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Measuring Military Power
The Soviet Air Threat to Europe
By Joshua M. Epstein
PRINCETON UNIVERSITY PRESSCopyright © 1984 Princeton University Press
All rights reserved.
PROBLEMS OF U.S. TACTICAL AIR FORCE MODERNIZATION
General Trends in Reliability, Maintainability, and Cost
Among the most conspicuous features of technological change is the higher performance of new aerospace weapons. Put simply, "the number of functions required of an individual aircraft has increased from one generation to the next." This trend has been reflected in the increasing complexity of major aircraft subsystems — power plants, navigation sets, weapons control systems, and the like.
The disturbing fact, however, is that as their specified performance and attendant complexity have increased, the reliability of weapon systems has declined. In the words of General Samuel C. Phillips, former commander of the Air Force Systems Command, "Expanding requirements have increased complexity. Growing complexity has increased the number of parts; and as parts and components multiply, the reliability of the system as a whole tends to drop."
This, of course, need not be the case theoretically. Indeed, a designer may increase the parts count, and thus the complexity of a system expressly to raise its reliability, the use of various sorts of redundancy being the most obvious case in point. This and other methods of attempting to bolster reliability have been pursued by the United States. Nonetheless, as the sophistication and complexity of U.S. systems has increased, their reliability has decreased.
More disturbing still, since the 1960s, when the A-7 and F-4 were introduced, "the costs of modern aircraft have increased, in real terms, by a factor of four." This, too, is an empirical relationship and does not mean that increases in cost must reduce reliability as a matter of physical law. But, as a matter of fact, the two have moved in opposite directions. The reliability specified by contract, and assumed in the planning of forces, is, in a great many cases, far higher than the reliability that is actually delivered — actually demonstrated in the field. As one Pentagon study put it, "You can argue, you can threaten, you can cry, you can beg — but once the government is committed to produce the equipment, it is almost impossible to enforce a quantitative reliability requirement."
These general trends in reliability do not, in and of themselves, dictate a decline either in the readiness of U.S. forces or in their capacity to generate and sustain very high numbers of missions per day, or sortie rates, as they are called. Even an extremely unreliable system — one that experiences failure very frequently — may attain very high availability (and activity) if upon failure it can be repaired quickly.
As an everyday illustration of that principle, one's pencil point might break every few minutes; it might have a low "mean time between failures," in the language of reliability theory. But with an electric pencil sharpener (a maintenance system), one has hardly to stop writing at all in order to restore the pencil to peak performance and reenter the fray of composition.
A decline in reliability, then, can in theory be compensated for by a commensurate increase in maintainability. Unfortunately, however, in the U.S. case, the trend is in precisely the opposite direction. As their complexity has risen, the reliability of American systems has decreased, and they have become more difficult to maintain. Among the standard indices of aircraft maintainability in peacetime is mean maintenance manhours per flight hour (MMH/FH). By that measure, the data in Table 1.1 should suggest the overall trend.
Returning to the pencil analogy, there are two corollaries that bear on the Soviets. First, pencils are very inexpensive. Therefore, rather than invest in a sophisticated maintenance "infrastructure" — an electric pencil sharpener — many of us just keep a big mug of pencils on the desk (i.e., near the "theater" of intellectual war). When the pencil we're using wears down, we don't even try to restore it to service. Without lifting our heads from the paper, or breaking our concentration at all, we casually toss the dull pencil aside and pull a presharpened one from the old school mug. As long as pencils remain cheap, that's a perfectly sensible procedure.
By all accounts, the Soviets used to have the same approach to aircraft. They were relatively cheap, and when a plane broke down, it could be set aside too. Rather than attempt to restore it to peak performance right there in the theater of war, the Soviets could simply "plug in" a new plane drawn from their "old school mug": Stalin's defense industry.
But, impelled by technological competition with the West, Soviet aircraft have become increasingly complex; the "pencil" is no longer that cheap. And the Soviets — for a variety of reasons — are turning away from their traditional "old school" solution. Given current costs and complexity, the Soviets cannot simply "throw away" an advanced weapon and bring in a new one every time one breaks down. As we shall see, they are being forced to develop a true maintenance strategy in the Western sense. But they are having a hard time adapting the "old school" institutions — political, economic, and military — to the new requirements.
The second point to bear in mind is that, even granting Soviet weaponry higher reliability (itself open to question), it does not follow that the Soviets enjoy higher availability; that, as noted above, is determined only jointly by reliability and maintainability. As we shall see, there is reason to seriously doubt the ease with which the Soviets can maintain their new advanced weapons.
Within the American trend of increasing overall maintenance manhour requirements, important additional effects are observable. In order to understand these, and as a basis for Soviet-American comparison, the organization of U.S. ground support must be sketched.
Maintenance as well as logistic support for U.S. air forces is conducted at three different maintenance levels (MLs): organizational, intermediate, and depot.
Organizational Maintenance (ML1)
This is maintenance of the flying unit's (the "user organization's") own equipment and is performed by personnel of that organization — hence the name "organizational" maintenance. Tasks would include the inspection, servicing, adjusting, and lubrication of equipment as well as the removal and replacement of parts, minor assemblies, and subassemblies, as indicated by on- and off-aircraft diagnostic and test equipment. "Personnel at this level usually do not repair the removed components, but forward them to the intermediate level," as would be the procedure in the case of any repair falling outside the organization's own capacity. Accordingly, "the least-skilled maintenance men" are utilized at this level. The refueling and rearming of aircraft would normally be performed at ML1. Given the combat requirements for speed in all of the abovementioned "turnaround" operations, organizational maintenance is afforded "minimum time ... for detailed maintenance or diagnostic checkout."
It is very important to note that the rapidity with which organizational ground support can conduct the required maintenance (as well as rearming and refueling) essentially determines the feasible sortie rate. If the so-called "turnaround" can be completed quickly, there will be little time between sorties and a greater number of sorties will be performable per day. Consequently, an aircraft designer charged with the task of ensuring the capability for high sortie rates should "expect to find limited personnel skills and related support at this level and should plan equipment maintenance and servicing requirements accordingly." Accurate field reportage and designer sensitivity to field maintenance problems are therefore essential if technological change is not to outstrip the capacities of ML1 and result in lower than desired sortie levels. Whether or not the Soviet designer has, in fact, been sensitive to that problem is a topic to be discussed at length below.
Intermediate Maintenance (ML2)
Intermediate — or "field" — maintenance is generally performed at fixed installations established to support a number of lower-level (i.e., organizational) maintenance units within some specified geographical area. In the case of carrier-based tactical aircraft, for example, field maintenance is primarily shore-based while organizational maintenance would be conducted on the carrier or other ships in its task force. "Assigned work includes calibrating, repairing, or replacing damaged or unserviceable parts, components, and assemblies, modifying material, and providing technical assistance to user organizations." Intermediate maintenance facilities are staffed by more highly skilled personnel and have a larger complement of more sophisticated test equipment than would be found at ML1. Since maintenance of a more detailed nature is conducted there, it is only natural that rapid turnaround time be less imperative at the intermediate level than at ML1.
Where repair is feasible at ML2, it is conducted on a return-to-user basis. Where it is not, defective equipment is forwarded to the depot level.
Depot Maintenance (D)
Depot level maintenance is conducted at what are essentially industrial facilities. These "are generally located remotely from individual theaters of operation and provide services for several such theaters." The most highly skilled specialists as well as maintenance equipment of extreme bulk and sophistication are available at the depot level, whose tasks would include the complete overhaul, modification, and rebuilding of equipment. Reworking and repair of subsystems and components requiring complex actions would also be conducted here. Occasionally, parts not otherwise available may be fabricated using the depot's extensive shop facilities and expert personnel.
Depot operations are not conducted on a return-to-user basis. Rather, repaired components and other depot products are returned to the theater supply systems from which they came.
In contrast to this three-tiered American structure, the Soviet system is essentially two-tiered, and lacks a comparable intermediate (ML2) "cushion" between the critical flightline (ML1, where the wartime turnaround must be accomplished quickly) and the remote depot (where time-consuming industrial queues await the damaged plane). Therefore, in the Soviet case, if its maintenance problems outstrip the skills and equipment available at the organizational level (in their case, the Air Regiment), the aircraft — if it is to return to combat at all — will have to return via depot, and may not see action for a very long time.
In order to estimate the Soviet Air Regiment's capacity to generate and sustain high wartime sortie rates (missions per day), it will be necessary to gauge its adjustability to technological advance. As a basis for that estimate, some important additional effects of modernization should be noted on the American side.
As shown in Table 1.1 above, aggregate maintenance man-hours per flight hour (MMH/FH) has increased; the sum of the organizational, intermediate, and depot values has risen. Equally important for our purposes, MMH/FH has risen "at each maintenance level." Again, in theory this need not be the case. Modernization could, for example, have resulted in an increase in MMH/FH at ML1 alone: malfunctions of the type organizational maintenance is designed to handle could simply have increased in frequency. Had this been the only effect, aggregate MMH/FH (ML1 + ML2 + D) would have risen, as observed, but without increasing MMH/FH at either the intermediate or depot levels. In fact, however, not only have "ML1-type" malfunctions increased in frequency but maintenance tasks beyond organizational capabilities have expanded as well. Nor has an increase in MMH/FH at ML2 succeeded in containing the problems, which have overflowed to swell the demand for depot-level resources as well.
Indeed, and this is the second point, modernization, while producing across-the-board increases, has dramatically altered the pattern in which the total maintenance burden is distributed among America's three maintenance echelons. For example, the aggregate MMH/FH for the relatively simple A-7E is 24.01. Of this total, 69 percent (or 16.58 MMH/FH) is conducted at the organizational level, with depot MMH/FH representing only 14 percent (or 3.36 MMH/FH). By contrast, of the total of 59.97 MMH/FH absorbed by the highly sophisticated F-14A, organizational capabilities can accommodate only 52.6 percent (31.57 MMH/FH) while depot work as a percentage of the total is 29.3 percent (17.57 MMH/FH). Depot requirements, then, as a percentage of the aggregate, are more than twice as high for the F-14A as they are for the A-7E. And, it should be noted, the actual depot MMH/FH demanded by the F-14A (17.57), in absolute terms, is over five times the corresponding figure for the A-7E (3.36).
Rising complexity, then, has not only increased the sheer volume of maintenance required (per flight hour) at each maintenance level, but it has sharply increased the demand for higher skills — notably, depot skills — as a proportion of that rising total. As will become evident, the Soviets are facing similar problems.
Merely as a rough indicator of the associated costs on the U.S. side, it is worth noting that in outlays, Operations and Maintenance (O&M) has repeatedly overshadowed every other appropriations title in the Air Force budget. Nor is that situation unique to the Air Force. In outlays, over the entire defense budget, O&M exceeded every other title in fiscal years 1975 through 1981, and has since been outweighed only by the procurement account. At well over 40 billion dollars per annum since fiscal year 1980, operations and maintenance of military equipment is, in fact, a national priority. More sobering still, O&M figures systematically underestimate certain real costs of unreliability and equipment maintenance because many of the budget's non-O&M lines (e.g., personnel, RDT&E, procurement, and military construction) contain very substantial expenditures directed at reliability and maintenance problems.
The costs, in short, are staggering. What are the benefits? What, for example, is the readiness of U.S. equipment?
Readiness of Equipment
A readiness rating system seeks to register unit capabilities to carry out assigned missions. Since weapon systems are "man-machine" systems, the assessment of unit readiness perforce includes judgments about the capabilities of personnel to perform their assigned functions. While it is generally agreed that personnel readiness depends upon training, flight time, the realism of exercises, and other factors, there is no general law relating these to actual wartime performance. Any assessment of combat readiness thus faces uncertainties concerning the readiness of people. While there is uncertainty concerning material readiness as well, it is clear that if only fifty percent of a unit's weapons are ready, then no more than fifty percent of the unit will be, even if one hundred percent of its people are. Current readiness of fully combat-equipped aircraft, then, while it is only part of any overall readiness status, represents an important upper bound on unit readiness. It is here, in the area of material readiness, that the reliability-maintainability problems reviewed above are most clearly in evidence.
As complexity has increased, reliability has generally declined. At the same time, no compensating increase in maintainability has been forthcoming, despite vast expenditures. Predictably, the net result has been a general decline in readiness as suggested in Table 1.2. In order to draw reasonable inferences about the Soviets, it is critical to interpret these data correctly. While a troubling inverse relationship between American complexity and readiness is clear, there is a fundamental distinction that is missed by most of the popular horror stories about American readiness.
The basic question is this: for planning purposes (or for purposes of threat assessment), does one define readiness merely as the force that can be put in the field; is it just initial deployability? Or should one build in to one's definition, and readiness rating system, some checks that the force can be kept in the field long enough to execute its assigned mission? Surely, it only confuses matters to measure American readiness against the latter, more demanding standard and then compare it against Soviet "readiness," defined merely as the initially deployable force. In order to avoid that very common error, the meaning of these "Not Mission Capable" data should be clarified.
Excerpted from Measuring Military Power by Joshua M. Epstein. Copyright © 1984 Princeton University Press. Excerpted by permission of PRINCETON UNIVERSITY PRESS.
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