Do We Need Aerial Tankers?

Do we really need carrier based, aerial tankers?  Your immediate reaction is, of course we do!  However, let’s hold off before we make that our final answer and take a moment to look just a bit closer at the tanker question.
 
Let’s start by answering the most basic question:  why do we have tankers, currently?  This is not a trick question.  There are two general answers:
 

• Overhead Tanking provides tanking for overhead aircraft who need a just a bit of extra fuel to get back aboard the carrier.  Perhaps the pilot had to execute one too many wave offs and go-arounds and has run just a bit low on fuel or maybe the aircraft came back from the mission low on fuel due to any number of possible reasons.  Those aircraft need fuel.
• Mission Tanking extends the reach of a mission.  WWII aircraft were limited to a range of whatever their onboard fuel tank allowed them.  Tanking is a means of extending the range of an aircraft by refueling during the mission.

 
Understanding those two basic requirements, let’s look a bit deeper and bit further into the future of tanking.
 
 
Mission Tanking
 
Let’s start with the mission extension requirement.
 
Here’s a question you may not have previously considered:  what determines the maximum range of a mission?
 
Simplistically, the range is determined by the aircraft’s unrefueled range plus any aerial refueling provided as part of the mission … but is that the whole story?  Since we’re doing a post on this, you can assume it’s not!
 
If fuel were the only determinant of range, we could, in theory, have carrier aircraft fly global missions.  The carriers could stay in port, launch aircraft, and those aircraft could strike/fight on the other side of the world;  after all, it’s just a matter of sufficient refueling events, right?  However, a moment’s thought suggests that the pilot of a single seat aircraft can’t remain awake, alert, and combat effective beyond a certain number of hours in the cockpit.  Anyone who’s driven long hours in a car understands the debilitating effect of cramped quarters even with occasional pit stops for relief, food, rest, and just to stretch one’s legs.  How much worse must it be for a pilot who, literally, is strapped in and can’t move or stretch, and struggles even to relieve himself.  At some point, the pilot becomes combat ineffective.  It’s analogous to the infantryman who quickly becomes ineffective in a landing craft due to seasickness after a brief period.
 
What is the time period beyond which a pilot becomes combat ineffective?  I don’t know – and it will vary somewhat from person to person – but a reasonable estimate is around three hours.  Beyond that point, the pilot begins to lose effectiveness.  Sure, there’s nothing like the adrenalin surge of combat to wake one up but there’s no escaping the underlying decrease in alertness, reflexes, and mental agility (which declines precipitously with fatigue).  A less than completely optimal pilot is another way to describe a dead pilot.  This is not to say that a mission longer than three hours can’t be accomplished but you’re dipping into diminishing returns at that point.  Diminishing returns is another way to describe a dead pilot and failed mission.  Modern combat requires 100% efficiency in order to have a hope of survival and success.  This, by the way, is the main reason why modular ships are inherent failures – they’re not 100% optimized.  But, I digress …
 
Let’s set aside range limitations and consider enemy threats.  Submarines, cruise and ballistic missiles, supersonic aircraft, very long range SAMs, and the like have resulted in being forced to doctrinally move our carriers further and further back from the target.  We’re now talking about having to operate many hundreds of miles away or even out to a thousand miles or more.  What does that do to the mission time frame?  Using subsonic aircraft with, say, a cruise speed of 550 mph, it would take 3.6 hours to fly a thousand mile, straight, out and back mission.  Now, throw in realistic time delays for departure assembly at the carrier, tanking, non-linear routes, in-flight refueling, actual mission execution time (air to air combat or loitering), landing pattern time, etc. and that bare minimum of 3.6 hours becomes something on the order of five hours.  Wait … what did we say about cockpit time beyond which a pilot’s performance begins to degrade?  Yeah, something on the order of three hours.  Uh, oh …
 
Returning now to the tanker issue, we can see that simply adding tankers to provide longer and longer ranges is not a correct or viable approach.  Tanking is beneficial only until it extends the mission time beyond the magic three hour limit.  After that, it becomes counterproductive.  Thus, even if we had a tanker that could deliver infinite fuel at infinite range, it would be useful only within fairly narrow constraints. 
 
The pilot’s combat effectiveness is the limiting factor, not fuel !
 
Thus, bigger, better, longer ranged tankers are not the answer beyond a certain point.
 
Note:  An almost semantic variation of the range extending, mission tanking is station time extension where we want to keep an aircraft on station for an extended time at a shorter range.  For example, an aircraft flying cap at, say, 300 miles, might need refueling to enable it to loiter on station for a couple hours even though it has sufficient onboard fuel for the 600 mile round trip.
 
 
Overhead Tanking
 
Not much to say about this.  Overhead/recovery tanking is a mandatory aspect of carrier operations.  There’s no getting around the need.
 
 
Conclusion
 
Single seat aircraft are constrained by the physical and mental fatigue limits of the pilot.  As we noted, a thousand mile mission is about the limit of a pilot’s combat effectiveness.  Thus, our attempts to design and build aircraft with combat radii greater than a thousand miles and/or to provide tankers that can extend missions beyond a thousand miles are pointless.
 
Of course, if our aircraft have only an inherent combat radius of, say, 200 miles then, yes, we need to provide tanking to accomplish a thousand mile mission.  However, we have, in the past, built aircraft with unrefueled, thousand mile radii, or nearly so, so that should be our design goal.  An aircraft with a thousand mile unrefueled radius pretty much eliminates the need for mission tanking except in the extreme of, say, maximum range, air-to-air combat which requires full power/afterburner once arriving on station.
 
The conclusion is that, yes, we most definitely need tanker aircraft but we need to be careful to recognize that we’re bumping up against pilot limitations, not fuel limitations.  This recognition should impact our tanker needs (number, size, capacity, etc.) and design.
 
 
 
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Note:  I selected a value of three hours as the point beyond which a pilot becomes ineffective.  It could be two hours, or four, or 3.187.  The exact value doesn’t change the premise and there is no exact value, anyway, since it would vary from pilot to pilot and would depend, in part, on the circumstances of the mission.  Therefore, I’m not going to entertain debates about the exact value.  Fair warning!

MQ-25 Control

The Navy’s new, not yet active, MQ-25 unmanned tanker is a fascinating control scheme case study.  You may recall that it began life as a combat UCAV concept which then morphed into a combined strike/ISR, then a pure ISR, then a combined ISR/tanker, and, ultimately, into a pure tanker … with occasional rumors of ISR or strike capabilities still being possible with minor modifications.  That convoluted development path alone makes for a fascinating story but there’s another aspect of the MQ-25 that is equally fascinating and, as best I can tell, completely ignored and that is the control scheme required to operate the tanker and how that control scheme impacts the concept of operations (CONOPS).
 
The closest I’ve seen to a CONOPS is the vague, general requirement that the tanker should be capable of delivering 14,000 lbs of fuel at a distance of 500 miles (variously reported as 15,000 lbs at 500 nm, depending on the source).  Of course, that’s not even remotely a CONOPS;  it’s a capability and an ill-defined one at that.
 
Moving on …
 
The MQ-25 consists of two main components: the MQ-25 air vehicle and the MD-5 Ground Control Station (GCS).
 
In a bit of a first for a major program, the government is acting as the lead integrator.  I applaud that, however, there won’t be any manufacturer to blame if it does not go well!
 

The Navy’s Unmanned Carrier Aviation program office (PMA-268) is moving forward with integrating its two key elements—the MQ-25 air vehicle and the MD-5 Ground Control Station (GCS) at the program’s System Test and Integration Lab (STIL) at Patuxent River.[1]
 
PMA-268 is the lead systems integrator, working closely with its two prime industry partners, Boeing  and Lockheed Martin Skunk Works … [1]
 
“This will be the first time we are integrating an air vehicle and GCS from two different prime contractors,” said T.J. Maday, MQ-25 labs and integration manager.[1]

 
Airframe development aside, the challenge is to integrate the aircraft and the GCS with the various control ship’s sensors and software.  Many levels of integration are required – no easy task.
 
 
Control Scheme
 
There is no direct ‘pilot’ control of the MQ-25.  A ground ‘pilot’ does not fly the aircraft as is done with other UAVs.  Instead, the MQ-25 will be controlled via general commands which the aircraft’s software will attempt to implement … eventually … as the immediate situation allows.  The analogy would be someone telling you to buy milk from the grocery store but they don’t give you exact, second by second instructions.  You’re given a general command and left to figure out the details and exact timing of how to go about it yourself.
 

… the AVO [air vehicle operator] is never intended to directly input singular controls to the AV, combined with the expected signal delay, this is omitted … [2]
 
AVOs will input large scale commands such as a flight path or holding pattern, an altitude or direction change while running concurrent systems like the Stingray’s fuel pod or landing gear. “The logic within the aircraft will resolve [these] requests as compatible with its current phase of flight … [2]

 
This kind of ‘execute when you can’ control is fascinating.  Consider the simple example of a command to turn to a new heading, say, 90 degrees off.  Seems simple enough, right?  But, what if an aircraft is being currently refueled?  The UAV might be wise to delay execution of the heading change until after the current aircraft finishes tanking.  On the other hand, what if the turn command is the result of an enemy threat dead ahead?  Maybe the UAV should turn very soon and very sharply?  In fact, maybe it should terminate the refueling?  Maybe there’s another friendly aircraft that needs refueling on a fairly high priority but not an emergency?  Should the UAV continue tanking or break off and disrupt the current aircraft’s plan and timing?  What’s the current aircraft going to do with the fuel it receives?  What’s the priority?  And so on … 
 
As you see, the variations to even this ‘simple’ command are infinite.  Can we write software that can correctly assess and evaluate all the possibilities?  That strikes me as no easy task considering that, for example, we’ve been working on the ‘simple’ F-35 logistics software (ALIS) for decades and have failed miserably and the F-35 Block 4 software has been largely abandoned due to failure to complete it.
 
Alternatively, what if the UAV receives no command but there is a threat dead ahead?  Does the UAV have the sensors and software to detect and interpret a threat on its own and then make an intelligent response?  While we’d like to believe that the person controlling the tanker will be omniscient and aware of all threats and command the UAV accordingly, that’s pure fantasy in actual combat.  Some threats will be detected but others will be missed or detected too late.  What if an aircraft in distress needs fuel but can’t contact whoever the UAV controller is?  With a manned tanker they might be able to contact the tanker pilot directly and request help but you can’t talk to a UAV.
 
 
Signal Delay
 
Did you note the reference in the quote to ‘expected signal delay’?  This, too, is intriguing.  We’ve come to believe that any remote, unmanned control is instantaneous and this would appear not to be the case, at least not for the MQ-25.  I don’t know what particular component of the control scheme introduces delay or what the length of the delay is. 
 
This signal delay is similar to the widespread and misguided belief that satellites provide instantaneous detection and weapons launch control against ships.
 
Consider the example of a late detected threat described above.  The pilot of a manned aircraft can react instantly when the undetected threat eventually materializes.  A UAV, especially one with a signal delay built in, cannot react instantly.  We may lose tankers while the UAV flies blithely on, uncomprehending and uncommanded.
 
It is also unclear to me whether the expected signal delay is an inherent, unavoidable characteristic of the system components or whether it’s a conscious decision that real time control is not needed.  Fascinating, either way!
 
Regardless, the approach is a wise one, in the sense that trying to control a UAV in real time in combat is not consistently possible and it is probably counter-productive to even try.  Of course, this only works if the software can be made smart enough to resolve and manage the potentially conflicting or contradicting commands the UAV will receive.
 
It is significant that there is no official mention of MQ-25 control by other airborne assets although the Navy has expressed interest in such alternate control.  At the moment, the only control is via the GCS stations which will reside on the carriers.  However, consistent with its obsession with the ‘any platform/sensor/weapon can network with any other platform/sensor/weapon’ philosophy, it now appears that the Navy is trying to make the MQ-25 controllable by other aircraft.
 

Boeing is also working with the Navy so that an airborne platform can control the MQ-25 Stingray and not just from its aircraft carrier home. When speaking about this, Rear Admiral Telford said:  “MQ-25 needs to have the ability to talk and be managed by any airborne platform, including those of our allies and partners.”[3]

 
Communications Security
 
We noted in a previous post that the desire to control the MQ-25 from other airborne assets was rooted in a fundamentally illogical assumption about communications security (see, "MQ-25 Control Concept"). 

The value in pilots being able to task MQ-25s mid-flight lies within a core assumption the Navy — and more broadly the Pentagon — has about the future battlefield: all communications will be subject to attack. The shipboard controllers may not always have contact or permission to communicate with the MQ-25 depending on the situation. If that’s the case, then a pilot of a nearby manned aircraft may need to redirect the unmanned tanker without assistance from the ship.

Of course, this raised the question, if the shipboard controller can’t communicate with the unmanned tanker due to enemy disruption of communications, why would we think that we’ll be able to communicate with the manned aircraft to tell the pilot to redirect the unmanned one?  That’s a logical inconsistency.  Military thinking just teems with this kind of logical inconsistency.
 
 
Issues
 
Communications – Regardless of the degree of communications with the MQ-25, how secure are the communication links?  Will the regular, if not constant, communications, back and forth, betray the UAV, carrier/control asset, or both locations?  Every person I’ve talked to who knows anything about signals intercept states unequivocally that our comms are nowhere near as secure as we like to believe.
 
For that matter, what type of communication signal will the MQ-25 use?  Satellite relay?  LOS?  Omni-directional?  Multiple modes?
 
Cyber Security – Anything that can receive a signal can be cyber attacked and the MQ-25 certainly qualifies.  At a minimum, the aircraft will have sensors taking in external signals and dedicated communication and data link receivers.  We don’t want a Battlestar Galactica scenario but, as we’ve seen repeatedly, even the best protected network or computer can be hacked and on a fairly regular basis.  Hardly a month goes by that I don’t receive a letter from some company saying that my customer data has been compromised and that’s from major corporations who claim to have secure networks!  China is working every day to find and develop cyber vulnerabilities in our assets.  Can an unmanned platform function reliably in the face of cyber threats? 
 
Ground Control vs. Aircraft Control – Both approaches have pros and cons, as we’ve discussed.  One further aspect of the discussion is that if you need an aircraft to control the tanker, you’ve essentially turned the ‘one-man’ tanker operation into a multi-aircraft procedure.  Requiring two aircraft to enable one to be a tanker is horribly inefficient and, essentially, doubles the cost while requiring twice the resources.
 
CONOPS – I desperately hope the Navy has thoroughly worked through the CONOPS under realistic conditions before concluding that the MQ-25 was the best solution.  My fear (near certainty) is that they hopped on board the unmanned tanker in a technology-for-the-sake-of-technology move and that an unmanned tanker is not the best solution.
 
 
 
 
 _____________________________ 
 
Note:  Fleet service timeline has been pushed back to 2026 or later.
 
 
______________________________

 
[1]Navair website, “MQ-25 team preps for first air vehicle, control station integration test event”, 18-May-2022,
https://www.navair.navy.mil/news/MQ-25-team-preps-first-air-vehicle-control-station-integration-test-event/Wed-05182022-0715
 
[2]Forbes, “Developing The MQ-25’s Ground Control Station Means Thinking Like A Mission Commander - Not A Pilot”, Eric Tegler, 12-Jan-2021,
https://www.forbes.com/sites/erictegler/2021/01/12/developing-the-mq-25s-ground-control-station-means-thinking-like-a-mission-commandernot-a-pilot/?sh=643ac901557a
 
[3]Simple Flying website, “Pushing Boundaries: What Is The Boeing MQ-25 Stingray?”, Mark Finlay, 13-Feb-2024,
https://simpleflying.com/boeing-mq-25-stingray-guide/

MQ-25 Control Concept

The Navy’s unmanned tanker, the MQ-25, is supposed to be able to take off, fuel aircraft, and land, all autonomously.  That’s quite an accomplishment and, if successful, adds a vital tanking capability without adding remote pilots or requiring complicated control communications schemes which would add to the burdens of a carrier rather than subtracting from them.  It is the hands-off nature of the unmanned tanker that is appealing.

 

However, the latest rumblings from the Navy hint at a somewhat different story.

 

Boeing has successfully demonstrated for the first time the ability for the P-8A maritime patrol aircraft to take control of the MQ-25 Stingray drone mid-flight …

 

The event was a follow-up to a demonstration to one the company held last year which showed how the Stingray, the Navy’s new carrier-based, unmanned aerial tanker, could be controlled by an F/A-18 Super Hornet or E-2D Advanced Hawkeye pilot mid-flight while performing its core tanking mission.[1]

 

This is moving into dangerous territory.  Is this suggesting that a supervisory aircraft will need to be present in order for the unmanned tanker to perform its task?  That would be a very disappointing development – almost an overall negative for a carrier air wing that has few enough aircraft, as it is, and can ill afford to dedicate a control aircraft to babysit an unmanned tanker.

 

However, I think this suggesting that the Navy could, via an intermediary aircraft, take control of a tanker in order to issue new mission orders.

 

The value in pilots being able to task MQ-25s mid-flight lies within a core assumption the Navy — and more broadly the Pentagon — has about the future battlefield: all communications will be subject to attack. The shipboard controllers may not always have contact or permission to communicate with the MQ-25 depending on the situation. If that’s the case, then a pilot of a nearby manned aircraft may need to redirect the unmanned tanker without assistance from the ship.[1]

 

Of course, this raised the question, if the shipboard controller can’t communicate with the unmanned tanker due to enemy disruption of communications, why would we think that we’ll be able to communicate with the manned aircraft to tell the pilot to redirect the unmanned one?  That’s a logical inconsistency.  Military thinking just teems with this kind of logical inconsistency.

 

Here’s a bit of additional delusion and logical inconsistency:

 

“If you’re doing an ISR mission, you can be doing an ISR mission with this airplane [the unmanned tanker] 1,000 miles from the carrier,” he said. “You’re not going to be talking to the carrier to do that ISR mission. More than likely you might be talking to a P-8.”[1]

 

If you believe a large, slow, non-stealthy, broadcasting surveillance aircraft like the P-8 is going to survive to operate a thousand miles from a carrier, in enemy controlled/contested air and water, you’re deluding yourself.  And, in a bit of logical inconsistency, if you can survivably operate a P-8 in the area then you don’t need an unmanned tanker/surveillance aircraft because the P-8 can do it.

 

This attempt to redirect and repurpose an unmanned tanker into other missions is typical of the Navy.  Instead of developing a single function and getting it to work at an affordable price, the Navy is already attempting to add additional tasks and control schemes onto an as yet unproven aircraft.  Common sense says to develop the main functionality first before moving on to others.

 

 

 

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[1]Breaking Defense website, “Boeing successfully demos MQ-25 control through P-8, autonomy software”, Justin Katz, 8-Sep-2022,

https://breakingdefense.com/2022/09/boeing-successfully-demos-mq-25-control-through-p-8-autonomy-software/

! ! ! !

This is not a Navy issue but it warrants a notice.  The Boeing KC-46 tanker program has had lots of problems and the manufacturer has taken massive losses.

... KC-46 losses now total more than $5 billion on a $4.9 billion contract ... [1]

Boeing has lost more than the contract was worth !

KC-46 Tanker [1]

Sooner or later, the various military and industrial contracting parties have got to learn some lessons such as:

• Don't design products that are more complicated than they need to be.  Seriously, it's a tanker.  It's a flying fuel tank with a pump for transferring the fuel.  We've been doing this for how many decades?  But no ... we had to make the new tanker an all-digital, remote vision, automated, fly-by-wire boom, with super glass panoramic displays.  In addition, we couldn't just have it dispense gas.  No, that would be too simple and cheap.  We had to make it a multi-function, combination tanker, passenger transport with seating for 58, cargo transport with capacity for 18 pallets, and medevac with room for 54 patients.[2]
• Don't low ball bids[1]
• Don't accept bids that are obviously unrealistic.  The Air Force is just as much to blame as Boeing.
• Don't ask for and don't offer fixed price bids for unproven products.
• Demand prototypes and test them thoroughly before issuing contracts.

The Air Force may think they were clever by using a fixed price contract but what did they gain?  The program began in 2001 and Boeing was selected in 2011.  Now, 11 years later, the Air Force has yet to receive new functional tankers.  The Air Force may not be footing the bill for the problem fixes and schedule delays but they aren't receiving any product, either.  So, what did they really gain?

[1]https://breakingdefense.com/2022/07/new-boeing-defense-ceo-signals-different-approach-in-future-fixed-price-contracts/

[2]https://en.wikipedia.org/wiki/Boeing_KC-46_Pegasus

Navy Aerial Refueling

As you know, the Navy is struggling with aerial refueling and some time ago made the unbelievably stupid decision to use its newest, most capable, front line strikefighter as a tanker.  This decision has resulted in several F-18E/F’s in each air wing being removed from combat service and the aircraft being prematurely worn out due to the greatly extended flight hours of a tanker.

This idiocy prompts us to look back at the history of Navy aerial refueling.

Surprisingly, the history of Navy aerial refueling is fairly short.  As best I can tell, here’s a chronological list of the dedicated tanker aircraft that the Navy has used over the years.  Various other aircraft have been used for occasional buddy tanking but these are the dedicated tankers even if they weren’t purpose built for the task.

	Operating Period	Deliverable Fuela
KA-3B Skywarrior	1967- mid 1970s	29,000 lb
KA-6D Intruder	early 1970s – late 1990s	20,000 lb
S-3 Viking	late 1970s – late 2000s	16,000 lb
F/A-18E/F Super Hornetb	early 2000s - current	14,000 lb
MQ-25 Stingray	2024? - ?	14,000 lb

^a Deliverable fuel is a highly variable number which depends on the distance the tanker has to fly to reach the refueling point and how much, if any, of the tanker’s internal fuel is available for off-load.  The figures presented are approximate estimates under typical conditions.

^b The Super Hornet is sometimes cited as being able to carry around 29,000 lb of fuel but that includes both internal fuel and all five external fuel tanks.  Under actual conditions, the Hornet cannot deliver all of its internal fuel and the Navy no longer operates the Hornet with all five fuel tanks due to increased stress and wear on the aircraft.  Thus, the actual deliverable fuel is much less.

Here’s some interesting tidbits of information about the various tankers.

KA-3B Skywarrior

• 85 A-3B bombers were refitted in 1967 for the tanker role
• The KA-3 could deliever 29,000 lb of fuel at 460 miles (1)

Skywarrior Refueling Intruder

KA-6D Intruder

• 90 A-6As and A-6Es were converted for use as tanker aircraft
• Could deliver half the load of the KA-3B Skywarrior (1)
• Could deliver a maximum of around 3000 gal (20,000 lb) (5)
• Could carry 5 external fuel tanks (4 wing + 1 centerline) and dispensed fuel from buddy tanks or a centerline hose/drum refueling basket which could transfer fuel from the external tanks or the aircraft’s internal tanks
• First demonstrated in 1966.

KA-6D Intruder

S-3 Viking

• A single KS-3A prototype was developed and tested but the program was cancelled
• The original proposed KS-3A Viking tanker would have added a conformal weapons bay fuel tank to supplement standard external buddy tanks which would have allowed the aircraft to carry 30,000 lb of fuel (2)
• S-3 Vikings were used as dedicated buddy tankers able to deliver around 16,000 lb of fuel (2)

S-3 Viking Tanker

F/A-18E/F Super Hornet

• Older A-D model Hornets were not equipped for tanking so only the more modern E-F models were used
• Anywhere from 25 to 30 percent of Super Hornet sorties are used for refueling missions (4)
• The Hornet Aerial Refueling System includes an external 330 gallon tank with hose reel on the centerline along with four external 480 gallon tanks and internal tanks for a total of 29,000 pounds of fuel on the aircraft, however, the Navy has had to reduce the number of external fuel tanks in the tanking role due to excessive wear on the airframes (6) and this reduces the deliverable fuel which, in turn, requires more Super Hornets to be used as tankers to dispense the same amount of fuel

F-18F Tanker

MQ-25 Stingray

• Refueling specification is to offload 14,000lbs of gas at a distance of 500 miles
• IOC won’t occur until 2024 and that target is subject to up to a three year delay due to carrier test ship modernization delays (3)
• Navy plans to buy around 70 production aircraft
• The 2020 GAO annual report cites a unit cost (includes procurement and development) of $146M per aircraft and notes that costs could rise substantially if carrier modernization is delayed
• Eisenhower (CVN-69) and Bush (CVN-77) have been designated to be the first two carriers to test and operate the MQ-25 but each requires modernization and installation of unmanned aircraft control stations, data links, and maintenance facilities.  If the upgrade schedule cannot be met – and it’s currently in doubt – the MQ-25 introduction faces a several year delay.

MQ-25 Stingray

Here’s a few general bits of information:

Aerial refueling dates back to the 1920’s beginning with early attempts to refuel biplanes.

In 1934, Sir Alan Cobham had founded Flight Refuelling Ltd which began refining the probe-and-drogue system commonly used by the Navy, today.

The Intruder and Super Hornet provide tactical refueling capability in that they are capable of accompanying strike groups rather than having to meet them at designated locations.

The KS-3A Viking original proposal would have provided significant refueling capacity (up to 30,000 lb) and, if implemented, could have saved the Hornets from being forced into tanker duty.  Even today, some 90 S-3 Vikings are still available in long term storage and most have used only around half of the lifetime flight hours.  They could still be converted into KS-3 Viking tankers for much less than the cost of developing the new MQ-25 Stingray, one supposes.

Here’s an example of typical tanker usage:  During Vietnam, strike forces launched from aircraft carriers in the Gulf of Tonkin were accompanied by tankers for a final refueling before they went to the target. Tankers were held in standby orbits for attackers returning from the target, and a tanker was always in orbit over the aircraft carrier in the event a returning airplane, almost out of fuel, missed its "trap" and had to circle for a second attempt at landing.(1)

The future of Navy aerial refueling, assuming the MQ-25 Stingray pans out, is mediocre, at best.  The MQ-25 deliverable fuel is at the lower end of the historical capability spectrum which means that more aircraft will be required to deliver the required quantity of fuel.  Of course, given that air wings have shrunk to nearly half their original size, there is plenty of room on the carriers for extra aircraft.  Whether the MQ-25 can operate tactically with strike groups or will have to establish refueling locations remains to be seen.  The MQ-25 seems to be a decidedly average capability.  If the aircraft can be procured at sufficiently cheap prices and the operating costs are not excessive then the mediocre capability is acceptable.  Unfortunately, the $146M unit cost is extremely high and costs always increase so this is looking to be poor value for the dollar.

That’s it.  Other than the obvious conclusion that the Navy chose the absolute worst path for aerial refueling (not surprising), this is primarily just an informational post to help us understand what our aerial refueling situation is, how we got there, and what our future prospects look like.

_________________________________

(1)Global Security website, “KA-3B / EKA-3B”,

https://www.globalsecurity.org/military/systems/aircraft/ka-3b.htm

(2)The Drive website, “The Compelling Case For Turning S-3 Vikings Into The Navy's New MQ-25 Tanker Drone”, Tyler Rogoway, 6-Apr-2018,

https://www.thedrive.com/the-war-zone/19789/the-insanely-logical-case-for-turning-s-3-vikings-into-the-navys-new-mq-25-tanker-drone

(3)Defense News website, “If the US Navy isn’t careful, its new unmanned tanker drone could face a 3-year delay”, David B. Larter, 11-Jun-2020,

https://www.defensenews.com/naval/2020/06/10/if-the-us-navy-isnt-careful-its-new-unmanned-tanker-drone-could-face-a-3-year-delay/

(4)USNI News website, “Navy Has Picked the First Two Carriers to Fly MQ-25A Stingray Unmanned Aerial Refueling Tankers”, Sam LaGrone, 12-Jun-2017,

https://news.usni.org/2017/06/12/navy-has-picked-the-first-two-carriers-to-fly-mq-25a-stingray-unmanned-aerial-refueling-tankers

(5)A-6 Intruder, Detail and Scale, Vol.24, Bert Kinzey, 1987, p.58

(6)USNI News website, “Navy Getting ‘Smarter’ About Tanking Mission As Super Hornets Approach 6,000 Hours”, Megan Eckstein, 12-Aug-2015,

https://news.usni.org/2015/08/12/navy-getting-smarter-about-tanking-mission-as-super-hornets-approach-6000-hours

Northrop Pulls Out Of Unmanned Tanker Competition

Northrop has announced that it is pulling out of the competition to build the Navy’s MQ-25 unmanned tanker.  As you recall, there were four competitors: Northrop Grumman, General Atomics, Boeing, and Lockheed Martin.  Northrop’s explanation is cryptic, to say the least.  Here’s the statement from Northrop CEO Wes Bush.

“When we’re looking at one of these opportunities, let me be clear, our objective is not just to win.  …we really look hard at executability under the terms of [requests for proposals] that come out to make sure that we can execute.” (1)

So, something in the Request For Proposals (RFP) made Northrop believe that they couldn’t meet the requirements.  This is all the more odd given that the RFP was structured to have very few actual requirements.  In fact, the only requirement that has been revealed is the informal statement by Navy personnel that the tanker would deliver around 15,000 lbs of fuel at 500 miles.

Northrop was assumed to propose their X-47 as the basis for their tanker.  In fact, given that the X-47 was used in actual carrier landing and takeoff tests, Northrop was assumed to have a huge advantage in the competition.  That they would feel that advantage was insufficient makes their decision even harder to understand.  If Northrop’s actual carrier UAV operational experience isn’t adequate to meet the RFP, what does that say about the other competitor’s offerings and capabilities?

Another possibility is that the X-47 is simply incapable of meeting the fuel capacity and distance requirements.  The flying wing type of UAV may be simply unsuited for the task.  Perhaps the stealthy body size and shape does not allow sufficient fuel carriage?

It is also possible that Northrop felt that a stealthy flying wing would be inherently more expensive than a more conventional wing-fuselage-tail design and unable to compete on a cost basis.  If so, it’s worth noting that the General Atomics design, the only other design we’ve seen, is a conventional design and may hold a cost advantage.

Recall, also, that we’ve discussed the vulnerability of non-stealthy support aircraft so stealth may be an attractive feature in an aircraft that is expected to operate hundreds of miles from the carrier and within range of enemy aircraft and long range missiles.  The Chinese are developing a very long range air-to-air missile for the explicit purpose of attacking high value support aircraft like the E-2 Hawkeye, AWACS, P-8, tankers, etc.

The other interesting aspect of this is that this is the second occurrence of major defense firms pulling out of contract competition.  You’ll recall that the Navy’s competition for the over the horizon (OTH) anti-ship missile saw all but one of the competitors pull out after the RFP was released.  We discussed this at the time (see, “LRASM Drops Out Of OTH Competition”) and noted that it was a development with several negative consequences, not the least of which was that the lack of competition was an invitation to price gouging by the only remaining competitor.  At the time, I speculated that the Navy had pre-selected the company that they wanted to win the OTH competition and had written the RFP so as to ensure that only that company could meet the requirements.  Could this be a similar case?  Has the Navy already pre-selected a winner?  If more companies pull out of the tanker competition then this may be what’s happening.

X-47 - Out!

I would hate to think that pre-selecting competition winners, if that’s what’s happening, is the latest Navy trend given all the negatives associated with such a practice.  Had the OTH competition fiasco not just occurred, I wouldn’t give Northrop’s actions, in this case, much thought but now this looks suspiciously like a trend towards pre-selecting winners.

Of course, it’s also quite possible that this is just a business/investment/financial decision by Northrop, pure and simple, in which case there’s nothing to be seen here and we can all move on.

We’ll keep a close eye on this competition and see what develops.

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(1)USNI News website, “Northrop Grumman Drops Out of MQ-25A Stingray Competition”, Sam LaGrone, 25-Oct-2017,

https://news.usni.org/2017/10/25/northrop-grumman-drops-mq-25a-stingray-competition

Navy Aerial Tanker Update

Details on the Navy’s MQ-25 Stingray unmanned tanker have been hard to come by, especially the most relevant ones like fuel loads and range.  Now, however, we see some details in a USNI News article (1).

“Air Boss Vice Adm. Mike Shoemaker said the service’s goal was for the Navy’s first operational carrier-based unmanned aerial vehicle to be able to deliver about 15,000 pounds of fuel at 500 nautical miles from the carrier to the air wing’s strike fighters, which would almost double their operational range.”

So, that’s interesting … 15,000 lbs of fuel at 500 nm from the carrier.  Let’s examine that a bit closer.

An F-18 Super Hornet has an internal fuel capacity of around 14,000 lbs.  So, the unmanned tanker could completely refuel one aircraft.  Of course, that’s not exactly how refueling works.  Each aircraft would receive a lesser amount of fuel, say 5,000 lbs.  Thus, the tanker could refuel three aircraft.  I think you can see where this is going.  If there are 30 aircraft in a strike package, and each needed 5,000 lbs of fuel, it would require 10 tankers.  That’s a LOT of tankers.  Of course, more tankers would be required for the carrier overhead/recovery tanking.  We’re looking at around 16 tankers in our strike/recovery scenario.  Yikes!

Now let’s refer back to that quote and the phrase, “double their operational range”.  Here’s the relevant range figure according to the article.

“The strike range of a carrier air wing is now only about 450 nautical miles – the effective unrefueled radius of a Boeing F/A-18E/F Super Hornet.”

That range figure is exceedingly optimistic but, hey, let’s work with it for the sake of discussion.

So, if it took 15,000 lbs of fuel to achieve an operational range of 450 nm, adding 5,000 lbs of extra fuel (36% of the aircraft’s full fuel capacity) isn’t going to double the aircraft’s range, it’s going to increase the range by 36% which is an extra 160 nm.  Yes, I know the range calculations aren’t a simple linear function.  I’m just illustrating the concept.  No matter how you look at it, we aren’t going to double an aircraft’s range by adding a small fraction of additional fuel.  The only way we can double the range is to do a complete refueling which takes us back to a 1:1 tanker:aircraft ratio.  In that case, our example strike of 30 aircraft would require 30 tankers!

Does no one in the Navy run these simple calculations?  Apparently not.

Let’s refer back to the excellent post by guest author George Bustamante, “Why The Navy Needs A Really Large Tanker” (2).  In that article, he lists fuel capacities of various tankers and demonstrates why a capacity of 15,000 lbs of fuel is insufficient for a mission tanker.  For example, the old KA-3 Skywarrior tanker carried 29,000 lbs of fuel  - almost double that of the proposed unmanned tanker.  At the high (and useful) end, the KC-135 carries 150,000 lbs!

The MQ-25 Stingray, with a 15,000 lb fuel capacity barely duplicates the current F-18 Super Hornet tanker capacity of ~16,000 lbs.  The F-18 isn’t considered a mission tanker so how will the MQ-25 which barely duplicates the F-18 tanker’s load suddenly and magically become an effective mission tanker?  Unless we’re going to build lots and lots of these unmanned tankers, I just don’t see this as an effective solution for mission tanking – for overhead/recovery tanking, yes, but mission tanking, no.

So, we have fraudulent claims about doubling the air wing’s range combined with an utterly ineffective mission tanker specification.  I don’t see a good outcome, here.  Yes, it can free up the Hornet from overhead/recovery tanking, which is good, but it leaves the Navy with short ranged aircraft and still no effective mission tanker.  The Navy had an opportunity to do something that could significantly enhance the air wing’s combat effectiveness and apparently have declined to do so.  Baffling.

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(1)USNI News website, “MQ-25 Stingray Unmanned Aerial Tanker Could Almost Double Strike Range of U.S. Carrier Air Wing”, Sam LaGrone, 31-Aug-2017,

https://news.usni.org/2017/08/31/mq-25-stingray-unmanned-aerial-tanker-almost-double-strike-range-u-s-carrier-air-wing

(2)Navy Matters blog, “Why The Navy Needs A Really Large Tanker”, George Bustamante, 22-Aug-2016,

http://navy-matters.blogspot.com/2016/08/why-navy-needs-really-large-tanker.html

Carriers And Tankers

The recent post about the Navy’s proposed unmanned tanker, the MQ-25 Stingray (see, "Navy Issues Tanker RFP"), engendered a lot of discussion about tankers, the various aircraft that could fill the role, and the need for tankers, in general.

Before anyone goes any further with this, it is mandatory to reread the excellent article on mission tanking written by guest author Mr. Bustamante (see, “Why The Navy Needs A Really Large Tanker Aircraft”).

Now that you've done that, let's move on.

All of our tanker aircraft discussion is missing one key point – the only point that really matters, actually – and that is the role of the carrier.  To make the point with a ridiculous example, if we envision the role of the carrier to be one of sitting in a harbor providing combat air patrol (CAP) then we don’t need a tanker at all, or no more than a small, simple tanker for overhead recovery tanking, as a safety measure.  On the other hand, if we envision the carrier conducting 10,000 mile standoff strikes then we need a mammoth mission tanker and some much longer ranged strike aircraft!  

So, what is the role of the carrier?  I’ve answered this before in both posts (see, “AircraftCarrier – What Future”) and comments but it clearly needs repeating so let’s have at it, again, and see what it tells us about tankers.

Historically, the carrier has been a strike platform both for anti-surface and land attack.  Early in WWII, carriers would dart in from a long ways off, under cover of darkness, launch strikes, and retreat before an effective counterattack could be mounted.  Later in the war, when proper carrier groups could be assembled, carriers were a bit more willing to stake out a location and stand and conduct strikes secure in the belief that they had sufficient combat power to deal with any counterattack.

Today, we talk about anti-access/area denial (A2/AD) zones that extend a thousand miles or more from an enemy’s territory.  These zones are established by the range of the weapons that can be brought to bear on any intruder – weapons such as mines, aircraft, land based anti-ship missiles, short range ballistic missiles, air launched anti-ship cruise missiles, submarines, and surface ships.  Compounding the problem for an attacking carrier group is the presence of sophisticated surface to air missile defense systems guarding high value bases and targets – systems with radars that can see and strike aircraft for hundreds of miles around.  Add to this fast, long ranged defensive aircraft armed with long range air to air missiles and it is almost taken as a given that manned aircraft cannot successfully penetrate and attack a land target defended by a peer enemy.

Increasingly, long range, penetrating strike is a mission given to cruise missiles.  That being the case, what role does the carrier serve?  Well, the cruise missiles (Tomahawks, at the moment) are mounted on Burkes and submarines.  Burkes need to get within several hundred miles of their targets.  Depending on how close the targets are to an enemy’s shoreline and how straight a course the missile will fly, the Burkes may need to penetrate hundreds of miles into an A2/AD zone to reach their launch point.  They’ll need protection to do that.  Some of that protection can be provided by their own Aegis/Standard defense systems, of course, but that alone will not be sufficient especially if we want to heavily load the VLS cells with cruise missiles rather than surface to air missiles.  Thus, the ideal escort for the cruise missile shooting Burkes is a carrier.  The carrier provides airborne protection for hundreds of miles in every direction and provides an added layer of protection to the Aegis/Standard missile defense.  Carrier aircraft also substantially decrease the likelihood of an enemy’s sensor platforms finding and targeting the carrier/Burke force.

Thus, the carrier becomes the escort for the Burkes instead of the other way around.  Or, to be more accurate, the carrier and Burkes mutually escort each other with the Burkes providing the group’s striking power.

Cruise missile shooting submarines are fine on their own.  Their inherent stealth makes them an ideal Tomahawk shooting platform and negates the need for a close escort.  Even here, though, we see another mission for the carrier – to hunt and kill the enemy’s anti-submarine forces, both surface ship and airborne.  If the carrier can relieve the pressure on the submarines, the subs can be more effective in the cruise missile shooting role.  Note, that I’m talking about dedicated cruise missile shooting submarines – SSGN’s loaded with 150+ cruise missiles, not SSN’s loaded with 12 cruise missiles – those are an ineffective and inefficient means of cruise missile delivery.

Of course, the Air Force’s long range bombers can also launch cruise missiles, if they can survive to reach their launch points.  Again, the carrier air wing can provide the local air superiority needed to clear transit lanes and safe launch points for bombers.

So, how does all this relate back to the subject of tankers? 

Understanding what the role of the carrier is, we see that the carrier does not, and indeed should not, have the role of deep penetrating, land attack strike against a peer enemy.  The job of the carrier and its aircraft is to secure local (though a very large “local”) air control for the purpose of escort.  Tankers are needed to facilitate that but not long range, stealthy, penetrating, high capacity tankers.  All we need is a medium capability and capacity tanker to support the far flung air superiority aircraft.  A fair amount of speed in the tanker would be helpful to get from one location to the next in an expeditious manner.  Other than that, the tanker would be a plain, non-descript airframe.  Conceptually, a higher speed S-3 Viking would do just fine.

Carriers and tankers are intimately related and yet we persist in discussing them in isolation.  When we discuss tankers we must do so with a clear understanding of the role of the carrier.  Of course, the role of the carrier comes from having a geopolitical strategy and the associated military strategy – one of my favorite, overarching themes.  When we lack a clear strategy we fall into a pattern of haphazard acquisitions, hoping that something we buy may prove useful in the future instead of purpose designing and acquiring assets that we know will support our strategy.

We should also note that as the A2/AD threat is neutralized and the operational distances are greatly reduced, the carrier can revert to its traditional strike role but, by definition, this will involve much shorter distances and require only a medium endurance and medium capacity tanker – just what we described for supporting the carrier’s air superiority fighters.

Navy Issues Tanker RFP

The Navy has issued a draft Request For Proposals (RFP) to industry for the planned carrier based unmanned aerial tanker, the MQ-25A Stingray, and the RFP has some interesting points and aspects to it.

First, the RFP has only two key performance parameters (KPP) and both are generic to the point of useless.  They are:

1. Carrier compatibility – the aircraft must be able to operate from a carrier and use existing catapult and recovery systems.  Duh.
2. Mission tanking – the aircraft must be capable of aerial tanking.  Again, duh.

The Navy believes this will provide greater flexibility to industry and, ultimately, to the Navy when it comes to the design of the aircraft.  Personally, I think this approach is wrong.  I think performance parameters need to be specified – speed, range, endurance, reliability, fuel capacity, etc.  Without those specs, there’s no guarantee that you’ll wind up with an aircraft that can do the job.  Frankly, this is just the Navy passing design responsibility off to industry in an attempt to avoid accountability if the program tanks (no pun intended).

On the plus side, the Navy is indicating that development should be minimized by using nothing but existing technology.

“…the new airframe effort is less about developing new tech and more about mixing and matching existing systems to make unmanned tanking a reality on the carrier.” (1)

If the Navy can actually hold to this intent, this is a monumental leap forward in common sense acquisition practice.  There is nothing about aerial refueling that requires the development of new technology.  If the Navy can hold to this intent, the resulting costs and timeline should be quite reasonable.  Unfortunately, the Navy has a very hard time resisting gold plating programs after they’ve started.  It will be interesting to see whether they can restrain themselves.

On a related note, if the Navy can actually hold to this intent, it will make an interesting contrast to the Air Force’s tanker program (admittedly, the two programs are vastly different in scope and mission) which has been a dismal failure and this program could actually become an example for how to do acquisition.  As I said, we’ll take a wait and see approach.

I’m extremely ambivalent about an unmanned tanker.  Most of the claims for it are suspect or false. 

• It won’t reduce manning much, if at all.  For every pilot removed from the cockpit, one has to take their place at a controller of some sort.

• It offers no greater endurance because its endurance will be limited by the size of the fuel tanks it will carry.  Once the tanks are empty, the aircraft will have to return to the carrier just like a manned tanker would.

• It offers no cost savings.  An aircraft is an aircraft.  If you want a plane that can travel x miles, at y speed it’s going to cost the same whether there’s a seat in it or not.  In fact, when the additional shipboard control stations are factored into the cost, it will probably be more expensive.

• There will be inevitable in-flight aircraft failures, as with any aircraft, and without a crew to deal with it and attempt to remedy it, many aircraft may be forced to abort their missions.

• UAVs have a solid historical record of crashing with some regularity.  The data on this is quite clear.  While losing a UAV is no big deal, losing a tanker affects many aircraft and missions.

Honestly, I don’t really see any concrete advantage to an unmanned tanker.  The only “advantage” is that the Navy gains experience in operating unmanned aircraft in preparation for the time when they try to operate unmanned combat aircraft and, to be honest, this alone may be sufficient justification for the unmanned tanker.

Overall, I like the start to this program.  I’m quite pleased that the Navy is going to at least attempt to produce an aircraft using nothing but existing technology for a routine mission.  If they can hold to the intent, it will be a major accomplishment and could set a pattern for future acquisitions.

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(1)USNI News website, “Navy Issues New MQ-25A Stingray Draft RFP to Industry Ahead of Final RFP in the Fall”, Sam LaGrone, 20-Jul-2017,

https://news.usni.org/2017/07/20/navy-issues-new-mq-25a-stingray-draft-rfp-industry-ahead-final-rfp-fall