Primarily reserved for refuelling missions, multirole tanker aircraft are also used to transport cargo and personnel, support humanitarian efforts, or in times of crisis such as the COVID-19 pandemic carry medical supplies.
Such is the current demand for tankers that NATO has admitted it needs to address a shortfall in air-to-air refuelling capacity across Europe. While, the US is tackling the technical troubles that have long plagued Boeing’s KC-46A Pegasus and could next opt to buy around 140-160 LMXT aircraft based on the A330, on offer jointly from Airbus and Lockheed Martin under the KC-Y/Bridge Tanker programme.
Up to November 2021, the DoD had a firm strategy in place to manage tanker aircraft by replacing a fleet of 396 KC-135s and 59 KC-10 Extenders and committing to a three-step process, beginning with the acquisition of 179 KC-46s to replace roughly a third of the KC-135 fleet, according to a Congressional Research Service report.
It notes that the second phase was due to see a second solicitation cover an additional 179 tankers under KC-Y and be stood up as a new competition for industry, as opposed to a follow-on contract for Boeing and the KC-46.
The final phase had been expected to see a new acquisition, labelled KC-Z, as a KC-10 replacement, but this was ‘dropped’ by the USAF in favour of another KC-46 buy, added the report. Thus far, however, the air force has only defined KC-Z as an ‘advanced’ air refuelling tanker.
‘Given many years of delays, some due to problems with the KC-46 and some due to recapitalisation funding, the air force doesn’t want to jeopardise the schedule to replace its very old fleet of KC-135s and KC-10s,’ Richard Aboulafia, MD of AeroDynamic Advisory told Shephard.
‘I think they are only going to feel comfortable when they have a roadmap to about 300 KC-46s and by [potentially] opting for some kind of alternative tanker [under KC-Y] that allows for competition on price and performance improvements, but it would jeopardise the recapitalisation roadmap.’
There is no guarantee KC-Y will lead to a new tanker being acquired. Doubt currently hangs over a competition being formally rolled out after Air Force Secretary Frank Kendall told the House Armed Services Committee in April 2022 that lack of demand for a new aircraft could lead to KC-Y being cancelled, adding that a final decision had still to be taken, according to Breaking Defense.
Bang for the buck
‘I look at [Kendall’s] statements as saying USAF need to do [further] work to make sure that as they recapitalise the tanker fleet, they’re getting the best bang for their buck,’ said Ken Moss, LMXT capture manager at Lockheed Martin told Shephard. ‘When we are putting together our proposals and communicating with the programme office that’s what we have to prove. That’s what we’re doing.’
He also confirmed that the USAF has published documentation outlining a plan to issue a KC-Y acquisition strategy in Q1 2023.
‘There are some milestones they’ve got to meet before then but we expect, in the next four to five months, to see some indication about what they want to do and based on our assessment of when they would need to execute this [next phase of] continuous capitalisation at the end of 2024 or start of 2025. That means it [KC-Y funding] needs to be in the FY2024 budget, which starts at the end of this year,’ added Moss.
‘At this time, the KC-Y programme office does not have final requirement documents nor are requirement documents available for public release,’ the office stated in a 13 July 2022 notice to industry. ‘Requirement documents that may be in draft form at this time have the potential to change going forward.’
In order to keep Boeing ‘performing’ well on the KC-46 programme, the USAF should continue to maintain the ‘prospect of competition’ with KC-Y, according to Todd Harrison, senior associate of Aerospace Security Project and Defense Budget Analysis at CSIS.
‘I would keep revisiting that decision [whether to pursue a KC-Y acquisition or not] every year and not lock myself into a long-term production contract with one manufacturer or another.’
The LMXT offer is based on the proven Airbus A330MRTT but would offer greater fuel capacity, be fitted with a number of US-specific systems and allow for autonomous boom operations.
Considering the disruption that crewed boom refuelling activities have caused Boeing and the KC-46, alongside the fear of mistakes causing fighter jet surfaces to be scratched, an autonomous approach should have obvious operational advantages.
‘Autonomy is a capability that we ought to be exploiting to our maximum advantage when we look at the next long-range US Air Force tanking asset,’ said Lt Gen (ret) David Deptula, dean of the Mitchell Institute for Aerospace Studies.
In partnership with the Republic of Singapore Air Force, Airbus received certification for the A330 to conduct daytime automatic air-to-air refuelling (A3R) boom operations in July.
‘The A3R system requires no additional equipment on the receiver aircraft and is intended to reduce air refuelling operator workload, improve safety and optimise the rate of air-to-air refuelling transfer in operational conditions to enable air superiority,’ the manufacturer noted in a statement at the time.
It also said that a demonstrator dubbed Auto’Mate, designed to ‘develop, adapt, mature, integrate and evaluate technologies enabling Autonomous Assets Air-to-Air Refuelling and Autonomous Formation Flight operations’ will hold a ‘final end-to-end demonstration’ flight in mid-2024, involving an A310 as the tanker testbed and DT-25 target drones as receiver aircraft.
Advanced concepts like Autonomous Assets Air-to-Air Refuelling and Autonomous Formation Flight could be potentially offered for future programmes like KC-Z, despite the USAF being unlikely to outline acquisition requirements for several more years, in advance of fielding a new aircraft in the 2030s.
‘I think there needs to be more analysis of exactly when some of these capabilities are going to be useful and under what circumstances,’ said Harrison. ‘Autonomous refuelling would seem to only be really useful if the platform itself can fly remotely and have a completely uncrewed tanker because that would mean the tanker can stay in the air much longer, because you don’t have the human factor limitation of aircrew becoming tired and fatigued.’
In this case an uncrewed tanker could potentially stay on station for 24h or more, although the issue of lubricating its engines might present a drawback, according to Harrison.
‘If other tankers simply continue to ferry fuel to the uncrewed aircraft, that sets up a whole new concept of operations, which lends itself to a new aircraft design for something like KC-Z, perhaps a smaller tactical tanker,’ he added.
However, in the near term, industry remains more focused on KC-Y. At a basic capability level, the fuel capacity of LMXT stands at 271,700lb (123,240kg), providing a superior lift than the 212,299lb (96,297Kg) of the KC-46. Moss also noted that the aircraft would also serve as a communications node alongside meeting more traditional tanker and refuelling demands.
‘We have stated to USAF that we’ve the power and space on board [LMXT] to make it an extremely robust tactical data link aircraft,’ he explained. ‘We’ve proven on other projects the ability to integrate multiple data links and connect ground, space, air and sea systems to seamlessly integrate the joint force to make sure that everyone is sharing the same information at the speed of relevance, so that they can prosecute joint operations most effectively.
‘Until the air force lays out exactly what they envision for the Advanced Battle Management System or the Joint All Domain Command and Control networks… we’ll show communications are within our scope of work.’
For receiver aircraft, future missions look set to increase dependence on tankers as new air defence systems and the extended range of operations makes refuelling all the more necessary. In the case of the USAF, the priority in planning for a conflict in Asia-Pacific with China, including an expected high operational tempo of tankers, remains at odds with reality and the damage to readiness caused by fixing the KC-46’s Remote Vision System (RVS) – as the remodelled RVS 2.0.
‘The way the [original KC-46] contract was let, was bad business on the part of Boeing to undercut the competition’s bid so badly that they had to absorb extra runaway costs,’ said John Venable, senior research fellow, defence policy, Center for National Defense at the Heritage Foundation.
‘It’s a firm fixed-price contract as opposed to a cost-plus fixed fee contract. If the air force had made it a cost-plus fixed fee, then they would have absorbed more of the financial risk. The air force made in their mind a great business deal, but at the cost of operations.’
He added that the number of ‘viable tankers’ available for USAF operations will be below 400 aircraft over the next three to four years and ‘stay there for a while’.
Putting that number in perspective, Venables said that in order for the US to execute a war with China, 580 tankers would be required. ‘The US only being able to operate over 300 rests with the poor contract and poor execution by Boeing,’ he added.
One other major operational concern for the USAF, as it thinks of how best to fight against China, is that much of the Western Pacific may ‘simply be off limits to tankers’, based on China’s military strategy to prioritise the disruption of enemy aircraft, according to Aboulafia.
‘Maybe they’ll [USAF] have to depend on some kind of new drone or stealth aircraft, an MQ-25 derivative or similar, because it’s possible that jetliner-size tankers won’t be survivable beyond a certain point,’ he added.
The USAF incurring greater financial risk once the RVS is fixed also compounds matters. To this point, Boeing has footed the bill for the RVS redesign and incurred especially hefty costs in the process. It recorded a $402 million pre-tax charge on the KC-46 programme, according to figures from Q4 2021 company earnings and lost a total of $1.3 billion on the acquisition in 2020, including a $275 million charge based on ‘production inefficiencies’ and COVID-19 disruption.
‘So far, the air force has successfully extracted $5 billion from Boeing funding,’ said Aboulafia. Once RVS 2.0 begins to be fielded – scheduled for Q4 2023 – the USAF will fall liable for any additional technical issues that could arise, a dramatic change to affairs.
‘When Boeing finishes fixing it [RVS 2.0] and delivers it to the air force, the air force has to accept that, and anything that’s wrong with it from that point forward, the air force has agreed to pay for,’ explained Venable. ‘There’s no incentive for Boeing to spend a lot of money [thereafter]. That [scenario] has the potential for a much longer period of operational risk, where the air force continues to retire tankers while accepting those that you can choose to use in peacetime.
‘But if you use them in combat situations where folks will be out of gas when they hit the boom, and that tanker cannot pass the gas, you’re going to start losing jets, that’s operational risk we can’t afford.’
RVS 2.0 should put an end to concerns over the cameras in the existing system suffering from sun glare or changing light conditions, causing display screens to black out, which has led air refuelling operators to struggle to accurately identify receiver aircraft receptacles and then fail to guide the boom in.
‘While there have been big cost overruns and serious delays, the KC-46 programme seems to be more on less back on track,’ said Aboulafia.
Such a perspective makes sense when Boeing’s delivery record is considered, with 61 aircraft handed over to the USAF since January 2019 and as of June 2022, the KC-46’s operational capacity increasing to support 97% of USTRANSCOM refuelling requirements, up from a lowly 8% in July 2021.
The latest operational capacity progress, approved under a seventh USAF Interim Capability Release (ICR) mission set, means that the tanker can now refuel the B-1B Lancer, C-135 series, E-8 JSTARS, EC-130H Compass Call, F-35B/C fighters, the KC-10 Extender and P-8 Poseidon aircraft.
That list expands on receiver aircraft previously approved including F-15, F-16 and F-22 fighters, C-130J airlifters, E-3G AEW&C aircraft and C-5M transports.
‘The KC-46A is supporting global, real-world theatre operational missions, including highest-priority missions such as Presidential support and the European air policing action,’ said a Boeing spokesperson.
‘The US Air Force KC-46A is also operationally approved to refuel a growing number of international receivers, strengthening global interoperability. As of July 2022, it has delivered more than 84 million pounds of fuel globally and flown more than 9,500 sorties.’
While such developments tell of much needed improvements for the KC-46, at a wider level, concerns surrounding USAF’s tanker modernisation plans and operational capacity still abound.
‘There are not sufficient numbers in the Future Years Defense Program to meet the needs of the nation’s defence strategy,’ explained Deptula. ‘If you look at operational demands, the tanker force is stressed today. We can’t redeploy fighters from training assignments because there are other priorities for airlift which demand tankers as well.’
‘There are not sufficient numbers in the Future Years Defense Program to meet the needs of the nation’s defence strategy.’
Without additional funding, the long-term prospect of the USAF dramatically reshaping tanker procurement and more easily fulfilling operational demands looks to be unrealistic.
Holding off on a decision about KC-Y could be looked upon as a risky move that causes further disruption to acquiring new tankers. However, analysts appear to think that this encourages Boeing to keep on top of its performance with respect to the KC-46 programme and potentially gaining a follow-on order.
Alternatively, if the USAF eventually decides to buy an LMXT fleet from Airbus and Lockheed Martin, it cannot afford to hold off on formally introducing the KC-Y acquisition any longer, not least for funding reasons.
‘It takes about three years from the first rivet to the final coat of paint [to manufacture LMXT], so that’s why it’s really important, if the air force wants [KC-Y operations to begin in] 2029, then 2025 has to be the timeframe for testing,’ said Moss.
However KC-Y plays out, the bleak reality for the air force is that it must also make good on a whole raft of other programmes including the introduction of new B-21 Raider bombers and E-7 AEW&C aircraft while committing to investment in the ICBM-based LGM-35A Sentinel/Ground Based Strategic Deterrent.
Though it is much too early to predict which aircraft will be on offer should KC-Z receive approval beyond 2030, the consensus among industry observers indicates that autonomous technologies will be integrated, while future tankers are also likely to be tasked with C2 and ISR missions as opposed to only refuelling receiver aircraft.