Carrier Drone Debate

Was it wise or foolish for U.S. Navy to choose a refueling drone as a warplane?

The vision was spectacular: A drone that could take off and land on an aircraft carrier, flying combat missions from day one of a battle; firing weapons; collecting intelligence, surveillance and reconnaissance; flying farther and lingering longer than any manned fighter in the U.S. Navy’s arsenal; and evading modern-day air defenses with stealth technology.

But the reality now looks mundane to those who favored this vision. The Navy announced in February that its forthcoming carrier-based drone will be a  tanker for aerial refueling of traditionally piloted fighter jets, with some intelligence, surveillance and reconnaissance equipment aboard.

Critics inside and outside of the Pentagon are now speaking out about the Navy’s decision. They suggest it puts the service out of sync with the increasingly sophisticated weapons abroad, including vastly improved air defenses and a Chinese antiship missile that could force U.S. aircraft carrier groups to stay farther away from their intelligence or strike targets. For its part, the Navy says it hasn’t given up on fielding unmanned combat planes at some point, and it maintains that this was the right budget choice for the state of unmanned technology. The debate shows no signs of abating, with a report due in 2017 from the Government Accountability Office, and the Navy in the throes of planning the unmanned tanker acquisition.

High expectations

During the Unmanned Carrier-Launched Airborne Surveillance and Strike, or UCLASS, program, the carrier drone concept came with high expectations. A demonstration version built for a UCLASS predecessor program had aced automated aircraft carrier landing and takeoff tests. That plane, a Northrop Grumman-built X-47B, nailed all seven of its autonomous carrier landings in 2013. Hooking the third arresting wire out of four available for an aircraft carrier landing is the goal for U.S. Navy pilots — one of the most difficult tasks that any human pilot can accomplish — and the X-47B not only hit the three wire, but touched down within seven centimeters of its target with every landing.

Besides its autonomous carrier takeoff and landing performances, the stealthy X-47B also demonstrated autonomous mid-flight refueling, taking on 1,815 kilograms of fuel from a Boeing 707 Omega tanker in 2015.

The idea behind UCLASS was for the Navy to improve its intelligence, surveillance and reconnaissance capabilities and its ability to fight battles where the enemy has integrated air defenses with dense layers of overlapping sensors, airplanes and missiles, including anti-ship missiles. The X-47B was designed without a tail in a strategy to reduce its radar signature, so that a successor combat or ISR version could penetrate hostile airspace. Without a human pilot aboard the plane, engineers could design the plane to stay airborne much longer, enhancing its range and the ability of the Navy to strike distant targets or gather intelligence with cameras and eavesdropping equipment.

Among those worried about the Navy’s decision to abandon that role for the X-47B’s successor is retired Adm. Gary Roughead, the Navy’s chief of naval operations from 2007 to 2011 and now a Northrop Grumman board member.

“One of the objectives of any potential adversary is to keep our air power as far away as possible,” Roughead says. “The last decade or so, we’ve really been able to operate unfettered in the skies where we’re conducting combat operations. I don’t think that’s going to be the case in the decade, decade-plus going ahead.”

Roughead would like to see the Navy make it a priority to incorporate unmanned, long-range, refuelable, strike-capable airplanes into its carrier air wings. As matters stand, the Navy plans to hold off on unmanned combat-ISR planes, probably for at least five years and the targeted time frame for the tankers will have them fielded in 2023 or 2024.

For aircraft carriers, one threat that could push them farther away from the enemy is the Chinese DF-21D anti-ship ballistic missile, dubbed a “carrier killer” in an analysis of threats to U.S. ships. It is a hypersonic weapon with a 1,850-kilometer range that could knock out a carrier in one hit. That compares to the unrefueled combat radius of about 930 kilometers for the F/A-18 E/F Super Hornet, and to about 1,110 kilometers for the planned F-35C Joint Strike Fighter. The X-47B demonstrator has a range of 3,890 kilometers.

As envisioned by one proponent, Jerry Hendrix — a retired Navy captain and senior fellow at the Center for a New American Security, a Washington, D.C., think tank — an unmanned airplane developed along the lines of the X-47B would have an unrefueled combat radius of more than 2,780 kilometers, the ability to fly for 14 hours without mid-air refueling or 50 hours with it, the capacity to carry 1,815 to 2,720 kilograms of bombs, stealthy radar-avoiding characteristics, and the ability to provide ISR coverage for the carrier and its escort ships.

The range and loiter advantages of drones give them a big advantage over conventional planes, says retired Lt. Gen. David Deptula, dean of the Mitchell Institute for Aerospace Studies in Arlington, Virginia, and the Air Force’s  ISR chief from 2006 to 2010.

“It’s the persistence that allows time to observe, evaluate, act really quickly or take all the time that’s necessary to be sure of a particular action, but that also translates in the case of the Navy into range, which will be standoff, so you can still have an effect much farther away from the launch and recovery deck than with a manned aircraft,” Deptula says.

UCLASS-type drones also could boost the effectiveness of manned planes when they are flying in contested airspace. The drones could complement the planned B-21 Long Range Strike Bomber by gathering target data in contested airspace that the bomber would use when it arrives, says Keven Gambold, head of Unmanned Experts, a consulting firm based in Colorado, and a former commander of a Predator drone squadron.

The switch

Officially, the Navy until February was planning to spend more than $3 billion on UCLASS development through fiscal year 2022. But in the Department of Defense’s fiscal year 2017 budget proposal, the Navy switched gears away from UCLASS to a carrier-based refueling drone with some ISR capabilities. Initially called CBARS, for Carrier Based Aerial Refueling System, and then MQ-25A, the tanker drone will cost more than $2 billion through fiscal year 2021, or $1 billion less than UCLASS, according to a Navy spokesman.

The budget reveal was a surprise for outsiders tracking the UCLASS development, and even for the Congressional committees involved with defense budget planning, one congressional aide said.

UCLASS fans see the switch as a mistake.

“It’s a bit like saying we designed a Formula 1 race car, and it’s pretty much good to go, so let’s buy a scooter, and we can always go back to the Formula 1,” says Gambold, the unmanned aircraft consultant. “They have a successful program, it looks like it’s going all the way, it looks like it literally is world-beating, and they turn it into a tanker.”

Deptula counts himself as a skeptic too. “Frankly, the logic of going from the UCLASS design as an ISR strike aircraft to an unmanned refueler is pretty thin,” Deptula says. “What is ultimately the benefit of this if you don’t have ISR and you don’t have strike, why are you doing this? To say that you’re just going to offset some F-18s that you otherwise would have to use for buddy refueling, that’s pretty soft logic for incorporating an entire new system into the panoply of carrier assets.”

Another issue is the timeline, says Roughead, the former chief of naval operations. Because it takes eight to 10 years to develop an airplane and field it, if long-range strike/stealth is a priority today, going with a tanker/ISR plane just pushes the strike/stealth option — and its eight-to-10-year development — even further into the future.

Navy perspective

The Navy says it had to choose the tanker-ISR path because moving forward with plans to develop a stealthy strike airplane, without the funding or current technology to make it possible, was going to lead to cancellation of the carrier-based drone program.

Otherwise, the Pentagon’s budget managers tell the Navy, “we’re going to stop funding it, and we’ll come back when you guys have your stuff together,” says a Navy expert within the Department of Defense who asked not to be identified. Stealth capabilities are extremely expensive, and strike missions would require extensive advances in autonomous flight and machine learning technologies. “They could not deliver, in the budget and the time line, all the requirements that they wanted. It just wasn’t possible.”

The chief of naval operations, Admiral John Richardson, speaking at a conference in March, says his goal with the tanker-ISR plan is for the Navy to begin operating an unmanned plane, with a legitimate mission, from carriers so the Navy can learn about how to integrate drones into its carrier air forces. And when new technology is made available, it can be incorporated into the unmanned plane’s design.

The Navy plans to work with the four bidders on the UCLASS preliminary design — Lockheed Martin, General Atomics, Boeing and Northrop Grumman — to gather information about their technology that might apply to the MQ-25A. The Navy expects to issue that request for proposals, then the information gathered from the contractors will help shape its final design requirements, which are expected sometime after Oct. 1. The Navy would field the plane on aircraft carriers as early as 2023, but more likely after 2024.

For five years, congressional leaders have been pushing the Navy to equip the forthcoming carrier-based planes with strike, stealth and ISR capabilities to penetrate highly contested airspace. Even before switching to the tanker option, the Navy has pushed back with lower-cost plans for  drones that would conduct mostly surveillance missions in less-contested air space, with the goal of getting the planes fielded quickly and maximizing flight time endurance.

Congress is still insistent on the strike capability, and for operating in highly contested airspace in its report on the 2017 defense authorization.

The House Armed Services Committee characterizes the tanker option as a “slight variation” on earlier UCLASS requirements — a characterization that UCLASS advocates would argue withand notes that planned drone requirements still include ISR and strike, though now the capabilities list includes “future precision strike.” The committee also expresses concern that the Navy will be leaving strike capabilities out of its request for proposals for the tanker design and “may be excluding a critical capability and precluding future growth in a platform that will likely be integrated into the carrier air wing for the next 30 years.”

The bill includes a directive to the U.S. Comptroller General, who directs the Government Accountability Office, to report on the Navy carrier drone program’s progress by March 2017.

While strike and stealth won’t be part of the initial design requirements for MQ-25A, they will still be available as options that the Navy could add at some point after the test flights begin, maybe in about five years, says the Department of Defense naval expert.

The notion that the X-47B — the demonstrator drone with the impressive autonomous carrier landings — could be simply turned into a strike-stealth airplane is misguided, says the Department of Defense expert. The plane was a prototype, and it proved the concepts it was designed for — the autonomous refueling and takeoffs/landings. But it also had flight systems that are now at least 10 years old, which the Navy wouldn’t use for a future aircraft, and it was designed as a test bed, making it inherently inefficient for other specific requirements.

By taking an approach that will allow for flexibility as new technology is developed, the Navy is also keeping options open that aren’t yet known. Just as when smartphones were introduced and society at first didn’t know how they would be used, new technologies should give carrier-based drones novel capabilities, not just allow the drones to perform the same functions of manned aircraft, the Defense Department expert says. For example, technology advances may push ahead the concept of unmanned aircraft operating as surrogates deployed from the wings of larger aircraft, such as a P-3 Orion or C-130 Hercules, or in swarms of four or five wingmen controlled from an F-35.

Related Topics

Military Aircraft

About Keith Button

Keith has written for C4ISR Journal and Hedge Fund Alert, where he broke news of the 2007 Bear Stearns hedge fund blowup that kicked off the global credit crisis. He is based in New York.

It’s a bit like saying, ‘We designed a Formula 1 race car, and it’s pretty much good to go, so let’s buy a scooter, and we can always go back to the Formula 1.’

Consultant Keven Gambold on the contention that a naval unmanned combat and intelligence plane could be revived if the need arises.

Devolving drone requirement

The U.S. Navy’s controversial decision to shelve plans to develop the drone equivalent of a carrier-based F/A-18 in favor of an unmanned refueling plan did not spring from nowhere. The seeds of the decision are visible in years of back and forth over just how ambitious the requirements for the plane should be. Here is a timeline:

FEBRUARY 2006: The Pentagon’s 2006 Quadrennial Defense Review proposes a long-range, carrier-based drone capable of being air-refueled. The Navy Unmanned Combat Air System, or N-UCAS, must have “persistent, penetrating surveillance, and penetrating strike capability in high threat areas” and “suppress enemy air defenses.” The Navy starts the Unmanned Combat Air System Demonstration, UCAS-D, program to demonstrate operating an unmanned airplane from a carrier.

AUGUST 2007: The Navy awards Northrop Grumman a six-year, $635.8 million contract to build two X-47B demonstrators to show the ability of a tailless, fighter-sized drone to land on and launch autonomously from aircraft carriers. The demonstrators are to be built under the Unmanned Combat Air System Demonstration program.

JUNE 2011: The Pentagon’s Joint Requirements Oversight Council, JROC, approves a program called UCLASS, for Unmanned Carrier-Launched Airborne Surveillance and Strike System, to develop “a persistent, survivable carrier-based Intelligence, Surveillance, and Reconnaissance and precision strike asset.”

DECEMBER 2012: The JROC alters the requirements for UCLASS to favor intelligence capabilities in “permissive airspace” in what is widely interpreted as a cost-cutting decision.

JULY 2013: Off the coast of Virginia, an X-47B makes the first autonomous landing on a carrier, the USS George H.W. Bush.

AUGUST 2013: Northrop Grumman, Lockheed Martin, General Atomics Aeronautical Systems and Boeing each receive a $15-million contract for competing preliminary designs for a UCLASS plane.

SEPTEMBER 2013: The Government Accountability Office reports that the Navy’s scaling back of the UCLASS requirements is a step toward affordability and that the GAO disagrees with the Navy’s plan to develop and field UCLASS before a Pentagon Milestone B review establishes a baseline for cost, schedule and performance. The Navy disagrees, saying it is complying with acquisition regulations. Congress responds by limiting the number of UCLASS drones that the Department of Defense can acquire before receiving Milestone B approval.

DECEMBER 2013: The Fiscal 2014 National Defense Authorization Act passed by Congress orders the Government Accountability Office to review the UCLASS program annually.

APRIL 2014: The Navy issues a draft request for proposals for UCLASS. The document is classified, but according to the Government Accountability Office, it emphasizes affordability and quick fielding, while de-emphasizing operations in “highly contested environments.”

MAY 2014: The Navy completes the preliminary design review of the UCLASS proposals submitted by the four contractors.

MARCH 2015: Softening of the UCLASS requirements does not sit well with Sen. John McCain, R-Arizona, chairman of the Senate Armed Services Committee. He writes to Defense Secretary Ashton Carter to say that a carrier-based drone should be capable of strike and ISR missions in “medium- to high-level threat environments” while carrying 1,800 kilograms of weapons and flying several times longer and farther, without refueling, than conventional carrier aircraft.

APRIL 2015: An X-47B demonstrator conducts the first autonomous aerial refueling of an unmanned aircraft.

MAY 2015: The Government Accountability Office reports that questions about the UCLASS mission and capabilities led to delays. GAO notes that the UCLASS program is expected to field its first drone no earlier than fiscal 2022, or about two years later than originally planned. The report cautions that the Navy might have to repeat the entire preliminary design process if it were to restore requirements for strike, increased payload or fuel capacity, or operating in highly contested airspace, as urged by Congress.

FEBRUARY 2016: The Navy announces the switch from UCLASS to CBARS, or Carrier Based Aerial Refueling System, a tanker for refueling other aircraft, in its proposed budget for fiscal 2017. CBARS is designated the MQ-25A


  • CBARS Carrier Based Aerial Refueling System
  • JROC Joint Requirements Oversight Council
  • N-UCAS Navy Unmanned Combat Air System
  • UCAS-D Unmanned Combat Air System Demonstration
  • UCLASS Unmanned Carrier-Launched Airborne Surveillance and Strike System
An X-47B receives fuel from an Omega K-707 tanker in 2015. The autonomous refueling came after the stealthy X-47B aced its automated aircraft carrier landing and takeoff tests.
An X-47B receives fuel from an Omega K-707 tanker in 2015. The autonomous refueling came after the stealthy X-47B aced its automated aircraft carrier landing and takeoff tests. Credit: US Navy
A pilot in an orange suit gestures toward a boeing futuristic stealth aircraft surrounded by smoke, watched by another pilot in a yellow suit.
An artist’s rendering of Boeing’s proposed Unmanned-Carrier-Launched Airborne Surveillance and Strike System combat drone. The Navy no longer plans to build UCLASS. Credit: US Naval Institute
An x-47B demonstrator test aboard USS Theodore Roosevelt. The X-47B hooked the third wire on all its attempted autonomous carrier landings.
An x-47B demonstrator test aboard USS Theodore Roosevelt. The X-47B hooked the third wire on all its attempted autonomous carrier landings. Credit: US Navy

Carrier Drone Debate