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A SYSTEM DYNAMICS MODEL FOR MANAGING ATRCRAFT SURVIVABILITY
Donald R. Drew
Professor of Systems Engineering
Virginia Polytechnic Institute and State University
Blacksburg, VA 24061
ABSTRACT
The aircraft survivability model developed is comprised of five sub-
models: (1) Economy Submodel, (2) Budget Submodel, (3) Procurement Submodel,
(4) Attrition Submodel, and (5) Survivability Submodel.
The economy submodel generates the annual “Gross National Product" of the
United States and "Federal Government Budget".
The budget Submodel uses the output of the economy Submodel to determine
the "Department of Defense Military Budget". The DOD budget is broken down by
service and function (Procurement, Operations and Maintenance, and RDT&E).
In the Procurement Submodel, the "Procurement Budget for Combat Aircraft”
determined in the Budget Submodel is used to generate the parameters: "Acqui-
sition Budget for Combat Aircraft" and "Modification Budget for Combat Air
craft". The outputs of this submodel are the "Procurement Rate for Combat
Aircraft" and "Modification Rate for Combat Aircraft",
The Attrition Submodel acts on the inventory of "Combat Aircraft" in the
event of war. The number of combat aircraft increased by the outputs of the
Procurement Submodel over years of peacetime are reduced in wartime through
the "Attrition Rate for Combat Aircraft", which depends on the number of
“Combat Aircraft", the "Sortie Rate for Combat Aircraft", "Mission Surviv-
ability for Combat Aircraft", and the “Availability of Combat Aircraft.
The Survivability Submodel outputs are the "Mission Survivability for
Combat Aircraft" and the “Availability of Combat Aircraft". The former is
the product of the "Susceptibility of Combat Aircraft" and "Vulnerability
of Combat Aircraft", both of which depend on the magnitude of the "Aircraft
Survivability RDT&E Budget" outputed from the Budget Submodel. Reductions
in the "Susceptibility of Combat Aircraft" and "Vulnerability of Combat Air-
craft" affect the "Acquisition Cost of Combat Aircraft" and "Modification
Cost of Combat Aircraft" used in the Procurement Submodel.
Additional feedback loops between the submodels are generated by moni-
toring the "Relative Strengths of U.S.S.R./U.S. Airpower" and incorporating
the effects of this perception on the Economy Submodel, the Budget Submodel,
the Procurement Submodel, and the Survivability Submodel. Thus, the five
submodels interact to form a series of interacting positive and negative
feedback loops. - The positive loops reinforce themselves leading to increased
air power over time. The negative loops act through such constraints as
resource availability and spiraling procurement costs to suppress the growth
of air power.
INTRODUCTION
The U.S. lost 2561 fixed wing aircraft and 2587 helicopters in the
Viet Nam War [1]. As a result of the attrition rates in Southeast Asia,
the Joint Technical Coordinating Group on Aircraft Survivability (JTCG/AS)
was established in the 1970's. The JTCG is chartered to coordinate the
non-nuclear survivability research and development effort within the three
services (the Army, the Navy, and the Air Force) of the Department of
Defense.
This year the Virginia Polytechnic Institute and State University was
awarded a research grant to develop and implement a survivability management
model for use by advanced program planners. The model is to detail the
essential survivability management parameters and their causal relationships
throughout the life cycle of aircraft systems, and demonstrate the feas-
ibility of obtaining a desired level of functional capability through a
given approach and the connection between current needs and future returns.
Other aspects will include the forecasting of macro-behavior, predicting
consequences of proposed actions and failure to act, and the conducting of
sensitivity analyses to establish research and data. gathering priorities,
as well as providing aids to communication among those concerned with
survivability issues and in their understanding.
Aircraft combat survivability is defined by the United States Depart-
ment of Defense as "the capability of an aircraft to avoid or withstand
a man-made hostile environment without sustaining an impairment of its
ability to accomplish its designated mission" [2]. From this definition,
the broad scope of the concept of survivability is evident leading the JTC¢
to update its response to its charter requirements to include the promotion
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of survivability as 2 design discipline and the coordination of research and
development results among the military services and industry, as well as
within the services.
This research effort is organized into three phases of which this
Paper, the development of a pilot model, covers a significant portion of
the first phase. This phase is being accomplished using information avail-
able in unclassified material and through discussions with key personnel in
the survivability community. Emphasis during Phase 1 will be on the content
and structure of the model rather than on calibration. Phase 1, then, is
directed to demonstrating the usefulness of the approach,
Based on insights obtained during Phase 1, insights into the problem on
the part of the contractor and insights into the methodology on the part of
the sponsor, the detailed requirements of the final model will be determined
for completion during Phase 2. Phase 3 will address itself to implemen-
tation of the research by placing the package on a computer designated by
the JTCG and the scheduling of a series of workshops and short courses in
the use of the model for the benefit of personnel throughout the surviv—
ability community. By the end of Phase 3, the JTCG Survivability Design
Laboratory will be fully operational. It is estimated that the total
three phase research effort will require three years.
OVERVIEW OF THE MODEL
Fig. 1 is a conceptualization of the JICG Aircraft Survivability Model
that is being developed in this research. The JICG/AS Model is comprised
of five submodels: (1) Economy Submodel, (2) Budget Submodel, (3) Procure-
ment Submodel, (4) Attrition Submodel, and (5) Survivability Submodel.
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‘Throughout this report, visual representations or "causal diagrams" con-
sistent with the system dynamics methodology are used to communicate the
underlying structure of the survivability phenomenon, In Fig. 1 a few of
the key parameters are identified and the interactions between the para~
meters displayed using arrows (solid or dashed) and signs (plus or minus).
Since arrows denote the direction of causality, the two basic types of
parameters--constants and variables--are easily distinguished. A parameter
with only arrows emanating from it is a constant. Three types of variables
used in system dynamics are also apparent. Level or state variables appear
at the heads of solid arrows. Rate or change variables appear at the tails
of solid arrows. Other variables are auxiliary variables. The signs on
solid arrows tell whether the rate adds to or subtracts from the level
variable. Signs on the dashed lines tell whether the parameters at each
end of the arrow vary directly or inversely.
Starting in the upper left corner of Fig. 1, the Economy Submodel
generates the annual Gross National Product of the U.S, which, in turn,
determines the size of the Federal Government Budget. The two arrows
leading into "Federal Government Budget" from "Gross National Product"
and "Fraction of GNP to Government Budget" means that the Budget is a
function of the GNP and the fraction of the GNP that is taxed to generate
the budget. The plus signs on the arrows mean that the Federal Government
Budget increases (or decreases) as the GNP increases (or decreases), etc.
for "Fraction of GNP to Government Budget". Relationships between para~
meters depicted in the causal diagram greatly facilitate writing the
equations for the mathematical version of the computer model. Thus,
"Federal Government Budget" must either be the sum or product of "Gross
National Product" and "Fraction of GNP to Government Budget". Dimensional
analysis rules out the former.
The Budget Submodel uses the output of the Economy Submodel to deter-
mine the "Department of Defense Military Budget" each year. In this sub-
model, the DOD budget is broken down by service (Army, Navy, Marines, and
Air Force) and function (Procurement; Operations and Maintenance; and
Research, Development, Test and Evaluation).
In the Procurement Submodel, the "Procurement Budget for Combat Air—
craft" determined in the Budget Submodel is used to generate "Acquisition
Budget for Combat Aircraft" and "Modification Budget for Combat Aircraft”.
The outputs of this submodel are the "Procurement Rate for Combat Aircraft"
and "Modification Rate for Combat Aircraft".
The Attrition Submodel acts on the inventory of "Combat Aircraft"
in the event of war, The number of "Combat Aircraft" increased over the
peacetime years by the outputs of the procurement Submodel are reduced in
wartime through the"Attrition Rate for Combat Aircraft". The "Attrition
Rate" depends on the number of "Combat Aircraft", the "Sortic Rate for
Combat Aircraft", the "Mission Survivability for Combat Aircraft" and the
“availability of Combat Aircraft".
‘The key variable, "Mission Survivability for Combat Aircraft" depends
on the outputs of the Survivability Submodel. In turn, the "Availability
of Combat Aircraft" calculated in this submodel influences the “Attrition
Rate for Combat Aircraft" in the Attrition Submodel above. Focusing on
the Survivability Submodel in Fig. 1, survivability is a function of both
susceptibility and vulnerability. Susceptibility takes into account those
factors that determine whether the aircraft will be detected and hit by a
threat and vulnerability takes into account those factors that determine
whether the aircraft is killed by the threat mechanisms if it is hit. ‘The
magnitude of the "Aircraft Survivability RDT&E Budget" calculated in the
Budget Submodel determines “Actual Susceptibility of Combat Aircraft" and
“Actual Vulnerability of Combat Aircraft". The product of these gives
"Mission Survivability for Combat Aircraft" in the Attrition Submodel,
However, reduced susceptibility and reduced vulnerability increase acqui-
sition and modification costs which is accomplished in the model through
the "Survivability Enhancement Modification Cost Multiplier" and the
“Survivability Enhancement Acquisition Cost Multiplier".
The feedback between submodels is completed by monitoring the "Relative
Strengths of U.S.S.R./U.S. Airpower" (see Attrition Submodel). As U.S.S.R.
airpower increases with respect to U.S, airpower, an increasing "Function
of Government Budget to Defense" (see Budget Submodel) takes place, and
eventually, possibly, an increase in the "Fraction of GNP to Government
Budget" (see Economy Submodel).
The five submodels interact to form a series of interacting positive
and negative feedback loops. The positive feedback loops reinforce then
selves leading to increased air power. The negative feedback loops which
are coming more and more into play act through spiraling costs and have
already served to begin to reduce the increase in the conbat aircraft
inventory.
In the following sections the five submodels identified in Fig. 1 are
treated individually and in more detail.
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‘THE DEFENSE ECONOMY
National security depends upon many factors--military, human, techno-
logical and economic. In this submodel we try to interpret and define the
economic strength of the nation, as contrasted with its military forces.
As a beginning let us identify three levels of defense economics: (1) the
quantity of national resources available, now and in the future; (2) the
Proportion of these resources allocated the national security purposes; and
(3) the efficiency with which the resources so allocated are used, The
first, or highest level, is considered in this submodel.
For purposes of this model, GNP statistics are divided into mutually
exclusive, collectively exhaustive categories. The most commonly used
scheme for subdivision is that based on the International Standard Indus-
trial Classification (ISIC) [5]. The major ISIC categories, which are
Agriculture, Mining, Manufacturing, Utilities/Transportation, Construction,
Trade and Services, did not lend themselves well to the requirements of this
research and were therefore broken-down and reassembled to form four more
relevant categories": Aerospace Industry, Defense Industry (other than
aerospace), Air Transportation Industry, and Non-Defense Industry (other
than air transportation) [6] [7].
DEFENSE MANAGEMENT
In the previous section, organized around the Economy Submodel, we
considered the highest hierarchy of defense economics--the quantity of
national resources available, in this section, organized around the Budget
Submodel, the questions of the proportion of these resources allocated to
national security and the efficiency with which these resources are so
re addressed, Problems at
used--levels two and three in the hierarchy~
the second level are the special responsibility of the Bureau of the Budget
and the Appropriations Committees of Congress, although all executive
departments are deeply involved [17].
‘The remaining parameters in the Budget Submodel (some 116 of them
from DB-3 to DB-118) apply to the third or lowest level of the hierarchy.
Problems at this level--the efficient use of the resources allocated for
defense--are primarily internal problems of the defense departments and
agencies. The problems consist in choosing efficiently, or economically,
among the alternative methods of achieving military tasks, objectives, or
missions. These alternative methods may be different strategies, different
tactics, various forces, or different weapons.
NATURE OF DEFENSE PROCUREMENT
Military decisions may be classified by kind as well as’ by level.
It is useful to distinguish: operations decisions (strategy and tactics),
Procurement or force composition decisions, and research and development
decisions. The basic difference among these kinds of decisions, from the
point of view of analysis, is the time at which the decision affects the
capability of the military forces concerned. An operations decision can
affect capability almost immediately. A decision to procure something, on
the other hand, cannot affect capability until the thing procured has been
produced and fitted into operational forces. Finally, decisions to develop
something based on researching it tend to affect capabilities at an even
later date--after the system has been developed, procured and fitted into
operational forces. In this section we shall consider the procurement
function.
Basically the inventory of each of 23 combat aircraft is increased by
acquisition of new aircraft or modification of an older version of the same
type aircraft. Older version inventories are reduced by retirement and
modification to improved versions. Both the acquisition and modifications
rates depend directly on the acquisition and modification budgets and
inversely with acquisition and modification costs, The acquisition and
modification budgets are determined from the outputs of the Budget Submodel.
Having treated budgets for acquisition and modification of aircraft,
it remains to consider costs. The positive side of technological
substitution--lower casualty rates and a more efficient military--has
not come cheaply. U.S. tactical air power is perhaps the purest example
of this trade-off. The extent of the problem is easily illustrated.
During the peak procurement year of World War II (1943) the Army Air Corps
committed $2.5 billion to purchase tactical aircraft: fighters and light
and medium bombers of a dozen popular types. For fiscal year 1975 the Air
Force requested $1.1 billion to buy modern airplanes for the same tactical
purposes. The difference is that in 1943 the Air Corps got 25,000 planes
for its money; in 1975 the Air Force got 100. The average cost of a
tactical warplane procured increased from $100,000 in 1943 to $11,000,000
in 1975 [22]. Recent comparisons are no more heartening. Cost data on the
55 major weapons systems being produced by DOD in 1980 showed them to be 45%
higher than the original estimate. New tactical fighters for the air force
and navy will run from a low of about $11 million per plane for the F-16 to
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a high of about $24 million per unit for the F-14A. Even the navy's "low
cost" fighter, the A/F-18, will cost over $17 million a piece.
As to the future, procurement costs are projected to rise somewhat more
rapidly than the projected rate of inflation. The non-inflationary increase
is attributable to three factors: maximum technological substitution,
obsolescence, and procurement stretch-out [23].
Therefore, as we have stressed before, analysis focused on procurement
decisions, of necessity, will have to consider technological developments
and design alternatives on the one hand and operations--the strategy and
tactics with which each aircraft will be used when it is deployed--on the
other. In the modeling effort this is accomplished by tieing the Procure-
ment Submodel to the Attrition Submodels and the Survivability Submodel.
The Survivability Submodel establishes the magnitudes of the multipliers
affecting acquisition and modification costs in the Procurement Submodel.
As to the Procurement-Attrition interaction, referring to Fig. 1, we see
they are merely different aspects of the aircraft inventory adjustment
process, Attrition is considered in the next section.
TACTICAL AIR POWER
The Attrition Submodel is used to describe and to quantify the surviv-
ability of combat aircraft in encounters with hostile forces. Military
Standards and Military Handbooks identify numerous descriptors and summary
measures used to define the results of engagements between aircraft and
various threats [2][3]. In general, these measures address the probability
of survival per shot from a given weapon, probability of survival per
encounter with a given weapon, and probability of survival per sortie or
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mission during which an aircraft may have multiple engagements with the
various weapons of a zone defense. Aircraft probability of survival is a
summary measure that an aircraft will survive a defined level of damage or
Kill category--attrition, forced landing, mission abort, and mission avail-
able. In the model the kill category used is attrition, which covers those
aircraft with combat damage so extensive that it is neither reasonable nor
economical to repair.
The nuuber of aircraft is reduced by the attrition rate (aircraft/day).
The attrition rate is the product of the sortie rate (sorties per day),
the number of aircraft available (aircraft), and mission survival (fraction
per sortie). The sortie rate varies directly with the fraction of aircraft
remaining. Aircraft available is a function of the number of aircraft and
fraction that are combat ready, which is calculated in Submodel S-1 under
"availability". Mission survival depends on survivability versus air threat
platforms and survivability versus surface threat platforms.
The Attrition Submodel treats Soviet aircraft combat losses in an
identical manner. Again 23 aircraft types have been chosen. The U.S.
aircraft and the U.S.S.R. aircraft were selected to cover a variety of
missions for the different services [24]. The demands of air combat tend
to force distinct designs on aircraft intended for differing tactical roles.
Basically, tactical airpower can be dedivided into two groups: planes
that attack ground targets (attack aircraft and bombers) and those that
engage other airplanes (fighters). Each group can further be divided into
a long- and short-range component.
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‘The three-step process by which aircraft are destroyed by hostile
"hit" and "
ill". The probability
forces in combat is through "detection"
of an aircraft not surviving an encounter is the probability of being
detected multiplied by the probability of being hit if detected multiplied
by the probability of being killed if hit. This convolution of conditional
probabilities has been incorporated into the model for all air-to-air,
surface-to-air, and air-to-surface encounters in the model. Surface-
to-surface interchanges, while important, are beyond the scope of this
research.
SURVIVABILITY ENHANCEMENT TRADE-OFFS
The survivability of an aircraft can be increased by reducing its
susceptibility to being detected and hit by a threat weapon system and/or
by reducing its vulnerability to damage once hit. These provide the base-
line for survival enhancement.
Regarding detection, aircraft--no matter how large~-are small objects
in the vastness of the airspace in which they operate.. Detection reduction
involves reducing the target aircraft signatures (audio, visual, radar and
infrared) that are used by threat systems for acquisition, tracking, and
warhead guidance/homing. Use of minimum engine noise levels, low visibility
paint, low radar cross section, and the shielding or cooling of heat sources
serve these needs. The reduction of these signatures in the model depends
on the size of the "R&D Budget to Detection Denial",
Reduction in the probability of a hit, given detection, can be accom-
plished by reducing the probability of acquisition and/or tracking [28].
Acquisition is the confirmation of enemy aircraft flying a bearing that
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will bring it within weapons’ range. After detection and acquisition, which
may take place in less than a minute, the aircraft must be tracked, visually
or by fire-control radar, and fired upon. These components of the "hit"
process can be frustrated by using deceptors, jammers, expendables, and
warning/tactics. Deceptors fool the radar by sending false signals or
manipulating the signal to make tracking difficult. While the purpose of
deceptors is to degrade tracking capabilities, jammers serve to cause much
shorter detection ranges by burying the actual signal in the noise on the
radar presentation, Expendables, which take the form of chaff, decoys, or
flares, create a signal larger than that of the aircraft causing a fire
control system or a missile guidance system to track it instead of the
aircraft. Warning and tactics refers to the capability of alerting an
aircraft's crew of a threat in time for something to be done to avert it,
Wit susceptibility reduction realized by these four approaches depends on
the amount of R&D funds devoted to these efforts.
The basic vulnerability reduction concepts incorporated into the model
are component redundancy, component hardening, component shielding, and
damage suppression. Component redundancy provides back-up capability in
the event of failure or damage of the primary capability. Hardening refers
to: “vulnerability reduction effects by interposing less essential com
ponents between critical components and the damage mechanisms, by reducing
or eliminating the criticality of components through redesign or reallo-
cation of functions, or by the use of materials having improved character-
istics" [2]. Component shielding refers to the incorporation of armor,
here. The fourth approach, damage suppression, can be achieved by using
damage tolerant inaterials that deform but not shatter, that leak but do
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not rupture, or that suppress fires and explosions. These activities are
supported in the model by the "R&D Budget to Kill Vulnerability Reduction".
In the previous section we alluded to the relative fragileness of
ground air defense weapons. The ability of combat aircraft to protect
themselves is referred to in the literature as “self-defense systems" [2].
The term is used to describe any system which tends to enhance survivability
by providing a real-time method of destroying the threat propagator before
initiation of the damage process. Examples of active self-defense systens
are: (1) a bomber defense missile (BDM) for damage to, or destruction of,
airborne interceptors; and (2) a short-range attack missile (SRAM) for
damage to, or destruction of, surface-based threats. This activity is not
the same as tactics, electronic countermeasures (ECM), electronic counter-
countermeasures (ECCM), etc. which is covered in the model under warning/
tactics, a subset of susceptibility reduction. To model self-defense
systems a detection-hit-kill breakdown was used which describes the air-
craft's capability to destroy hostile weapons through the same process
that the threat confronts the aircraft.
There are six basic acquisition cost and six basic modification cost
"multipliers" in the model that account for survivability enhancement
cost-input tradeoffs between quality measured in survivability terms and
quantity without these enhancements. They are the elements of the matrix
comprised of the detection-hit-kill vector and the reduction-enhancement
vector in each case.
MANAGING TECHNOLOGICAL SUBSTITUTION
one of the great ironies of the civil efficiency/military effective-
nesses mismatch is the contradictory ways in which new technology is viewed
in different environments. Applied in industry it is referred to as pro~
gress; employed in the military it is called "gold plating". American
defense planners have long assumed, properly, that U.S. weaponry must be
technologically superior to the Soviet Union's. Spending on technology
makes sense in our military, just as in the private sector, because it
is typically a substitute for people, and in our society people is a more
valuable resource than capital. Some economy-minded defense reformers have
failed to see the weapons-evolution phenomenon for what it really is--the
same technological substitution trend that is taking place across society.
Waging war is no different in principle from any resource transfor-
mation process, and improvements should be pursued just as vigorously as for
farming, mining, manufacturing and construction. If anything, automation
within the military makes even more sense than in other sectors where human
labor is consumed only figuratively.
PURPOSE OF THE MODEL
How well is the JICG/AS responding to its Charter? Fundamentally, the
JICG/AS is a coordinating group with the responsibility of external coordi-
nation within the Services and among the Services and industry, Equally
important is internal coordination between its Subgroups, to insure mutual
support in the overall goal of survivability advancement and standardization
of methodology to evaluate overall effectiveness of survivability alter-
natives for various aircraft systems and aircraft missions, as required
16
by decision-makers. Even though it is known that the JTCG/AS program has
resulted in direct cost savings during peacetime operations in addition
to the obvious benefits to be realized during a war, there still does not
exist one commonly accepted way of measuring the impact of all survivability
efforts during wartime. It is impossible to compare quantitatively alter—
native projects, efforts, and benefits of resource allocations, making
strategic planning more arbitrary and less rational than is desirable.
There exists a need to develop a coordinating instrumentality, de-
tailing interrelationships for use by the various organizations in the
survivability community in their deliberations on future activities.
‘This modeling effort is directed to the fulfillment of this need,
In order to serve the JTCG/AS in the management of survivability
related activities in the Department of Defense, the model is conceived,
and is being developed, for several interrelated general purposes: tech-
nical evaluation, doctrinal evaluation, force-structure analysis, defense
economy assessment, and for pedagogical uses--all based on survivability
considerations and trade-offs. For the purpose of technical evaluation,
the model is aimed at the weapons’ level--both current and projected com-
ponents and systems; analyses of doctrines and force structure are directed
toward the impact of survivability decisions on tactics and strategy, the
coordination of weapons systems, command, control and communication systems,
and the structure of forces. At the technical level, we are interested in
the relationship between susceptibility and vulnerability reduction and
survivability enhancement. The effect on the number of aircraft required
for different missions would be a typical question for doctrinal evaluation.
Force structure evaluation issues for the model are concerned with problems
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of "product mix"--how many of what aircraft types under survivability
alternatives? All three of the above purposes assume given U.S. and
U.S.S.R. military/economic environments; which, though "given", can still
yield insights into the limits of the problem when ranges of conditions are
selected to create optimistic. and pessimistic alternatives for the future.
USES OF THE MODEL
In fulfilling the above objectives, the model is used to perform
analysis, diagnosis, and operations. Three distinct levels of use may
be identified conforming to the three levels of defense economics described
earlier in the report. ‘The first, for high-level, strategic decision
making, is exemplified by the economic-political-military exercise. It
is the part of the JTCG/AS Model contained in the Economy and Defense
Budget Submodels that is generally accepted as providing the inputs and
constraints to the survivability community. One tempted to question the
need for modeling a level above the survivability decision making respons-
Abilities should devote their attention to Fig. 1, It is evident that
decisions made regarding survivability management affects relative U.S.
and U.S.S.R. force structures and strengths which in time influence govern—
ment and DOD budget allocations that determine survivability funding.
The second-level deals with decisions for which the survivability
community has either complete responsibility or direct input to a higher
echelon. In the model it is incorporated in the Procurement Submodel and
Survivability Submodel. The third-level of model-use addresses itself to
the bureaucratic, operational and scientific activities usually associated
with survivability. It is at the interface of scientific and advisory
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functions with operations--often not concerned with immediate applications
but with building a supply of basic knowledge. It is to be incorporated
into the model by partitioning the Survivability Submodel into Suscept-
ibility and Vulnerability Components, and developing these to a level of
detail consistent with the state-of-the-art and management requirements.
Several figures-of-merits used to define the trade-offs associated
with aircraft design or usage alternatives were discussed in the Surviv-
ability Enhancement Trade-offs Section. ‘Two shortcomings of these para~
meters are the lack of a means for comparing relative strengths and failure
to consider the time dimension. Some of the parameters such as "losses per
target killed" and "number of sorties per aircraft lifetime” address then-
selves to overcoming these shortcomings but do not go far enough and are
seldom used anyway because of the emphasis on cost-effectiveness figures
of-merit required to support or defeat the spending arithmetic of advocacy
models.
Referring to Fig. 1, the "merit rating system" used to generate feed~
back response at the various decision making levels 'ié "Relative Strengths
of U.S.S.R./U.S. Air Power”. Eventually this MRS parameter will combine
several appropriate figures-of-merit, but at present it is limited to two:
(1) "Time After D-Day when Sorties Per Day for U.S, Combat Aircraft Equals
Sorties Per Day for U.S.S.R. Combat Aircraft" and (2) "Time After D-Day When
Total Sorties Flown by U.S. Combat Aircraft Equals Total Sorties Flown by
U.S.S.R. Combat Aircraft" (see Fig. 2). While these two figures-of-merit
are based on the rather conventional sortie rate and sortie capability
FOM's, they are superior because they consider Soviet. air power and are
time sensitive. What is depicted in Fig. 2, is an indication of how long,
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for two different strategies tied to mission survivabilities of .977 and
984, that it would take the U.S. to achieve air superiority as measured
by some weighted average of the two time parameters. Note that in both
cases, the mission survivability probabilities for the average of all U.S.
combat aircraft is higher than the mission survivability probability for
the average of all U.S.S.R. combat aircraft, which is .954. In the next
section the role of scenario generation in the use of the model as suggested
in Fig. 2 will be discussed.
SCENARTO ANALYSTS
Aircraft combat survivability development, design and management is
technological substitution in its purest form. The question is not, is it
good or bad, but how much. We do not believe that this question can be
properly answered using current survivability assessment techniques and
evaluation methodologies. We think that it can be properly addressed using
the JTCG/AS Management Model in one of its many uses.
Both of the super powers are engaged in similar resource allocation
problems in deciding how military spending should be apportioned to R&D,
O&M, and procurement. The allocations are the decision variables used to
influence the inevitable quality/quantity trade-offs in the acquisition
and modernization of their weapons systems, Traditionally the U.S. has
opted for quality and the Soviets, quantity--consistent with their relative
technological capabilities and (some would say) their respective attitudes
‘as to the importance of human life. However, even if the Soviet techno-
logical capability continues to lag that of the U,S. in the future, it is
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20
evident that the range of options available to each side will overlap. How,
then, should each side, go about making its allocation?
In the context of the scenario generated in Fig. 2, we are not saying
that average mission survivability for Soviet combat aircraft is and will
remain .954, for example; we are saying that if it is, and if we choose a
strategy that can be identified as one in which the average mission surviv-
ability of our combat aircraft is .977--a strategy assumed to be available
to us--then we can expect the parameter values shown for the two figures~
of-merit after D-Day. Several other simplifying but not necessarily unreal-
istic assumptions have been made in the scenario analyses summarized in
Fig. 2. First of all, looking at the ordinate axis at time
sees that the inventory of Soviet combat aircraft is one-and-one-half that
of the U.S. Two U.S, strategies are investigated: Strategy 1 in which the
U.S. strives to match Soviet production so as to maintain the status quo in
numbers and in superior survivability (.977 to .954) and Strategy 2 in which
the U.S. acquires less aircraft at an enhanced survivability of .989. At
D-day, under strategy 1 the U.S. has two-thirds the combat aircraft of the
Soviets; under Strategy 2, the U.S, has one-third the combat aircraft of
the Soviets. In preparing for the D-Day showdown all resource inputs are
the same—for the U.S.S.R. and the U.S, under either strategy. Only the
resource allocations have been varied between procurement, O&M, and R&D so
as to produce the relative aircraft quantities and qualities (survivability
probabilities) shown.
What can we conclude from the two scenarios depicted in Fig. 2--
Scenario 1 which pits U.S. Strategy 1 against the U.S.S.R. Strategy and
Scenario 2 which matches U,S. Strategy 2 against the U.S.S.R. Strategy.
au
Assuming that both strategies are within American technological capabilities
(a hardware consideration), which do we choose (a software consideration)?
We believe that the answer to this depends on interpreting the results
in the context of a value system that takes into account the theatre of
operations and national security priorities. It requires extending our
scenarios to include the environments in which these strategies are to
operate.
The common denominator for the U.S. in responding to threats is
control of the air. However, as seen in Fig. 2 the concept of air super-
fority is elusive. Consider U.S. Strategy 1, while after 17 days the
number of sorties per day flown by each side is the same. It is not
until the 48th day that the U.S. catches up to the U.S.S.R. in the total
number of sorties flown--at which time the U.S. sortie rate is approxi-
mately twice the U.8.S.R, sortie rate. For strategy 2, the critical times
are 32 days and 118 days with overwhelming air superiority by the latter
date (assuming the availability of supplies). The ordinate scale in Fig.
2 has been normalized so that aircraft ratios rather than numbers can be
used, making the relationships applicable to different theatre scenarios
where numbers will differ. The point is: what penalty does the U.S. incur
in the time it takes to achieve air superiority and what good does it do
after it has? While the parameter values may be roughly the same in each
theatre-scenario, the answers to these questions will depend upon what is
at stake in each theatre,
789
22
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_--~ RATIO OF NO, OF U.S. COMBAT AIRCRAFT TO HO.
(OF U.S. COMBAT AIRCRAFT WNTIALLY (SCENARIO 1)
RATIO OF NO. OF U.S. COMBAT AIRCRAFT TO NO. OF U.S. COMBE
INTIALLY (SCEMAMO 2)
US.3.A. COMBAT AIRCRAFT SORTIE CAPABLITY-
TTWME AFTER D-DAY WHEN NO. OF U.S. COMBAT AIRCRAFT
EQUALS MO, OF US.S.A. COMBAT AIRCRAFT (SCENARIO 1
“THe AFTER D-DAY WHEN WO. OF US. COMBAT AICRAFT
CaO TRUALS WO. OF USS. COMBAT ABIERAFT
(scemanio 2)
‘THRE AFTER D-DAY WHEM NO, OF US. COMBAT AIRCRAFT
15 THE SAME FOR BOTH SCENARIOS —
"Seats tora sommes ruown ov us.
SSO commer amcrarr semano 2
opay
20 D-60 p420
~ Te —-- pave)
COMBAT AIRCRAFT SURVIVABILITY ENHANCEMENT SCENARIOS
9%
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