The UK is in talks with Boeing to replace its fleet of ageing E-3 Sentry aircraft with E-7 Wedgetail aircraft.

The Financial Times reported here on Tuesday that the decision is expected to be confirmed ahead of a NATO conference this week.

The Chairman of the Defence Committee had earlier written to the Minister of Defence Procurement to request that any requirement for replacing the Sentry aircraft be put out to a competitive tender, rather than bought ‘off the shelf’ with no competition taking place.

AWACS aircraft perform an important function on operations, providing long-range early warning and surveillance capability alongside airborne battle management and communications relay functions. The Royal Air Force possesses six Boeing E-3D Sentry AWACS aircraft. They are currently due to stay in service until 2035, subject to a capability sustainment programme to extend their service life. Reports have emerged however that as part of the Modernising Defence Programme, the Ministry of Defence is considering cancelling the sustainment programme and replacing the Sentry fleet with a new aircraft.

In its letter the Committee criticises the Sentry fleet’s poor state of maintenance. The readiness and number of flying hours completed by aircraft have been reducing, and the Committee has heard anecdotal evidence that only one of the six E-3D aircraft is available for service at any one time.

On the possibility of Sentry being replaced with a new system, the letter notes the advantages of a competitive tender in terms of maximising value for money and allowing proper consideration of a range of alternatives. The Committee also considers that a competition is particularly appropriate in this case, as there are viable alternatives available which deserve to be given fair consideration.

Defence Committee Chairman Dr Julian Lewis MP said:

“AWACS is an important capability for the UK to maintain, particularly given the possibility of future conflict taking place in a heavily contested airspace against peer adversaries. The fact that the capacity of the RAF’s current AWACS fleet has been run down to such a low level is greatly to be regretted.

The Ministry of Defence, if it seeks to replace Sentry with an entirely new system, has the opportunity to regenerate this capability and to give proper consideration to the range of available alternatives through a competitive tender. The benefits of doing so are clear, and this is exactly the kind of engagement that the Department should be seeking with industry in its drive to modernise Defence.”


However despite this, the first three Royal Air Force personnel arrived in Australia last month for training on the RAAF’s E-7 Wedgetail aircraft.

According to the Australian Defence Magazine, three RAF crewmembers, comprising a pilot, an Electronic Support Measures Operator (ESMO), and a Surveillance and Control Officer began their Wedgetail conversion course with 2 Sqn at Williamtown about three weeks ago.

“Number 2 Squadron has just taken on-board some trainees, both from the UK and the US – both pilots and back end mission crew,” 2 Sqn Senior Engineer Officer (SENGO) Squadron Leader Shane Taylor said at RAAF Base Tindal last week. “They will be progressing through the training continuum over the coming twelve to eighteen months and certainly other countries are expressing an interest in this capability.” 

They say that the news follows the recent demonstration of the Wedgetail’s capability at RAF Waddington, home of the RAF’s Sentry fleet. One aircraft attended the Royal International Air Tattoo at RAF Fairford in July and deployed to Waddington after the show to demonstrate its capabilities to the UK’s Sentry force.

The E-7A Wedgetail provides one of the most advanced air battlespace management capabilities in the world and the Royal Air Force are rumoured to be interested in it to replace their E-3D Sentry aircraft. The aircraft is an Airborne Early Warning & Control aircraft with maritime search capabilities, it has the ability to control unmanned aircraft and it has intelligence gathering capabilities.

We recently reported that options for the future delivery of the UK’s Airborne Warning and Control capability are being explored, with the focus now on replacing the E-3D Sentry fleet.

We understand that upgrades however are reportedly considered to be expensive. According to Janes here, maintenance is becoming increasingly costly and replacing them instead might be the most cost-effective option.

Some industry commentators are also arguing for a new aircraft type altogether. The large sums of money allocated to upgrading the E-3D fleet should be used to purchase a more advanced off-the-shelf aircraft, a defence analyst has argued. Justin Bronk, Research Fellow, Airpower and Technology, outlines options for replacing the E-3 fleet in his paper ‘The Future of Air C2 and AEW: E-3 Sentry, Threat Technologies and Future Replacement Options’:

“The RAF’s E-3Ds need a £2-billion CSP both to bring them to rough parity with current US and French standards by the mid-2020s and to stretch the fleet out to 2035 in the process. However, the E-3, even in modernised form, is no longer a cutting-edge ABM&S system in a world where proliferating long-range missile systems and emerging non-Western low-observable fighters can force it to stay hundreds of kilometres from contested airspace, placing a higher premium on BLOS communications capacity rather than onboard sensors.

Even when it is able to operate closer to the battlespace, the AN/APY-1/2 mechanically scanned radar array common to all E-3s has significant inherent limitations in terms of its ability to detect low-observable, very slow moving and hypersonic threats, unlike more modern AESA-equipped AWACS types already in service with the US Navy and various air forces around the world. An AESA-equipped ABM&S platform with improved communications node capabilities, based on a commercial-derivative airframe, seems a logical alternative option which could provide the RAF with a more capable and efficient alternative to extending the life of the E-3D over the next 20 years.”

Both the Sentry and Wedgetail are designed to monitor airspace to provide threat detection of adversary aircraft and situational awareness on friendly assets.

The E-7A Wedgetail is based on a Boeing 737-700, with the addition of an advanced Multi-Role Electronically Scanned Array (MESA) radar and 10 mission crew console. They can cover four million square kilometres during a single 10 hour mission according to the Royal Australian Air Force.

“The E-7A Wedgetail represents an entirely new capability for the Australian Defence Force, providing an airborne early warning and control (AEW&C) platform that can gather information from a wide variety of sources, analyse it and distribute it to other air and surface assets. 

The E-7A Wedgetail can control the tactical battle space, providing direction for fighter aircraft, surface combatants and land based elements, as well as supporting aircraft such as tankers and intelligence platforms. Based on the 737-700 commercial airliner airframe, the E-7A Wedgetail features advanced multi role electronically scanned radar and 10 state-of-the-art mission crew consoles that are able to track airborne and maritime targets simultaneously.”

As the Second Line of Defense put it, the Wedgetail is designed with ‘the reach rather than range approach’; the MESA radar can be dialled up in terms of energy and focused in terms of direction on priority scan areas. As one Northrop Grumman engineer reportedly put it:

“There is a fundamental shift operationally in terms of how one uses the Wedgetail versus the AWACS. You no longer are limited or defined by a 360 degree rotator. You are able to configure how much power you want to put into your radar reach; it is configurable to the mission. The integrated IFF and radar functionality also allows the system to reach much greater than other systems into the battlespace to shape greater situational awareness in the battlespace. You can put the energy in the mission area where you have the highest priority.”

Image result for wedgetail top hat
The (aptly named for a potential British purchase) ‘Top Hat’ of the aircraft houses the radar.

The L-band electronically scanned AEW and surveillance radar is located on a dorsal fin on top of the fuselage, dubbed the “top hat”, and is designed for minimal aerodynamic effect.

The system provides 360 degree coverage and is capable of simultaneous air and sea search, fighter control and area search, with a maximum range of over 600km (look-up mode). When operating in look-down mode against fighter-sized target, the maximum range is in excess of 370 km according to Boeing. When used against maritime targets, the maximum range is over 240km for frigate-sized targets. MESA is capable of simultaneously tracking 180 targets and conducting 24 intercepts. Back in 2009, Boeing even demonstrated control of three ScanEagle unmanned aircraft from a Wedgetail.

In addition, the radar antenna array is also doubled as an ELINT (that’s a form of covert intelligence-gathering by electronic means) array, with a maximum range of over 850 km at 9,000 metre altitude.

Wedgetail looks to be maturing nicely in Australian hands with the major early teething troubles now ironed out. It’s also currently undergoing a major programme of further upgrades, due to be completed in 2022 that we reported on here.

Back in 2014, a Wedgetail conducted the first Australian sortie over Iraq supporting coalition forces conducting airstrikes against Islamic State. The next year, another performed the longest Australian command and control mission in a war zone during a 17-hour, 6-minute combat mission, requiring two air-to-air refuellings to stay aloft.

Photo by Bidgee [CC BY-SA 3.0], from Wikimedia Commons.
What we don’t know however is how closely the Wedgetail matches what the Royal Air Force want from an E-3D Sentry replacement but the degree of commonality with P-8A Posiedon Maritime Patrol Aircraft being purchased can’t be a bad thing, especially when Wedgetail also has an enhanced maritime search capability which may be useful in augmenting the relatively few P-8s being purchased.

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David Taylor

It seems to be the sensible option. It seems to be the only option. Just like Oz we need a plane with good range carrying sensors that can look a long way.

Just hope we buy enough of them. Enough for ‘home use’. And enough to support our efforts elsewhere.

Daniele Mandelli

So this could be another Carrot in the upcoming MDP.

Headline grabbing kit is always highlighted while the axe falls elsewhere.

Lee H

Hi Daniele MDP will deliver just that, it will be marketed as modernisation – something I have no problem with as long as those that win are the men and women in the military and the platforms they get given to generate military effect, the sharp edge of government policy. What we have now is the classic battle between the Treasury and the MoD. Treasury have a point, the MoD waster huge amounts of money with no accountability, cannot spend all their allocated money in year (an easy way to highlight this is manpower against requirement, you cannot pay who… Read more »

Daniele Mandelli

We shall see Lee. Revolution or same old. We shall see.

I’ve said before I could accept cuts IF there were suitable increases elsewhere.

But it never happens.

Otherwise. As always excellent comment and thank you.

Captain P Wash

If we spent millions upgrading the E3’s, we could then sell them to Brazil. Just Saying.


Brazil spent a lot of money on HMS Ocean which is a ship built down to commercial standards and is past its sell by date. So maybe they would buy a few old planes as well.


Brazil already has an AEW&C type in the form of the Embraer R-99A.


If the RAF goes ahead with the Wedgetail, it will be yet another RAF platform that was designed for boom refuelling. So is there also a budget to either enhance the Voyagers with boom refuelling capabilities, or pay for the R&D associated with adding a probe to the Wedgetails?


(Chris H) TwinTiger – The nose and front fuselage of a 737 is almost identical to the 707 (or rather ‘Dash – 8’) and our Sentry aircraft have drogue and probe refuelling. There is no technical or safety reason why Boeing could not build such a system into Poseidons or Wedgetail on the FAL. And if they can’t or won’t then I am sure Marshalls and Cobham here in the UK could do it. Its already been done so no ‘R & D’ is required. Just political will and telling Boeing who the customer is.


Thanks Chris,
You make it sound so simple! I’m glad that you believe that this will not be an issue. Sadly, the lack of a boom on the Voyagers is a major oversight for interoperability and future-proofing, IMO, that will be brought into sharp relief if the Wedgetails are indeed purchased.


… Just to add, I can’t recall reading that the RAF Poseidon fleet were also going to be fitted with probes? If not, surely refitting the Voyagers with a boom would be more cost effective that adding all those probes to RAF military versions of the 737s that were designed without them? Just saying …


Any idea how much the MOD saved by removing the probe? I agree it was a bit short sighted especially when it would have been useful for interoperability with the US. Maybe it was fitted for but not with a boom (to save maintenance costs) in which case it should not be difficult to upgrade the MRT fleet.


Chris the nose and front fuselage of the 737 is derived from the 707 but to say there is no technical or safety barriers to adding a probe to the former is absurdly naive and very ignorant of history. There is significant difference between these aircraft and I suggest you have a look at the ‘Haddon Cave’ report before making such simplistic assertions. Many decades separate the 707-320 that the E3D is built upon and the E-7 and P-8 variants of the 737. There is actually a fair amount of difference between the E-7 and P-8 making them in effect… Read more »

Lee H

Hi Not quite true on the Mk3 Chinook shambles but you are correct on the outcome – of which no accountability was atributed, the MoD got away with wasting £230m. Options were available to MoD from the outset on those aircraft, return to vendor, sell to UAE or field direct to Afghanistan – not of those options were taken up, it would have admitted culpability and someone would have to take the blame, that is not the way things are done. Always remember these aircraft were purchased against an SF requirement, if anyone knows how our SF work they like… Read more »


It was the Mod that stated they could homebrew the software on the MK. 3 Chinook so I am not clear how what I said is slightly untrue.

Nevertheless the outcome was costly and my core point is after that debacle there is no chance of refueling probes being bodged on without oem help.


(Chris H) fedaykin – and if you are referring to the software / access password cock up on Chinooks again I fail to see the relevance to a refuelling system that would be built in to an aircraft on a production line.

Not sure equating Cobham (whose business is supplying and fitting refuelling systems all over the world) to a lack of software knowledge by the MoD on Chinooks makes your point very well either.


(Chris H) Fedaykin – Why are you conflating a crash judged to be pilot error (rightly or wrongly) to a manufactured refuelling system? They are in no way similar! I agree the MoD / RAF made a pigs ear on maintenance on Chinooks and Nimrods and one knowledgable and experienced engineer was quoted as saying: “[reports] revealed a period of “neglect” during the 1990s culminating in lower staff levels and experience, inadequate training, over flying, failure to investigate faults, out-dated publications and poor communication” Utterly shameful but that failure to maintain aircraft has no bearing on a refuelling system fitted… Read more »

Lee H

Evening Thread didn’t go quite where I expected but WRT the probe. It would be easier to adapt the A330 or, through contract amend the support model to include a boom set, they are being built for other customers and the RAF could save face by stating that at the time of purchase it was not known what aircraft would be purchased to replace Nimrod and Sentry and on a balance of investment saving money for the taxpayer it was decided to go fro the lower risk option. Adding a boom also means updating the training and operation of the… Read more »


(Chris H) Lee H – the A330 MRTTs we have that are ‘KC.Mk 3′ aircraft have fuselage centreline drogue systems. This is the location for the ARBS (Airbus’ boom system) and as I understand it the airframes are passively engineered for ARBS fitment. Having said that I still argue it is simpler and less expensive (and operationally less restrictive) to have all our aircraft as ‘Drogue and Probe’. We only have 8 C-17 Globemasters, 3 RC-135 Rivet Joint not fitted with Probe refuelling. All are very long range anyway. So I am not sure the business case stacks up. And… Read more »


Well looking through your reply only affirms my general view that you haven’t a clue what you are talking about Chris along with your usual windbaggery! Firstly you have mixed up the Mull of Kintyre Chinook report with ‘Haddon Cave’ the report into the loss of Nimrod XV230. Further from that ‘Haddon Cave’ does not just focus on poor maintenance, it is a scathing review of the entire UK military Air worthiness system. A large proportion of the findings directly attack the activity of bodging in features and systems without proper OEM support and need I remind you a major… Read more »


(Chris H) fedaykin – Quote:
“Well looking through your reply only affirms my general view that you haven’t a clue what you are talking about Chris along with your usual windbaggery!”

So therefore I won’t waste your clearly valuable time any further and please forgive my temerity in trying to offer any opinions. I must learn that my position in this Forum is vastly inferior to superbly informed and experienced specialists like yourself.


What people seem to miss in boom versus drouge install for larger aircraft against fighters requirements is the fuel loads are considerable different. A large aircraft would certainly prefer the lesser hook up time derived from the flow rate delivered by the boom as apposed to the considerably slower rate from the drouge, which is quiet however suitable for fighters top up. It has to be remembered that the only reason probes were fitted to the likes of Nimrod, VC10, Belfast, C130 was that the drouge was the only delivery available via Victors and VC10 .


reminds me of a comment i made on an earlier article on Singapore’s acquisition…….. wtf were we the only county in the world to think not fitting the boom was a worthwhile cost saving…….. honestly it pisses me off that basically it boils down to accountants setting the requirements of what we end up with over what we actually need….. how short sighted is that looking now eh? and how much extra are we gonna end up paying to add the boom once we’ve realized our idiocy in the first place!

its bloody depressing!

Daniele Mandelli

Interesting that the Wedgetail has ELINT capability.

I’d read that 51 Sqns Nimrod R1s were particularly capable in ELINT as opposed to the SIGINT capability of the Rivet Joint that replaced them. The RAF was said to be losing a good standard capability in ELINT when the R1s were withdrawn.

Possible game changer there concerning replacement type chosen for the E3.

Daniele Mandelli

We really need an edit function. That should read Gold Standard.

John Clark

Second the edit function Daniele!
I have to agree, the Wedge Tail is really the only option for the RAF.

It’s a great asset and our Antipodean friends have already bankrolled the development, what’s not to like.


It has the same Elta ESM that was chosen for Nimrod MR4 – though without the spinning DF antenna.


Speaking to the guys of 2 Sqn RAAF at this year’s RIAT, they said the decision to buy Wedgetail is a done deal according to them. We definitely missed the ball on this one. We had an airframe with at least 30 years life that could have been converted to AEW in the Airbus A330 Voyager. Admittedly the aircraft is a lot bigger than a B737, but then it would have the capacity for future growth or multiple uses i.e. blending Sentry’s AEW with Sentinel’s battlefield surveillance. We have the designers and engineers who could have developed an AESA radar… Read more »

David Taylor

“The benefits that an airborne AEW platform bring to both offensive and defensive operations cannot be understated.”

Yes that is why we should have built the carriers around E2 and not the pointy fast bomb truck. I also fear that though Crowsnest will be good it might have been great if we had just spent a little more both on the system itself and the supporting hardware (brand new air frames for a start).

Daniele Mandelli

Will Crowsnest have the same over land capability that the Sea King ASCS radar had?


Yes, if not better. The Crowsnest is just an updated Thales Searchwater radar and Cerberus Mission System as fitted to the Sea Kings. I believe they’re having a new mechanical antenna array and new software for the mission system. So technically the range and resolution should be better than the previous system giving a much better picture over land.

Daniele Mandelli

Thanks Davey.

John Clark

I would agree Davey, having an asset that can be used for both AEW and Ground Radar surveillance and based on an A330 would the best possible solution, a real gold plated force multiplier!

However, the money simply isn’t there, so it has to be an off the shelf solution, that means wedgtail to me.

I dare say if we commit soon, the first aircraft could be landing at Waddington within a few years.

I would say 6 would be a sensable and affordable number.


Hate to burst your bubble but the DOD teied exactly that with a JSTAR & E-3 replacement and it never made it off the design stage. Having two powerful and different radars designed for different roles caused too much interference. You could have a radar that can do both roles but there would be compromises in its capabilities as it would have to be a secondary role.


The DOD tried that with a JSTAR & E-3 replacement combo and it didnt work. The idea of carrying 2 radars designed for different missions caused too much interference to make it out of the design stage.


No mention of numbers – like for like? Hopefully it’s not a case of give us your 6 Sentrys and we’ll give you 4 WedgeTails in return…. the usual dwindling number pattern that always seems to happen.

Sorry for being so pessimistic but this government gives us precious little to be optimistic about these days….

Daniele Mandelli

Australia have 6 I think.

South Koreans and Turkey 4.

6 should be the minimum to ensure 1 always deployed?


We also have a NATO commitment to fulfill

Lee H

Hi Daniele

5 is the absolute minimum
Aircraft 6 should be a 737-800 so flight hours can be maintained, don’t even need to buy the airframe, plenty of airliners in U.K. operate 737

Daniele Mandelli

Thanks Lee.

Fingers crossed for at least 5 then.


The 707 airframe is maxed out and has been for quite a while. It’s time to replace them with a modern variant that can be supported and shares commonality with other systems to save money. I have heard rumors that the USAF is seriously considering an unmanned platform as the AWACS replacement with a downlink to the Air Battle Managers similar to current drone operations that would involve a modulized system that could be set up anywhere – including on navy ships or even in the cargo holds of transport aircraft. The advantage here is to avoid exposing the crews… Read more »



If the MH6 Little Bird is being tendered as a proposal, the ADF is looking for a small gunship/operator insertion platform similar to what the U.S. Army’s SFOD 1 uses…

The folks in Oz have been very busy defense wise lately…


Daniele Mandelli

Apparently UKSF have always admired Little Bird.

Pity we can’t get any.

Daniele Mandelli

Especially as our own 657 Squadron AAC with Lynx was disbanded, removing the UKSFs deployable light helicopters.


Back in the Paleolithic period of Spec Ops (early 80’s) We would actually ride the rocket pod on the side of the Aircraft (straddling it and snaplinked inside because there was no room in the aft compartment of the gunships) ahead of the TF160 lift ships with the assault troops aboard – 1 would carry the FSO and I in that manner. Another would carry the (Ranger) company CO and his RTO. As soon as we hit Terra Firma (usually the highest point in the target area) we would disembark, the FSO would start controlling the gunships and fires, I… Read more »

Daniele Mandelli



One of the main reasons that the Aussies are looking at the “Little Birds” are that they are easily air-transportable by Herc/C17. You can get at least two in a stretched Herc with all the support equipment and engineers etc. It only takes an hour to get them flight worthy. I believe the Yanks had it down to less than 30 minutes after landing.
There has also been a development of converting the aircraft configured as a gunship to a remotely piloted vehicle.


It was my experience that 15 minutes was all it took to unload, set up the rotors, and go… There were two versions, the gunship, and a slick.


For Saint George

I had an idea if it was possible to order more P8 Poseidons, but have some configured with the systems from Wedgetail as well. Just an idea !

For Saint George

Maybe it would be possible to order more P8 Poseidon with the 737-800 air frame and have the kit from the Wedgetail integrated into it. This means a common air frame across the fleet and with the weapons fit could attack targets of opportunity. Just an idea.