In Europe, NATO once again faces a threat from Russian ground forces, postured to the East. Operations in Ukraine have conclusively demonstrated the willingness and ability of the Russian government to use force in pursuit of its foreign policy goals, echoing earlier operations in Georgia, Syria, Moldova, and Chechnya. Russian operations have also been characterized by a willingness to exploit “gray zone” operations in an attempt to remain below an escalation threshold that might result in a Western military response, or any significant nonmilitary response. Both NATO and Russian strategists realize that any European conflict can be tilted by airpower, and Russian efforts to neutralize a (presumed) NATO airpower advantage should be expected even before any overt breakout of hostilities.

The resurgent Russian threat differs from the older Soviet threat. Today, Russia has the ability to threaten airbases, ports, and supply points with precision missiles in a way the Soviets did not. In response, the United States is considering distributed operations – spreading forces in small detachments over a wide area – thereby reducing reliance on easily attacked point targets. For the air component, this means distributing combat power away from large airbases and towards small combat formations that utilize the dense airfield structure in Western Europe for short-duration refuel-and-rearm efforts that could occur inside the Russian targeting cycle. Russian magazine depths for precision missiles are insufficient to target every long runway in Europe. In order to recognize the full potential of distributed operations, the Air Force should relook at airlift provided by aircraft that are much smaller than the C-130 or C-17, and can operate from shorter and rougher airfields, or no airfield at all. In short, we need to reconstitute our small tactical airlifters.

The Air Force has insufficient funding and inadequate time for a new-development aircraft program. The C-27J program was the last gasp of the small airlifter, killed by the Budget Control Act of 2011. As with so many sequester-imposed cuts, this has left the Air Force with long-term damage to its warfighting mission that will be hard to resolve in today’s fiscal environment. Still, even the C-27J is too big, too expensive, and requires too much runway to support distributed forces. On the other hand, civil airlifters are small and agile enough to deliver critical supplies to support distributed operations. Too bad the Air Force doesn’t have any.

Figure 1: A U.S. Air Force Caribou over Vietnam 1970 or 71, taken from the back of another Caribou. (U.S. Air Force photo by Tech Sgt. David Sommers)

A Look Back

The C-7, as the USAF was later to designate the Caribou, possessed unique qualities which set it apart from the C-123, the C-130, and other regular transport aircraft in its ability to use shorter unimproved airstrips in forward battle areas.

The majority of the [US] Army’s 144 Caribous were in Vietnam, servicing those airfields–about 40 in number– from which C-123s and C-130s could not operate. Like the Australian C-7s, they were the lifeline to Special Forces outposts and remote USAID projects.

–Project CHECO Report: The RAAF in SEA

The United States faced an airlift conundrum in Vietnam. American, allied, and South Vietnamese forces were often spread out among bases with poor airfields that could not support larger airlifters like the C-123 or C-130. The Air Force’s tactical airlift at the time (much of which was owned by Tactical Air Command and not the Military Air Transport Service) consisted largely of C-130 and C-123, which were too big and heavy for many austere bases. But there were other options in 1962, because the Army and the Air Force each had a robust, short-field airlift capability, using civil designs.

The Army operated almost a thousand DeHavilland DHC-2 Beavers as the U-6 and another 184 DHC-3 Otters as the U-1A; the Air Force, CIA, and Army operated the Helio Super Courier as the U-10, and the Army operated another 159 DHC-4 Caribous, later designated C-7A. C-7 aircraft were used extensively in Vietnam, alongside Royal Australian Air Force C-7 Caribou (referred to as the “Wallaby”), for resupply of forward bases. In 1966, the Army was forced to transfer their C-7A to the Air Force, which thereby gained a light airlifter with short takeoff and landing capabilities. In 1967, the C-7 was flying into 188 of the 300 primitive strips in Vietnam delivering ammo, building supplies, fuel, personnel, and food, which sometimes included live animals to units that lacked refrigeration. Directed by the 834th Air Division, Royal Australian Air Force, and later U.S. Air Force, the Caribou shuttled between a handful of main bases to forward operating locations, often operating in detachments as small as four aircraft.

The Caribou was an excellent plane for front line support into short rough surface landing strips. Able to land on a 700-foot field, it could take off in an even shorter distance and could carry 5,000 pounds of cargo; 32 passengers, 28 fully equipped combat troops, or 20 litter patients. Compared to the Army’s performance of 1966, Air Force C-7s in 1967 flew 20 percent more hours and 26 percent more sorties and the planes carried a third more passengers and 10 percent more cargo. The flyers had squeezed an additional squadron’s payload out of a slightly smaller number of airplanes than the Army had operated…

– Project CHECO Report: Forward Airfields for Tactical Airlift in SEA

Southeast Asian airfields were categorized into three classes, from austere day-only fields to full-up, all-weather bases. The C-130 had the most restrictive requirements, the C-7 the fewest, and the C-123 somewhere in between. Airfield condition was an issue – a C-130 tore up dirt, semi-prepared, or steel-mat runways almost 10 times faster than a C-7. C-7s could land on gravel, cinders, and sod, none of which were authorized for the larger aircraft. The worse the airfield condition, the more likely that the C-130 and C-123 wouldn’t be able to service it. Despite its success, the C-7 Caribou left the Air Force inventory in 1985. It was replaced in Europe by the C-23 Sherpa, which itself succumbed to the drawdown in 1990, leaving the Air Force without a small airlifter. Arguably it hasn’t had a need for one. But it might.

Distributed Operations in Europe

Europe has a much more robust airfield infrastructure than Vietnam, but the vast majority of its airfields are vulnerable to air attack. Defense planners envision conditions under which a Russian missile attack is a real possibility and combat airpower must be shuttled to civil fields to remain in operation. So must the logistical support necessary to rearm, refuel, and to some extent maintain the aircraft. Unlike in Vietnam, the United States must not only fly supplies into European airfields, but also move supplies out of airfields that are subject to attack. It seems likely that NATO forces will need to distribute their logistics, resulting in three levels of “supply dump” – major fixed facilities, intermediate depots, and the final, distributed supply dumps to support forces at the tip of the spear. Our existing large airlifters will be hard-pressed to service the intermediate depots, much less keep the sharp end supplied and manned.

There will inevitably be heavy lift requirements for large items that are needed to open a fighter operating location. An example of a large item is the Air Force “MJ-1” weapons loader, commonly called a “jammer,” that requires a C-130 or a truck. But heavy equipment aside, distributed operations will depend on critical components, consumable parts, and specialized maintenance personnel that are easily relocated by smaller cargo aircraft. No logistician can perfectly predict where and when an aircraft will shred a tire or break a part. Frontloading every possible consumable item or specialized maintainer to each distributed location is infeasible. The ability to responsively move small packages quickly is a critical enabler and also offers a way to extract irreplaceable personnel (including casualties) and residual materiel.

Figure 2: An Air Force MJ-1 “jammer” prepares to move a BLU-109 warhead during Operation Allied Force. The MJ-1 has been in continuous use as an ordnance loader since the 1950s and is too large and heavy for a Twin Otter. (U.S. Air Force photo)

Distributed combat operations will degrade efficiency – it will be much harder to optimize the application of combat airpower when assets are strung out all over the continent. But it will also be much harder to target the airbases that are airpower’s critical vulnerability, because there are so many suitable civil fields. It will be difficult for Russian forces to catch aircraft on the ground if they are only on the ground for short periods, and if NATO combat aircraft don’t return to predictable locations. In order for this concept to work, the U.S. military will have to match agile combat operations with agile logistics, to position and move fuel, weapons, parts, aircrew, and support personnel. To make the Joint situation worse, the Army also envisions that they will likewise have to operate in distributed packets, adding another large logistical demand to the mix. The authors think it unlikely that the Army rotary wing will be able to handle their own demands, much less help out NATO air forces. That goes double for NATO, which has become accustomed to unimpeded land transport and which has a shortage of tactical airlift.

The Civil Option

What if the Air Force had airlift that could operate out of fields too short, soft, or damaged to support its existing airlifters? There are three attributes that are critical for the small airlifter; cargo capacity, rough-field utility, and short takeoff and landing (STOL) performance. These factors are a tradeoff, given that the smaller cargo aircraft trade away the first attribute for the latter two. There has long been a demand for this category of aircraft; De Havilland Canada built a business servicing this market niche for decades. Today, there are still STOL aircraft in production overseas in India, Germany, Poland, and Indonesia.

Figure 3: Already in service: members of the Golden Knights depart their UV-18C, a 400-series Twin Otter (U.S. Army photo)

“There is only one STOL option built in North America, but it’s at the front of the pack for STOL performance; the new 400-series Twin Otters, are modern glass-cockpit aircraft that can be equipped with rough-field landing gear, skis, or floats. The Twin Otter is a wildly successful design, having operated worldwide from Norway to Indonesia to the South Pole, and endless dirt, brush, beach, ice, and sod airfields. The useful cargo load over short (100 nautical mile) distances is over 4,000 pounds – enough weapons to fully rearm an F-22 with eight air-to-air missiles, 480 rounds of ammunition, plus chaff and flares. Its STOL performance is legendary and notably better than the Twin Otter’s closest competitors. It’s economical, burning 267 pounds of fuel for a 29-minute, 55 nautical mile leg, and has a unit cost of $7 million.

With a 2,400-pound payload with full fuel, the Twin Otter is not nearly a C-130J, which can lift up to 43,700 pounds with a full load of fuel. But today’s C-130J is not the Vietnam-era C-130B, which maxed out at 135,000 pounds and weighed 70,000 pounds empty. Today’s C-130J maxes out at 175,000 pounds (wartime weight) with a wingspan of 132 feet and a minimum runway width of 80 feet. The C-130 has gained substantial weight since Vietnam, weighing in at 88,000 pounds empty. That massive hauling capacity and high gross weight is reserved for high-strength airfields; the maximum weight for “marginal strength airfields” for the C-130J is 110,000 pounds, leaving 22,000 pounds for fuel and cargo. Fuel requirements cut down the effective payload down to about 12,000 pounds for a 100 nautical mile flight and return.

This is where the Twin Otter starts to look attractive. Really attractive. Assuming a 100 nautical mile round trip, it burns 408 pounds of fuel each way and hauls 3,100 pounds of cargo while maintaining a 30 minute fuel reserve. It can use short runways with low bearing strength; see the Aircraft Classification Number (ACN) in Figure 4 below, where the lower the number the better. Its wingspan is 65 feet; International Civil Aviation Organization and Federal Aviation Administration regulations limit it to a minimum airfield width of 60 feet – or it can land on water, if equipped with floats. And it costs a lot less. If one Twin Otter’s cargo capacity seems paltry compared to a C-130, compare instead the capacity of the dozen Twin Otters that can be purchased for the cost of a single C-130J.

Figure 4: Comparative mission data, DHC-6-400 v. stretched C-130J.( Author’s work)

Figure 5: Royal Canadian Air Force CC-138 Twin Otters on a dry lakebed (Royal Canadian Air Force photo)

The C-130J is immeasurably superior to the Twin Otter for hauling cargo over intermediate ranges, even to airfields that are short and in poor condition. But there is a minimum length and runway capacity that the C-130 cannot go below, and the Twin Otter can. The Twin Otter is never going to haul earthmoving equipment, combat vehicles, or Ranger companies. But it will haul a militarily useful load where the C-130 cannot go and can operate from roads, cleared fields, and rivers and reservoirs (if float equipped).

Complicating Targeting

One of the assumptions that underpins the need for distributed operations is the expectation that our airfields will come under effective attack. There’s no sense putting all of our eggs in one basket, and aircraft destroyed on the ground are aircraft destroyed. It’s difficult to destroy a runway, but precision munitions can damage one. The fact that airfields are solidly made helps – runways are not destroyed but rather cut into segments too small to utilize. But “too small to utilize” is entirely aircraft-dependent. Three hits can cut an 8,000 foot runway into 2,000 foot segments, all too short to launch a loaded C-130. The same runway has to be hit seven times to cut it into 1,000 foot strips too short for a Twin Otter, and even then a Twin Otter could still operate off the taxiways, or nearby roadways, or the turf next to the runway.

Figure 6: Wearing full chemical protection gear, members of the 52nd Civil Engineering Squadron examine a damaged runway from the top hatch of a Cadillac Gage Commando Ranger vehicle during Exercise SALTY DEMO 1985. Repairing this crater is harder, takes longer, and deteriorates faster if the runway has to support C-130 operations. (U.S. Air Force photo)

Eastern Europe lacks the general aviation infrastructure taken for granted in countries to the west. But one of the unique features not found in the west are the old Aeroflot-built agricultural airfields. Built to support the operations of AN-2 crop-dusters, they are uniformly 400 meters long and 20 meters wide, surfaced in concrete or asphalt. Most are abandoned, but intact, while a few are active and some have been mined for material or used as foundations for new buildings. They are scattered throughout the former Warsaw Pact. Lithuania alone has over 100 of these small airstrips. They are too short for a C-130, but usable by a Twin Otter at maximum weight.

To illustrate the airfield demands of the C-130 and Twin Otter, the authors picked a randomly selected civil airfield in eastern Europe with 10,600 feet of runway, plus a relatively short 3,300 foot parallel taxiway (see Figures 6 and 7). The airfield in question is normally suitable for C-130s and fighters. Five well-placed hits later, the runway can’t accommodate either. Twin Otters can still use the parking ramp, the taxiway, the cargo ramp, or the grass alongside the runway. Within 10 miles, there are two four-lane highways, an agricultural strip, plus two rivers and a reservoir, to say nothing about plain old cleared fields. Within 20 miles, another four-lane highway, two more agricultural strips, one abandoned ex-Soviet airbase, another reservoir, and a 3,800 foot civil field with an aero club. The C-130 may be able to use the airbase, civil field, and parts of the highway, but the Otter can use more. To deny the Twin Otter a landing field, those four hits on one runway have just become hundreds on the runway, taxiways, parking apron, infield, the airfield surroundings, and neighboring airfields and roads. The water features? Immune to attack. Russian attacks can deny the airfield to fighters and C-130s, but they cannot prevent our light airlifter from getting into or out of the area by hitting landing surfaces.

Figure 7: Airfield X – C-130. The red bars represent the 2,500 foot takeoff distance in Figure 4 and were laid on the parking ramp, runway, taxiway, overruns, and displaced threshold. Six hits (marked by yellow circles) are enough to prevent a lightly loaded C-130 from taking off.

Figure 8: Airfield X – Twin Otter. The yellow bars represent the 1,200 foot takeoff distance in Figure 4 and were laid on the parking ramp, runway, taxiway, overruns, displaced threshold, cargo pad, crossing taxiway, and grass infield. We took into account obstacles and roads. The bars, all 44 of them, are illustrative – had we laid them edge to edge, including diagonals, the airfield would be a solid yellow blob with more than 100 bars. The six hits on the map are insignificant. The highway to the north provides additional takeoff and landing opportunities.

Taking Distributed Ops Seriously

This article isn’t intended to substitute a detailed analysis done by air logistics professionals. If NATO is going to consider distributed operations in Europe, we need to consider them seriously. That means we need a more detailed look at the logistics requirements of distributed operations and the ability of current airlifters to service them in a difficult environment. Logisticians cannot rely on long-haul ground transport for timely movement of crews and weapons – it’s bad enough that NATO will likely have to rely on ground transport for fueling a very thirsty fighter force. The Russians are aware of this and can be expected to make ground transportation as difficult as possible. We have a case study that shows how to air supply dispersed locations – the story of Vietnam is one of shifting bases, changing requirements, and use of distributed forces. In Vietnam, the enemy was often foliage, water, and terrain, but was a difficult and unforgiving adversary for all of that.

Air transport is only as viable as the aircraft that fly the routes and the airfields that make up the network. Europe has the airfields to sustain a robust air effort, right up to the point where Russian missiles start hitting them. After that point, the kind of aircraft we have matter a lot more if they can fly into short, damaged, or makeshift airfields. The Russians simply cannot deliver the weight of precision ordnance necessary to prevent Twin Otter operations across the theater – there aren’t that many missiles in their inventory. Given the huge cost disparity between the C-130 and the Twin Otter, it would seem that a relatively paltry investment in new small airlift aircraft could pay big dividends. It also offsets requirements for redundant personnel and equipment by reducing what we have to send forward in the initial dispersal by providing a more dynamic re-supply capability that can adjust for local conditions and operational requirements. Just having this kind of aircraft in the inventory will greatly complicate the targeting picture for Russian forces and add to the weight of NATO’s deterrent.

Col. Mike “Starbaby” Pietrucha was an instructor electronic warfare officer in the F-4G Wild Weasel and the F-15E Strike Eagle, amassing 156 combat missions over 10 combat deployments. As an irregular warfare operations officer, Pietrucha has two additional combat deployments in the company of U.S. Army infantry, combat engineer, and military police units in Iraq and Afghanistan. He is currently assigned to Air Combat Command.

Lt. Col. Jeremy “Maestro” Renken is an instructor pilot and former squadron commander in the F-15E Strike Eagle, credited with over 200 combat missions in five combat deployments. He is a graduate of the U.S. Air Force Weapons Instructor Course and is currently an Air Force fellow assigned to Air Combat Command. The views expressed are those of the authors and do not necessarily reflect the official policy or position of the Department of the Air Force or the U.S. government.

Image: Last of the Caribou: a DHC-4T Turbo Caribou cargo plane (one of only three converted) of Flightworks Aviation approaches a remote Special Operations outpost in Uruzgan, Afghanistan, Feb. 27, 2013. (U.S. Army photo by Sgt. Jessi Ann McCormick)