Operation Iraqi Freedom (OIF) highlighted, timely air mobility and sustainment of US
military forces continue to require attention. An article in Air Force Magazine
addressing early mobility lessons-learned from OIF noted that "demand for airlift far
exceeds supply, and senior USAF officers say it is time to expand the fleet. . . . Airlift
forces were pressed to their limits. . . . Gen. Tommy R. Franks, commander of US Central
Command, was forced to modify his original war plan to live within USAF's 'constrained'
airlift fleet. . . . [According to Gen John W. Handy, commander of the joint-service US
Transportation Command and the Air Force's Air Mobility Command,] 'I firmly believe we
need another Mobility Requirements Study.' "1
May 2004, the Department of Defense initiated a mobility capability study-called for in
the strategic planning guidance of 2004. According to Joint Staff briefing charts, the
study will "identify and quantify mobility capabilities required to meet the
end-to-end, full-spectrum mobility needs for all aspects of the national military
strategy.2 Also of interest, the secretary of defense's goal of being able to
"deploy to a distant theater in 10 days, defeat an enemy within 30 days, and be ready
for a new fight within another 30 days . . . will be used as a benchmark in the new
article proposes an approach for leveraging technological and operational innovation in
global air mobility that can provide a highly flexible, time-responsive means of globally
positioning and sustaining US military forces-not only on the land but also persistently
in the air. This approach, embodied in the technological and operational features of an
air-mobility concept known as the configu-rable air transport (CAT), offers a new
alternative to the force commander for addressing the mobility, sustainment, and
airpower-projection needs of twenty-first-century warfare.
CAT is envisioned as a C-5-sized aircraft that has more than twice the unrefueled range of
the C-5 and that carries an interchangeable module in lieu of the traditional fuselage.
Thus-like a fighter or bomber-this aircraft can be configured for a particular mission by
loading the appropriate airlift or airpower module. Depending upon the mission, the
flexible CAT could carry modules for Airborne Warning and Control System (AWACS),
missileer, traditional cargo, tanker, Army or Marine fire support (gunship), Navy sea
patrol, emergency communications for the Department of Homeland Security, fighting forest
fires, or international humanitarian relief, among others. Mission by mission, if
warranted, individual aircraft in the CAT fleet could be reconfigured to respond
rapidly to changing air--mobility, sustainment, and airpower-projection needs worldwide.
mobility-system concept should prove attractive for modernizing the aging elements of the
current air-transport fleet for two reasons. First, the CAT would provide a modern,
global-range aircraft with standardized performance, basing, support, crew, and training
that could offer, through the use of missionized modules, a modernization path for many of
today's transport aircraft such as the C-5 airlifter, as well as the E-3 AWACS, KC-135
tanker, E-8C Joint Surveillance Target Attack Radar System (JSTARS), C-9
aeromedical-evacuation aircraft, and the B-52 bomber. Second, the use of missionized
modules enables the introduction of new mission capabilities without reducing current ones
or requiring costly and time-consuming modification of the CAT aircraft. Together, these
features provide an attractive acquisition option for developing a new mobility system
that would not only replace a broad range of aging aircraft as they reach the end of their
economic lives, but would also continue to provide state-of-the-art warfare capabilities
through the development and introduction of new or upgraded mission modules.
article begins by examining an earlier modular aircraft-the Fairchild XC-120. Following a
technical description of the CAT and its mission modules, the advantages of using these
modules for transporting war materiel are addressed, with particular attention to
establishing high-throughput global air bridges, prepositioning forces at regional bases,
and rapidly moving air and land forces forward into bare bases. The article concludes with
a description of how the multiday endurance capability inherent in such a new global-range
transport, when equipped with airpower mission modules, would enable persistent airpower
operations to be employed. This would provide new options for flexible and highly
responsive global airpower projection similar to that proposed by the Navy in its
"sea strike" and "sea basing" concepts. It would also provide new
options for homeland security.
XC-120 "Pack Plane"
1949, shortly after the initiation of production of the C-119 "Flying Boxcar"
transport for the Air Force, that aircraft's manufacturer, Fairchild, experimented with a
design variation that incorporated a detachable fuselage module (fig. 1). Called the
XC-120 "pack plane," the transport aircraft lent itself to rapid reconfiguration
in support of a variety of missions. One description of the XC-120 mentions that modules
could deliver cargo as well as serve as shops, weather stations, emergency hospitals, and
1. Fairchild XC-120 pack plane with detachable module. Courtesy
of History Office, Air Force Aeronautical Systems Center.
Air Force ordered production of over 1,100 C-119 aircraft but did not pursue the XC-120.
Since then, other approaches for designing a modular air transport have undergone
conceptual definition in the United States and overseas. Like the XC-120, these did not
attract serious interest by potential government or industry customers. Instead, industry
stayed with the traditional tubular fuselage and wing-tail transport design that yielded
aircraft optimized for and generally dedicated to a single mission, such as passenger
carriage, large-cargo transport, and so forth. Today, as the Air Force assesses future
air-mobility and airpower needs and solutions, the idea of a modular transport aircraft
deserves renewed investigation.
CAT is a C-5-/747-class aircraft that uses a blended-wing-body (BWB) design capable of
carrying one interchangeable, missionized module (fig. 2).4 The BWB concept is
a modern version of the Burnelli lifting fuselage and Northrop flying-wing concepts of the
1920s, 1930s, and 1940s.5 Since the mid-1990s, the National Aeronautics and
Space Administration and the commercial aircraft industry have conducted technical
evaluations of BWB designs and identified their potential for signifi-cant improvements in
aircraft performance and reduced empty weight.6
2. Configurable air transport and detachable module. (Prepared
by Dennis Stewart and Isiah Davenport, General Dynamics, Advanced Information Systems.)
a modified BWB for the CAT offers several advantages over traditional wing-tubular
fuselage designs. In addition to having ample volume to carry the quantity of fuel needed
for global range-usually 7,000 nautical miles (nm) or more-it also has sufficient volume
for stowing the long landing gear required for the modular concept and for installing
active self-defense systems, such as air-to-air missiles and directed-energy weapons.7
The central area of the BWB, located behind the cockpit and over the module, can
accommodate approximately 100 passengers in a manner similar to the C-5 Galaxy's upper
deck. Alternately, one could configure the CAT's upper deck to provide crew-rest
facilities for global-range cargo-delivery missions and for the new operational concept of
persistent airpower operations, discussed later. Another design advantage is that the flat
lower surface of the BWB design facilitates the mating of the large mission modules.
Finally, the BWB's top-mounted engines should enhance survivability, reduce noise during
takeoff and landing, and enhance multimission flexibility. For instance, this engine
location opens up clear lines of sight for sensors and weapons mounted on the module,
providing improved flexibility to configure modules to support a broad range of electronic
and force-application missions. It also may enable the CAT to conduct amphibious
operations, such as combat search and rescue or at-sea replenishment, with an appropriate
amphibious landing module.
conceptual CAT configurations in this article's illustrations reflect sizing to provide
the same cargo volume as the C-5 but with approximately twice the unrefueled range. As a
baseline for comparison, the C-5 is capable of carrying a maximum aircraft cargo load
(ACL) of 178,000 pounds (89 tons) to an unrefueled range of approximately 3,200 nm. It has
a maximum peacetime takeoff weight of 769,000 pounds, a wingspan of 223 feet, and a
maximum fuel capacity of 51,150 gallons (322,500 pounds).8
upon a conceptual BWB aircraft design assessed by Boeing for an 800-passenger transport,
the CAT concept carries a C-5-equivalent maximum planned ACL of 178,000 pounds (89 tons)
to an unrefueled range of approximately 7,000 nm. This payload would correspond to 27 463L
pallets, each with an average load of approximately 6,600 pounds. These figures yield an
aircraft with a maximum takeoff gross weight of about 820,000 pounds, a wingspan of 280
feet, and a maximum fuel load of about 40,000 gallons (270,000 pounds).9
BWB-based improvement in unrefueled global range of the CAT, when carrying the same
payload weight as the C-5, has significant economic and operational advantages because of
the reduced need for air refuelings and en route bases. This, in turn, leads to a
reduction in both mission costs and total mission assets required. For example, aerial
refueling costs approximately $175,000 for every 10,000 gallons.10 For a
global-deployment mission of 6,000 nm, the C-5 requires two KC-135 tankers transferring a
total of 28,600 gallons.11 Using the global range of the CAT to replace just
one such C-5 air-refueled mission each month yields a mission cost reduction of
approximately $6 million per CAT per year-or approximately $300 million for each CAT over
its expected 50-year lifetime.
typical CAT module would measure about 150 feet in length, 30 feet in width, and 17 feet
in height. Internally, the module would have a 67-feet-by-27-feet flat floor (1,809 square
feet) with a clear ceiling height of approximately 12 feet. The flat floor could
accommodate 27 463L cargo pallets or rolling stock, with additional cargo stowage in the
nose and tail cones. An unfurnished module would have an empty weight of about 75,000
pounds. Its upper surface would mate to the lower surface of the BWB by means of an
electrically powered clamping system. The module's power system, on the order of 2,500
horsepower, would power an air-cushion system providing module -mobility on the ramp and
enabling the module to be positioned for mating to the CAT.12 The
self-contained power system would also provide auxiliary electrical power and
environmental control for the module in flight and primary power when on the ground.
modules would come in several basic configurations. One intended for frequent use (e.g.,
day-to-day cargo movement; AWACS; missileer; tanker; passenger transport; and aeromedical
evacuation) could be fabricated using conventional methodology for aircraft design and
assembly. Such a module would likely have a useful life of 25 years or more. Those
intended for the surge transport of war materiel, including modules configured to support
bare-base operations, could be built using alternative manufacturing methods and materials
when lower production costs and increased production rates are emphasized. The goal would
be an "expendable" module design enabling the economical production of hundreds
of "war-ready" modules for placement in ready storage during times of peace,
while also enabling the rapid and affordable replenishment of modules expended during
Handling and Transport
handling and transport involve the basic operations of receiving, organizing, loading,
transporting, unloading, warehousing, and distributing cargo from the point of origination
to the end user. Several approaches have sought to improve the throughput efficiency of
this process, starting with the most obvious of increasing the speed of the transportation
system. After attainment of the maximum economic cruise speeds, further improvement
requires a more fundamental change in the cargo-handling process.
Cargo Transportation Using Standardized
land-sea cargo transportation, a revolutionary improvement in throughput occurred in the
mid-1950s by applying an idea that originated in the late 1930s-using standardized,
intermodal cargo containers for both land and sea transportation.13 This
approach resulted from recognizing that loading cargo containers from trucks to ships and
back to trucks was far more time efficient than the millennia-old manual handling of
individual pallets, boxes, bags, vehicles, and so forth. The new containerized approach
reduced the nonrevenue-generating time of both ships and trucks by lessening the time
spent waiting and finally loading and unloading. Consequently, one needed fewer ships,
trucks, and dockside workers for a given throughput and revenue-generating capacity.
Because of today's improved material-handling automation, computerized tracking of cargo
containers, permanent dockside material-handling equipment, and well-trained personnel,
workers need fewer than 50 hours dockside to unload and load a 3,000-container
"lift-on/lift-off" cargo vessel. Ship-utilization efficiency-the time actually
spent transporting cargo and generating revenue-comes to approximately 85 percent for
Loading and Unloading from the CAT
the CAT modular concept speeds the loading and unloading of the cargo, thus improving the
overall transportation-utilization efficiency of the aircraft and minimizing the required
ramp space. Examination of movies of the XC-120 module's unloading operations and a
simplified visualization of detaching a module from the CAT suggest that it may be
possible to drop a module in as little as 10 minutes following arrival at the designated
module-release spot on the ramp. For the one-way transfer of cargo into an air base, the
CAT would land, taxi, drop the module, taxi, and then take off without stopping the
engines. The total time spent on the ground might amount to only 20 minutes. By way of
comparison, the C-5's ground time for unloading cargo without refueling or reconfiguration
is 120 minutes.14
a module to a CAT, however, will be more complex. We could use an automatic mating system
on the CAT that precisely locates the module and provides guidance cues so that the pilot
can accurately taxi the aircraft into position above the module. After final alignment of
the module using the air-cushion system, the actual mating would take about 10 minutes
since it would involve the same basic aircraft and module operations used to drop a
module-only conducted in reverse.
preliminary time allocation, consistent with the assumptions above, indicates a total CAT
time on the ground of approximately 140 minutes: 10 minutes for taxiing following landing,
10 minutes to drop the module, 60 minutes to taxi and refuel the aircraft, 20 minutes to
taxi and position the CAT to pick up the next module, 10 minutes to pick up a module, 20
minutes for anomaly resolution and final checks, and 10 minutes to taxi to the runway for
takeoff.15 Without refueling, the total time would approach 80 minutes. If
crews could refuel the aircraft and load/unload the module simultaneously by using the
mobility of the modules to move them to and from the CAT during refueling, then the total
ground time would also come to about 80 minutes. The C-5, for comparison, requires 500
minutes of planning ground time for unloading cargo, refueling, reconfiguring the cargo
compartment, and loading cargo.16
Model of a CAT Air Bridge
first-order system-dynamics simulation of a CAT air bridge identified the number of
aircraft needed, based on assumptions for flight frequency and ramp-space requirements at
the aerial port of debarkation (APOD). This model simulated a global-delivery mission to a
distance of 6,500 nm without air refueling or en route base stops-for example, one
way from McGuire AFB, New Jersey, to Qatar in the Persian Gulf. At an assumed departure
rate of three CATs per hour, 84 aircraft would establish a constant-throughput air bridge,
delivering 72 modules carrying an average of 4,400 tons per day (using a planning cargo
load of 61.3 tons) for an airlift capacity of 28.6 million ton-miles per day.17
Using the assumptions stated above for ground operations for nonsimultaneous
unloading/loading of modules and fueling activities, one would need seven ramp parking
places at the APOD to swap modules, refuel the CATs, and prepare for the return flight.
The total round-trip time from departing the aerial port of embarkation (APOE) to
departing for the next trip is approximately 31.5 hours. One would also need a minimum of
seven ramp parking spaces at the APOE. Turning to the C-5 once again, one sees that the ideal
maximum daily cargo throughput for 52 arrivals per day, assuming seven ramp parking
places, carriage of the maximum ACL, no reduction for ramp-queuing inefficiencies, no
loading constraints, and no en route air refueling or basing constraints, would
amount to 3,200 tons.
simple air-bridge model was applied to the movement of a 5,000-person Army brigade with
12,000 tons of materiel to a distance of 6,500 nm. A planning cargo load of 61.3 tons was
assumed, as was the fact that each CAT could also carry up to 100 soldiers in the upper
deck. With a 20-minute departure spacing, the 84 CATs completed the movement of personnel
and cargo in approximately 95 hours from the time the first aircraft departed the
continental United States (CONUS) until the last one returned and had been unloaded and
refueled. With a 30-minute departure spacing, 56 CATs completed the needed 196 missions in
approximately 127 hours. Focusing on the 10-day deployment goal of the aforementioned
mobility-capability study, one sees that each 84-CAT air bridge would be capable of
delivering 41,000 tons of war materiel or about three Army brigades.
criticism of the comparison of air-bridge models of the CAT and C-5 points out that the
cargo in the module unloaded from the CAT is not necessarily unloaded, whereas the ideal
throughput for the C-5 includes unloading the cargo. This is not actually the disadvantage
it appears to be. The primary objective of using modules for moving cargo is to improve
utilization efficiency of the transport aircraft. Detaching the module, moving it away
from the aircraft parking spaces, and then unloading it all help to ensure a high
CAT-utilization efficiency by preventing difficulties in unloading cargo-engines on
rolling stock that will not start, jammed cargo restraints, lack of sufficient unloading
crews or equipment, and so forth-from interfering with the processing and departure of the
CATs. Further, depending on available ramp space, it is not necessary to unload the
modules immediately since they provide environmentally protected and controlled storage of
the cargo. A ramp area of 2,500 feet by 600 feet at the APOD could store approximately 100
modules containing 6,100 tons of war materiel. Also, with appropriate training, the
arriving troops (as in the above example of the Army brigade) could unload their own
equipment without the need for large numbers of Air Force personnel. Additionally, the
emptied modules could serve as temporary shelter until their return.
Limitations on Fuel Availability
other large air transports, the CAT requires a secure and plentiful supply of fuel. In the
air-bridge example cited above, if the CATs required refueling at the APOD, the daily
pumping requirement would reach approximately three million gallons. To meet these needs,
the base would require a substantial hydrant-fueling network and fuel-storage capacity.
Since forward locations will probably not include such facilities, one approach for
establishing high-throughput transport of modules into an area like this would involve
flowing the CATs through a network of regional bases (described in the following section)
to the APOD. (Andersen AFB, Guam-a potential regional base in a global CAT distribution
network-has a fuel-storage capacity of approximately 66 million gallons.)18 The
global-range capability of the CATs permits them, unlike the C-5s, to fly 3,000 nm from
the regional base into the APOD and return the same distance to the base without either
refueling at the APOD or air refueling en route. One could establish APODs to handle a
throughput of up to 2,900 tons per day, with a planning cargo load of 61.3 tons, at
forward locations that would otherwise not be available due to a lack of aircraft-fueling
capacity. A continuous 3,000 nm air bridge from the regional base to and from the APOD,
with 30-minute spacing, would require 28 CATs. Moving the Army brigade, for example, would
require about five days to complete. Because the aircraft would not have to refuel at the
APOD, they would need only three ramp parking spots to sustain this throughput.
could establish a network of CONUS and overseas regional bases-for example, eastern and
western CONUS, Hawaii, Guam, Alaska, Diego Garcia, and western Europe-to support the rapid
global delivery of CAT modules to APODs located in most locations of interest (fig. 3).
The longest route length, using a great circle, comes to 5,200 nm. The unrefueled global
range of the CATs would allow them to move between these bases without en route air
refueling. With this operational model, including an overlay of 3,000 nm operating radii
from each of the bases, CATs transporting modules would then fly from the CONUS APOE to
pick up the loaded module and then to the APOD, using regional bases for fueling and crew
rotation. Returning CATs would pick up empty and unneeded modules and bring them back
through regional bases to CONUS terminals for reuse.
Prepositioning and Rapid Delivery
of materiel to support the rapid deployment of military forces has become increasingly
important. The CAT modules provide a means to environmentally protect, preload, and
securely store the first-entry combat forces' air-transported equipment, supplies, and
forward-base facilities in the CONUS and at regional bases without using permanent
ware-houses. After activation of such forces, crews could "float" the modules
containing stored equipment on the modules' air cushions to the designated module-loading
location on the ramp to await arrival of the CATs and initia-tion of the air bridge to the
of preloaded modules integrates well with the global unrefueled range of the CAT. The
CATs' ability to fly to an unrefueled range in excess of 10,000 nm (without modules)
allows the rapid repositioning of these aircraft with minimal or no demand for en route
basing or air refueling. In case of an emergency, designated CATs conducting normal
air-mobility missions worldwide would land at a US or allied air base, drop their modules,
and refuel. Less than 90 minutes after landing, the CATs would be en route to the
designated regional base, where they would pick up prepositioned modules and carry them
forward to an APOD or, as discussed later, under-take airpower-projection missions.
tanker module will allow CATs to function as strategic tankers. For mission-assuredness
purposes, such a module would have twin, high-capacity refueling booms to support the
refueling of large aircraft such as the B-1, B-2, C-17, and C-5, as well as other CATs.
The tanker module would have an off-load capacity of approximately 200,000 pounds at an
operating radius of 3,000 nm from the CONUS and regional bases (fig. 3). On a
shorter-duration mission-radius of about 500 nm-additional fuel from the CAT's wing tanks
could increase the off-load capacity up to approximately 350,000 pounds. The KC-135E, in
comparison, has an off-load capacity of 101,200 pounds and 10,500 pounds at mission radii
of 500 nm and 2,500 nm, respectively.19
3. CAT module and tanker coverage from the CONUS and regional bases
providing tanker capability can be equipped to dispense fuel while parked on the ground.
With a storage capacity of approximately 35,000 gallons and a self-powered fuel-pumping
system, these modules could store and dispense fuel at forward bases-an important feature
since ever-more US aircraft and ground equipment use the same JP-8 fuel. Hence, CAT
tankers could use the module to escort tactical aircraft to an in-theater air base and
then leave the module to support local air and ground operations.
addition to the use of tanker modules for dedicated air-refueling missions, all CATs will
probably feature permanent, wing-mounted refueling systems to air-refuel fighters and
unmanned aerial vehicles (UAV). Installing a lower-capacity boom on one wing and a
probe-and-drogue system on the other would permit all CATs, regardless of the transport or
airpower-projection mission performed, to serve as emergency en route tankers and permit
airpower-projection CATs to "top off" fighter escorts.
forward deployment of military forces often requires the establishment of operations at
bare bases-that is, air bases or commercial airports where the runways, taxiways, and
ramps are usable or rapidly repairable but where the supporting capabilities, such as fuel
storage and power generation, are either not available or not readily repairable. To
support the deployment of military forces into these bases, the Air Force uses
prepackaged, transportable bare-base kits called Basic Expeditionary Airfield Resources,
assembled at the bare base by Air Force civil-engineering teams.
modules provide a new approach for these kits. Instead of using tents and erectable
buildings, base personnel could utilize special versions of the CAT war-ready module for
shelter. We can easily visualize the establishment of initial tactical air operations at a
bare base using missionized CAT modules (fig. 4). In this example, a delivery rate of up
to four modules per hour reflects the circumstance that CATs would not pick up modules for
the return flight and that these aircraft do not need refueling. This delivery rate yields
a total timeline of approximately seven hours:
4. Bare-base buildup. (Prepared by Dennis Stewart and Isiah Davenport, General
Dynamics, Advanced Information Systems.)
= 0 hour. Initial security forces and base-opening civil engineers arrive via C-130s.
Planned module locations have been preestablished, based upon satellite and UAV
Time = +2 hours. CATs deliver three modules for air base defense, and crews move them on
the modules' air cushions to defensive locations away from the ramp. Two modules contain
surface-to-air missiles and Phalanx-type air defense guns, while a third contains an
antimissile/aircraft laser and target-acquisition radar. Laser defenses would also protect
against artillery, mortar, rocket, and similar munitions. Operating crews for these
defensive systems, as well as additional Air Force civil engineering teams, fly to the
bare base in the upper deck of the CATs that deliver these modules. A fourth CAT, on the
ramp (fig. 4, upper right), delivers the first Army module containing more ground-defense
Time = +3 hours. Four Army modules (fig. 4, lower left) containing up to 245 tons of
equipment and 400 soldiers arrive. After they empty the modules, personnel use them for
temporary quarters and protection against chemical, biologi-cal, and small-arms attack.
Time = +5 hours. Six modules designed to support tactical air operations arrive and are
placed at the far end of the ramp. Personnel erect air-supported canopies between the
modules to provide shelter for conducting maintenance and weapon loading on the tactical
aircraft (fig. 4, lower right). Air Force civil engineers as well as operational-support
personnel arrive in the CATs that transport these modules.
Time = +7 hours. The final four modules containing fuel, water, and munitions arrive, as
do the tactical aircraft in preparation for initiating local air operations. Subsequent
deliveries replenish these modules and return the empty ones for restocking.
bare-base CAT modules would be specially designed for this application, providing nuclear,
chemical, biological, environmental, acoustic, and ballistic protection for
forward-deployed forces. They might also contain active self-defense capabilities,
including tactical lasers. The auxiliary power system used to run the air cushion would
also provide electrical power and environmental control. The configu-ration of the
interior of the modules would incorporate many specialized logistical-support functions
that would normally require the erection or assembly of separate facilities-air and space
operations centers, secure communication facilities, crew quarters, hospitals, mess
facilities, maintenance shops, small-arms arsenals, fuel-storage areas, munitions
shelters, recreation facilities, and so forth. Upon completion of the mission, crews would
reload the modules on the CATs for return to the CONUS for cleaning, repair, and
replenishment. Many of these modules would also prove useful in -humanitarian-relief
operations. A key feature of this use of CAT modules is the ability to repack and relocate
them quickly. In the example above, four CATs with tanker support could relocate these
modules to another base 1,000 nm distant in about 20 hours, thus providing substantial
flexibility for repositioning theater air forces as the operational campaign unfolds.
early 1929, shortly after Charles Lindbergh's famous 34-hour flight in 1927, Maj Carl
Spaatz and Capt Ira Eaker of the US Army Air Corps initiated an effort to investigate
long-endurance flight.20 In the Air Corps's three-engine Fokker C-2A Question
Mark, they, along with Lt H. A. Halverson, Lt E. R. Quesada, and Sgt R. W. Hooe,
established an initial endurance record of just over 150 hours, involving 42 air-refueling
and resupply hookups. In one of many endurance efforts undertaken later that year, Dale
Jackson and Forest O'Brine established a new record of 420 hours in a single-engine
Curtiss Robin, increasing the record in 1930 to 647 hours in the same plane.21
Five years later, brothers Fred and Algene Key extended the record to 653 hours (27 days),
again in a single-engine Curtiss Robin.22 In this 1935 record flight, the Keys
completed 432 hookups to transfer fuel, oil, and supplies and flew a ground track of over
70 years later, one has trouble locating these endurance records in the history books.
Contemporary planners regard the 40-hour missions of B-2s as remarkable and assume they
are pushing the edge of the envelope of human and hardware endurance. Yet, clearly this is
not the case. In fact, this area of potential technology exploitation can lead to the
establishment of a new paradigm of persistent airpower operations in which we could fly
critical military capabilities into forward air bases. Such capabilities would provide
persistent deterrence or force application when land bases are unavailable/threatened or
when sea-based forces have not yet arrived. With suitable onboard areas for crew rest and
multiple flight crews, persistent airpower operations with CATs would begin to emulate
naval operations with a corresponding influence on the types of airpower capabilities
used, joint operations undertaken, and Air Force and joint doctrine executed.
December 2002, Vice Adm Cutler Dawson and Vice Adm John Nathman of the US Navy discussed
the advantages of the persistent forward projection of sea power:
Strike is a vision of what we will become as well as the focus of our capability today. It
is about far more than putting bombs on target, although the delivery of ordnance remains
a critical function. At its heart, Sea Strike is a broad concept for naval power
projection that leverages C5ISR (command, control, communications, computers, combat
systems, intelligence, surveillance, and reconnaissance), precision, stealth, information,
and joint strike together. It amplifies effects-based striking power through enhanced
operational tempo and distant reach. It takes U.S. power to the enemy 24 hours a day, 7
days a week, creating shock and awe both immediately and persistently. Sea Strike is what
it takes to win in the 21st century.23
in January 2003, Vice Adm Charles W. Moore Jr., US Navy, and Lt Gen Edward Hanlon Jr., US
Marine Corps, discussed the twenty-first-century advantages of sea basing:
Basing is the core of "Sea Power 21." It is about placing at sea-to a greater
extent than ever before-capabilities critical to joint and coalition operational success:
offensive and defensive firepower, maneuver forces, command and control, and logistics. By
doing so, it minimizes the need to build up forces and supplies ashore, reduces their
vulnerability, and enhances operational mobility. It leverages advanced sensor and
communications systems, precision ordnance, and weapons reach while prepositioning joint
capabilities where they are immediately employable and most decisive. It exploits the
operational shift in warfare from mass to precision and information, employing the 70% of
the earth's surface that is covered with water as a vast maneuver area in support of the
could realize many of the operational advantages inherent in "sea strike" and
"sea basing" through persistent airpower operations involving CATs. Operating
from the network of regional bases described earlier, groups of perhaps as many as eight
CATs with appropriate airpower modules could patrol designated areas within a 3,000 nm
radius of the regional or CONUS base for periods of several days (fig. 5). CAT tankers
operating from these same bases would air-refuel the patrolling CATs every 12 to 18 hours.
These "air battle groups" would provide the ability to rapidly establish air
superiority, demonstrate national resolve, support allies, and, if necessary, project
airpower without the need to first establish forward land-operating bases within the
theater of operations. These persistent airpower operations would emulate deep-ocean naval
operations but with the advantage that the entire surface of the planet would become
5. CAT AWACS, cargo, unmanned combat air vehicle (UCAV) flying tender, and
direct-fires-support module. (Prepared by Dennis Stewart and Isiah Davenport,
General Dynamics, Advanced Information Systems.)
an air battle group might consist of CATs carrying the following types of modules:
Integrated flight-operations center, AWACS, and JSTARS for battlespace situational
awareness and battle-group command and control (C2).
Airborne laser for missile defense and self-defense of air battle group.
Standoff-attack module carrying 50 2,000-pound missiles capable of Mach 7 speed and a
range of 1,000 nm for rapid, precision strike.
Ballistic-missile-defense module carrying 40 3,000-pound air-launched antiballistic
missiles for defense against theater ballistic missiles.
Direct-fires-support module carrying twin 155 mm cannons; multiple tactical lasers; and
medium-range, precision-attack munitions to provide sustained fires support for special
operations forces and to defend US and allied forces, including forward bases.
UCAV flying tender carrying two Mach 3.5 UCAVs and 400 precision-attack munitions to
conduct battlespace surveillance and attack.
CAT tankers for refueling fighter escorts.
as the US Navy puts its carrier battle groups to sea during times of increased threat as a
show of force and to increase forces deployed forward, the air battle group offers similar
possibilities for airpower. These unique CAT advantages-global unrefueled range, which
enables the quick repositioning of CATs; rapid mission reconfiguration using airpower
modules prepositioned at regional bases; and multiday endurance with refueling-allow the
Air Force to rapidly assemble, project, and sustain airpower virtually anywhere in the
world. Within 12 hours or less, if CAT air battle groups are already airborne, the Air
Force could provide a first and signifi-cant response to threatening forces or could
engage attacking forces with substantial, long-range, precision firepower. Within 24 to 36
hours, we could globally reposition, refit, and send forward 10s of additional CATs to
sustain the initial airpower operations and link up with other arriving joint forces. CATs
could become core elements of the military's "first-response" air and space
CAT concept would also support homeland defense. CATs flying multiday air-patrol missions
could undertake missions such as ISR, ballistic and cruise missile defense, counter
smuggling detection, negation of captured airliners or ships, C2, and airborne
communications. CAT modules similar to those used for forward bare-base support could be
used for post attack support in areas temporarily isolated from ground access and
communication. Finally, one could possibly adapt CAT tanker modules to support fighting
forest, pipeline, and urban fires resulting from terrorist attack or other causes.
CAT UCAV flying-tender module (figs. 5 and 6) highlights the flexibility in new
operational approaches enabled by the CAT and its modules. In this concept, a CAT serves
as the flying tender for two 15,000-pound UCAVs, rearmed and refueled by the tender
module. Preliminary estimates indicate that each UCAV could carry four 250-pound
precision-guided weapons to an operating radius of 750 nm at a cruise speed of Mach 3.5.
Assuming the CAT orbits 300 nm outside "Red's" border, the UCAVs could strike
targets and conduct surveillance up to 450 nm inside of Red. At this maximum combat
radius, the UCAV would have a mission cycle time of approximately one hour. Each CAT
tender and its twin UCAVs could attack eight targets each hour or approximately 200
targets per day. At closer distances, each tender's UCAVs could attack up to 24 targets
per hour. The CAT's UCAV tender module would carry approximately 400 250-pound
munitions-enough for 100 reloads of the UCAVs.
6. Left: a CAT's UCAV flying-tender module. Right: an in-flight UCAV
by Dennis Stewart and Isiah Davenport, General Dynamics, Advanced Information Systems.)
UCAVs on each tender could also conduct 50 or more ISR sweeps within the battlespace
during each 24 hours to augment other air and space capabilities. Advanced communication
systems, perhaps using direct-line-of-sight lasers, would link the UCAVs and the tender
aircraft to provide real-time C2 of the former throughout most of the mission. Further,
outbound UCAVs could relay ISR data identifying high-priority targets to the C2 CAT, which
could then relay updated target lists to inbound UCAVs, thereby providing a responsive
Air Force relies upon the CRAF to augment organic military-transport capabilities during
times of crisis. The versatility of the CAT offers a new approach to providing crisis
augmentation. A government-owned, contractor-operated fleet of CATs, notionally called
Eagle Air (fig. 7) and manned by Air Force Reserve and retired aircrews, could
perform the bulk of the day-to-day movement of CAT modules to support peacetime operations
of the US military and humanitarian and peacekeeping operations of the US government. For
one weekend a month and two weeks each year, the CATs and their Reserve crews would train
with the assigned active duty air-mobility units. In times of crisis, these Eagle Air CATs
could then quickly activate, integrate into their active duty units, and conduct virtually
all of the air-mobility and airpower-projection missions.
7. A CRAF Eagle Air CAT loading Army rapid-deployment modules. (Prepared
by Dennis Stewart and Isiah Davenport, General Dynamics, Advanced Information Systems.)
need] a future force that is defined less by size and more by mobility and swiftness, one
that is easier to deploy and sustain, one that relies more heavily on stealth, precision
weaponry and information technologies.
George W. Bush
the ability to move and sustain US military forces is, as President Bush stated, critical
to preparing US military forces for the future and providing the president with the
military capability needed to effectively protect and defend the United States and its
allies.25 This article has attempted to respond to this need by describing how
advanced aeronautical technologies, combined with an innovative modular system
architecture, offer the potential to significantly increase the air mobility and
sustainment of US military forces. In particular, the article has sought to show how the
air mobility aspects of the secretary of defense's goal of being able to "deploy to a
distant theater in 10 days, defeat an enemy within 30 days, and be ready for a new fight
within another 30 days" may be achievable. Further, the article has tried to
demonstrate that this modular-system architecture may provide a cost-effective means of
modernizing our aging air-transport fleet with an innovative aircraft system that provides
air mobility, sustainment, and airpower-projection capabilities that will significantly
enhance the responsiveness and agility of US military forces well into the future.
John A. Tirpak, "The Squeeze on Air Mobility," Air Force Magazine 86, no.
7 (July 2003): 23, 24, 25, http:// www.afa.org/magazine/July2003/0703mobility.asp.
Jason Sherman, "DoD Study May Pit C-17s, Fast Ships vs. Fighters," Defense
News, 21 June 2004, 1.
The CAT is one of 66 futures war-gaming concepts defined and assessed in the Air Force
Technology Seminar game conducted by the Air Force Research Laboratory in 2000-2001 in
partnership with the Air Force Directorate of Strategic Planning.
"Northrop's Flying Wing Airliner," in Glen Edwards and the Flying Wing: The
Diary of a Bomber Pilot, The Warbird's Forum, November 2003,
"The Blended Wing Body: A Revolutionary Concept in Aircraft Design," NASA
Facts Online, 24 April 2001, http://oea.larc.nasa.gov/PAIS/BWB.html.
The notional CAT design includes a landing-gear configuration derived from the design of
the B-58 bomber of the late 1950s. The B-58 had a high wing-about 7.5 feet-and carried a
large centerline fuel pod. Its landing-gear design used a simple structural configuration
and fold mechanism that yielded an extremely light landing-gear weight fraction, despite
its long length.
Air Force Pamphlet (AFPAM) 10-1403, Air Mobility Planning Factors, 18 December
2003, 12, table 3, http://
www.e-publishing.af.mil/pubfiles/af/10/afpam10-1403/afpam10-1403.pdf; C-5 Galaxy Fact
Sheet, http:// www.af.mil/factsheets/factsheet.asp?fsID=84; and C-5A/B Galaxy,
These estimates are based on aircraft size and performance for a large Boeing BWB
conceptual aircraft. See "Boeing Blended Wing Body Large Commercial
Transport," Jane's All the World's Aircraft, 14 July 2003, www.janes.com.
This assumes an average air-refueling cost of $17.50 per gallon of fuel, as reported in
"B-52 Re-engining, Financing Plan Endorsed," Air and Space Daily, 8 April
AFPAM 10-1403, Air Mobility Planning Factors, 18, table 11.
As an interesting point of comparison, General Motors recently showed a concept car that
included a 1,000-horsepower V-16 engine.
This idea, originated by Malcolm McLean in 1937, was not put into practice until 1956. His
Sea-Land Corporation initiated the concept of commercial, containerized cargo transport.
See http://americanhistory.si.edu/ onthemove/exhibition/exhibition_17_2.html. In 1950 the
United States Army developed a similar concept called "CONEX" that saw extensive
use in Vietnam; it has led to today's military use of intermodal containers.
AFPAM 10-1403, Air Mobility Planning Factors, 14, table 5.
This scenario assumes a hydrant system for refueling with two hookups to the aircraft,
each with an average flow rate of 450 gallons per minute. Onloading 30,000 gallons of fuel
would take approximately 45 minutes.
AFPAM 10-1403, Air Mobility Planning Factors, 14, table 5.
For C-5 planning cargo load, see ibid., 12, table 3.
A1C Claudia Garcia-Strang, "Andersen to Have Largest Fuel Storage Contractor to Turn
Over New Tanks Soon," PACAF News, 17 October 2002, http://www2.
AFPAM 10-1403, Air Mobility Planning Factors, 17, table 10.
"Flight of the Question Mark," USAF Museum History Gallery,
Capt Franklyn E. Dailey Jr., USN, retired, Socked In! Instrument Flying in Northern
Latitudes, 2002, appendix A, "Aviation Events, 1929-31,"
"Curtiss J-1 Robin: 'Ole Miss,' " Smithsonian National Air and Space Museum,
Vice Adm Cutler Dawson and Vice Adm John Nathman, USN, "Sea Strike: Projecting
Persistent, Responsive, and Precise Power," US Naval Institute Proceedings
128, no. 12 (December 2002), http://www.usni.org/ proceedings/Articles02/PROdawson12.htm.
Vice Adm Charles W. Moore Jr., USN, and Lt Gen Edward Hanlon Jr., USMC, "Sea Basing:
Operational Independence for a New Century," US Naval Institute Proceedings
129, no. 1 (January 2003), http://www.usni.org/ proceedings/Articles03/PROseabasing01.htm.
Department of Defense, Transformation Planning Guidance, April 2003, 3,
Michael Snead (BSAE,
University of Cincinnati; MSAE, Air Force Institute of Technology) is the lead for Agile
Combat Support in the Aeronautical Systems Sector, Plans and Programs Directorate, Air
Force Research Laboratory (AFRL), Wright-Patterson AFB, Ohio. He has also served as a
science and technology engineer at AFRL, focusing on futures war gaming and future
war-fighting concepts. Other positions at Wright-Patterson include lead structures
engineer, Aeronautical Systems Center; chief flight-systems engineer/ lead structures
engineer, National Air and Space Plane Joint Program Office; and project engineer,
Transatmospheric Vehicle Project Office. Currently Mr. Snead is chairman of the American
Institute of Aeronautics and Astronautics (AIAA) Space Logistics Technical Committee.
& Space Power Journal
Back to the publications list