February 4, 2016
Turning the US Navy’s next carrier-based drone into a tanker, as the service announced this week, is probably a reasonable idea. For some time, buddy-tanking F-18 Hornets has been a questionable use of other Hornets, but one  completely necessitated since 2009 by the full retirement of the Lockheed S-3 Viking. The drone-tanker also makes for a modest start. On the USNI blog yesterday, Commander Salamander called it a “Choice of Prudence,” questioning whether the hardware and software needed for autonomous combat aircraft were really ready for the hardest missions. As I have argued previously, this also allows the Navy to build operational experience with carrier-based drones before it proceeds with plans for a penetrating, stealthy, unmanned bomber. Pumping jet fuel through a drogue hose at altitude is a task that doesn’t clearly require an aircrew, and that doesn’t create a killer robot. But rather than questioning whether the carrier-based drone should first be a tanker, we might also ask why the fleet’s aerial tanker should be carrier-based. Then, we should ask what other questions are going unasked.

To extend the range of carrier-based fighter-bombers, jet fuel needs to be delivered at altitude. The US Air Force and the US Marine Corps have KC-135s, KC-10s, and KC-130s for this mission, but the land-based tankers don’t quite accompany the fleet. Fuel is thus needed from the sea, but why lift it off a carrier deck, or even from a carrier at all? Every carrier underway is accompanied by an oiler, currently of the Henry J. Kaiser class, and eventually of the John Lewis class. From that ship, fuel flows into the carrier’s tanks during an underway replenishment, and later from the carrier’s tanks to the aerial refueler’s tanks. So here’s an alternative, suggested by Commander Phil Pournelle of the Office of Net Assessment: trail the carrier group with aerial refueling seaplanes. Refueling the tanker directly from the oiler (through a hose trailing astern) skips a step, frees deck space and cycle time on the carrier, and brings more fuel to altitude faster.

Of course, it’s reasonable to ask whether the US Navy needs another full-scale developmental aircraft program right now. Frankly, it needn’t need one, because there already two plausible options.

In the mid-1950s, the Glenn L. Martin Company built 14 early production models of the P6M Seamaster, a twin-engine, jet-powered seaplane that was a bit larger than a Lockheed Martin C-130. In its bureaucratic competition with the US Air Force, the Navy had planned these as part of a nuclear-armed “Seaplane Striking Force”. The P6Ms may have made at least as much sense as aerial minelayers, a mission the USAF has long since undertaken with B-52s. Martin’s twin turboprop P5M Marlin was more successful as a program, serving in the Navy from 1952 to 1967. The Seamaster, though, had some considerable advantages—particularly its payload, akin to that of a modern Hercules. The aircraft did have a troubled development, including a fatal crash, but the basic concept has since been proven. Today, nine Beriev B-200 twin-jet seaplane water bombers fly fire-fighting missions for the Russian Emergencies Ministry. Building updated P6Ms—and with drogue hoses—would be an undertaking, but most of the design was done half a century ago.

Another candidate is already in service with an allied military. Since 2007, the 71st Squadron of the Japanese Air Force has been operating four Shinmaywa US-2 turboprop amphibious aircraft (that is, which can land on land or water) for search-and-rescue. An earlier model, the US-1, was also a submarine hunter, rather like Lockheed's S-3. In the 1960s, Shinmaywa was even overhauling the US Navy’s P5Ms. (James Simpson wrote a compact history of the business for War Is Boring last year.) For the past several years, the company has been trying to sell a squadron to the Indian Air Force for service in the Andaman Islands, but as with all things in Indian military procurement, this is taking longer than it should. Part of the attraction of the four-engined US-2 is its meaningful payload—around half that of a C-130.

There are clear limitations to this approach. Ampibiosity isn’t free: boat-like fuselages aren’t the most efficient for forward flight. Water-landing aircraft can’t undertake rough-water rescues like helicopters. In high seas, they can’t take fuel from oilers. Thus, they’re clearly not a total replacement for either rotary- or fixed-wing shipboard aircraft. But when sea conditions are reasonable, they can supplement shipboard aircraft in many missions, with greater payload at greater range. And there’s already a precedent in the sea services.

In the early 1950s, as Commander BJ Armstrong of Kings College London recently wrote in “The Answer to the Amphibious Prayer,” the USMC thought that seaplanes might offer a more dispersible alternative to large ships for assault over the beach. Seaplanes' runways can’t be cratered, and they’re not such tempting targets for cruise missiles. They can deploy from any sheltered bay or cove, as long as a tender accompanies them. If that’s not mobile enough, note how the USMC uses its land-based KC-130s in all sorts of roles: aerial tanking, transport, surveillance, and even ground attack with the Harvest Hawk combat package. With all that functionality, it’s no surprise that every shipborne Marine Expeditionary Unit is followed around the world by two KC-130s, making use of friendly landing facilities where they can. But as with USAF's tanker-transports, that's not fully expeditionary, and “expeditionary” is the highest of compliments in the Marine Corps.

The broader point is that the Navy, the Marine Corps, and many other military organizations often have unconsidered options. Seaplanes might seem like yesteryear’s technology with circumscribed possibilities, but the math for getting fuel into fighter-bombers at altitude doesn't favor aircraft designs which must fit onto ships. So as we charge forward with all the man-machine interfacing of the Third Offset, it’s worth asking what existing, proven concepts we can cost-effectively dust off.

James Hasík is a senior fellow at the Brent Scowcroft Center on International Security.

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