’s exit from Europe looming.

RAF personnel reportedly visited the RAAF E-7A’s home base of Williamtown last August for a full brief on the aircraft and the results of its many missions in recent years over Iraq and Syria in support of operations against ISIS.

But just what role Australia will have in the UK’s program is yet to be announced. Four of the RAAF’s five Wedgetails were converted from ‘green’ 737s to E-7s at Boeing’s RAAF Amberley facility, and a large proportion of the company’s corporate knowledge of the system is now centred there and at Williamtown. The E-7’s primary sensor, the multi-mode electronically scanned array (MESA) radar is supplied by Northrop Grumman.

But like Australia, the UK is likely to want to perform the conversions in-country using local industry, a fact Mr Williamson articulated last November, and the work will most likely be conducted by Marshall Aerospace & Defence Group in Cambridge. But there may be export opportunities for Australian companies which have provided components, sustainment and training on the Wedgetail program.

Rather than switching to a newer 737MAX or a P-8-common 737-800/900 hybrid airframe, like the RAAF aircraft, the RAF’s E-7As will be based on the 737-700IGW which features heavier gauge landing gear from the -800, and three auxiliary fuel tanks. This will ensure commonality with the RAAF’s aircraft, and will remove the risk of having to conduct an expensive and time-consuming flight test campaign of a new AEW&C configuration.

The RAF will also need to decide how best to refuel its Wedgetails in the air to extend its mission endurance beyond eight hours. The RAF’s 14 A330 MRTT Voyager tankers use only hose and drogue systems, whereas the E-7A has been configured for boom refuelling through its Universal Aerial Refuelling Receptacle Slipway Installation (UARRSI) receptacle above and behind the cockpit.