Published Airpower Journal - Winter 1997


Way Points


A mind stretched to a new idea never goes back to its original dimension.

--Oliver Wendell Holmes


UNINHABITED COMBAT AERIAL
VEHICLES: REMOVE THE PILOT?

ANDREW A. PROBERT

In New World Vistas, the Air Force Scientific Advisory Board recommended that the Air Force pursue development of uninhabited combat aerial vehicles (UCAV). This awkward but politically correct name refers to aircraft capable of delivering weapons without “on-board presence of pilot or aircrew.”1

UCAVs have the attention of people who develop new technology and new air-vehicle concepts. Without a user-stated need, such as replacement of aging F-16s with Joint Strike Fighters, technologists are forming their own ideas of what the UCAV should be able to do. Many of these people have been in the business of developing piloted aircraft, so their starting point for formulating a UCAV concept seems to be based on the idea of removing the pilot from a fighter aircraft. This approach is not necessarily wrong but could be constraining because of presumptions that UCAVs will operate like piloted aircraft.

Because of these assumptions, technologists are now preparing to spend research and development (R&D) resources to figure out how to do combat flight operations without a pilot on board. However, before R&D resources are spent, we should make sure we are solving problems that need to be solved. We need to ask some basic questions that could affect the ultimate cost and complexity of the system. For example, do we need to operate from a runway? Must the UCAV fly over and among civilians? Does it need to fly in formation? Is air refueling necessary? Must it drop expensive smart munitions?

Before proceeding to design a fighter without a cockpit, developers should step back and look at the attributes a weapon system should have. My premise is that if the above questions are asked, the answers will come back negative. A resulting system will more closely resemble a cruise missile rather than a piloted aircraft in terms of size, cost, and method of launch, except that it will drop its warhead and come back for a quick turnaround for another mission.

Desirable UCAV Attributes

Characteristics that one would wish to see in a UCAV include affordability, lethality, survivability, supportability, deployability, flexibility, and responsiveness.

Affordability

Since aircraft cost is roughly proportional to size, the vehicle should be as small as possible. And since range and payload determine size, vehicle and operational concepts that minimize required range and payload weight would have an advantage in unit production cost.

To minimize range requirements, one should free the UCAV from runways and airfields to allow forward basing. It could rocket-launch from a truck, like the old ground launched cruise missile. But how could one recover it in the field? Perhaps it could land in any open field on air bags, rather than wheels, that would inflate immediately prior to touchdown. A slow final approach similar to that used in short takeoff and landing (STOL) operations would minimize bounce and roll.

To minimize payload weight requirements, one should use small bombs in UCAVs and minimize the onboard sensor suite. A cheap UCAV that drops an expensive smart bomb wouldn’t help overall affordability, so the system should be able to precisely deliver cheap, unguided munitions.

To minimize the number of personnel required to operate UCAVs, one should make each vehicle as autonomous as possible, while maintaining the flexibility to react to the fluid mission environment. Remote teleoperation would be impractical and costly. A controller/operator should be able to give orders to multiple UCAVs, with each UCAV having the onboard smarts to generate and fly an appropriate trajectory, given the mission’s constraints and the current situation.

Lethality

Piloted aircraft must stand off for survivability, making guided munitions necessary. A small UCAV could take advantage of low signature and high maneuverability to safely release cheap, unguided ordnance very close to the target. With no humans aboard to black out, G-force levels could be increased. If a “smart” bomb’s terminal guidance package were on the UCAV, the vehicle could be used to provide smart guidance for a “dumb” bomb until reaching very close range, at which point the UCAV would release the unguided ordnance and snap into a high-G escape maneuver. The short range at release would ensure accuracy.

Survivability

One should expand survivability to include the time between flights, since forces should not be vulnerable to attack while on the ground. Given the threat posed by enemy cruise missiles, runway-based strike assets will be vulnerable to cruise missile attack.2 Dispersed basing schemes would make UCAVs harder to locate and attack.

One should also note the difficulty in shooting down a cruise missile flying at very low altitude.3 The same problem would apply to the enemy in attempting to shoot down our UCAVs. For that reason, UCAVs should have the capability to navigate and attack from very low altitude, if necessary for survivability.

Supportability

UCAVs should be easy to maintain in the field. They should be modular and reliable so that when parts do break, one can simply throw the modules away. Remaining serviceable modules could be matched to make a functional UCAV.

Deployability

When the air expeditionary force arrives, the reception may not be friendly. For that reason, UCAVs should be able to arrive by air and launch a strike prior to landing. This means launching from the wing of a B-52 or from the back of a C-17. Further, one should provide only a minimum of support gear and personnel. The number of UCAV controllers and control stations per UCAV should be kept small.

Flexibility

Single-purpose systems should be avoided. Commanders in chief would like their in-theater systems to be able to respond to any need. (Note the pictures of F-15E Strike Eagles loaded wall to wall with fuel tanks and air-to-air missiles in Operations Desert Shield/Storm.) UCAVs shouldn’t be designed with only one mission in mind.

Responsiveness

A UCAV would take full advantage of the “system of systems” and “information dominance.” Reliance on off-board sensors would minimize the onboard sensor suite requirements as well as provide greater situation awareness and flexibility. A UCAV and its operator would be aware of the updated battle situation and be able to adjust to changes in threats or weather. The target might be changed at the last moment by command and control.

A UCAV battle manager or controller wouldn’t be capable of replanning the details of each UCAV mission for each threat update off the network broadcast. Consequently, the UCAV must have significant autonomous capability to respond to threat updates and replan its mission in flight within the constraints of its fragment of the air tasking order and fuel availability. A robust onboard flight-management capability would help to minimize the data-link bandwidth required. The operator would also need to have the ability to immediately assume direct manual control over the UCAV’s flight path to respond to real-time maneuvering requirements.

Affordable UCAV Concept

Considering these desirable attributes, an affordable UCAV would be capable of dispersed forward basing, as well as air and sea launch. An operator controlling multiple UCAVs would direct them to targets. Reconnaissance assets would provide the operator with target imagery and coordinates. The UCAV would precisely drop small, cheap bombs from low altitude using onboard terminal guidance seekers.

With this concept, one does not need to develop technology to permit many of the flying operations performed by pilots. That is, UCAVs don’t need to do the following:

Operate from Airfields

Such a requirement would introduce questions of how to safely move them around an airfield in large numbers, before and after flight, among piloted aircraft.

Fly among Civilians

There are concerns about how a UCAV would “see and avoid” other air traffic, a requirement for all piloted aircraft in controlled airspace in visual conditions. A small UCAV designed for deployment by means other than its own power would have no need to fly over and among civilians.

Fly in Formation

Pilots fly in formation to reduce the air-traffic-control burden, for mutual support in visual and sensor search, and for offensive coordination. These requirements do not apply to UCAVs. They wouldn’t fly through busy airspace or have to land on a busy runway when operating from remote forward sites. Off-board assets that make up the system of systems would supply mutual support in sensor coverage. And the remote human UCAV controller would handle strike coordination.

Air Refuel

For deployment, UCAVs could be carried under the wing of a B-52, in a C-17, or on a boat—or they could be prepositioned. Forward basing (land or sea) or air launch would extend the combat range. The use of small bombs and limited sensors would reduce payload weight and extend range.

Drop Smart Munitions

Survivability and lethality would be achieved through small size, low altitude, and maneuverability, rather than by standoff weapon delivery. Close-in weapon release would assure the accuracy of unguided ordnance.

Conclusion

An affordable UCAV won’t be an aircraft without a pilot. It will be more like a returnable, controllable, responsive cruise missile.

Wright-Patterson AFB, Ohio

Notes

1. New World Vistas: Air and Space Power for the 21st Century: Aircraft & Propulsion Volume (Washington, D.C.: USAF Scientific Advisory Board, 1995), 12.

2. See “Cruise Missile Threat Spurs Pentagon Research,” Aviation Week Space & Technology, 14 July 1997, 44–57.

3. Ibid.

The value of history in the art of war is not only to elucidate the resemblance of past and present, but also their essential differences.

—Sir Julian Corbett


Disclaimer

The conclusions and opinions expressed in this document are those of the author cultivated in the freedom of expression, academic environment of Air University. They do not reflect the official position of the U.S. Government, Department of Defense, the United States Air Force or the Air University.


[ Back Issues | Home Page | Feedback? Email the Editor ]