In this month’s special section, we survey the posture of theater airpower today and look ahead to the changes in store between now and the end of the century. By all accounts, the performance gains in the next generation of tactical weapons will be spectacular — in speed, range, accuracy, power, and more.
Less attention-grabbing but perhaps just as important to the actual combat punch delivered will be the remarkable advancements seen in “the ilities.” One of the most significant characteristics of US military thinking in the 1980s is emphasis on the readiness and sustainability of forces and on the reliability and maintainability of weapon systems. There has always been some concern for “the ilities,” as they used to be called but too often they have played a weak second fiddle to other considerations. By contrast, today’s force planner is inclined to think less about numbers of aircraft on the ramp and more about the number of sorties that can be put in the air.
There are numerous indications that the Pentagon is serious about this change in priorities. The Air force has already announced that it will appoint an assistant secretary for readiness and support this year. It had said previously that, in awarding contracts, it intended to give reliability and maintainability equal weight with the traditional source-selection factors of cost, schedule, and performance. In an increasing number of cases, the Air Force has passed over low bidders to buy from vendors who were stronger on reliability and maintainability.
The motivation to improve system reliability is compelling. Maintenance consumes more man-hours than almost anything else the Air Force does. Twenty-eight percent of the enlisted force and some 4,000 officers are assigned directly to maintenance specialties. An Appreciable number of others, from wing commanders to supply people, work on maintenance-related matters at least part of the time. Maintenance is expensive in terms of personnel, spare parts, repair facilities and equipment, and other support costs, including airlift. The Air Force estimates that if it could double the reliability of spare parts for the tactical fleet, it could buy up to four squadrons’ worth of new F-16 fighters with the savings. And since the military-age population of the United States is declining, it becomes imperative to find better ways to accomplish labor-intensive functions.
For the next few years, the combat posture of the fore will likely depend, even more than it does now, on the quality of maintenance and the reliability of the systems maintained. Aircraft procurement has tailed off for budgetary reasons, and funding is down for readiness and sustainability. It is essential that theater squadrons be able to generate and regenerate sorties with the aircraft they have on hand.
Fortunately, in-service rates are high for USAF’s newer aircraft. The reliability of airborne components is better than ever, and combat systems have become progressively easier to maintain. A leading example of the trend is the F-16 fighter, which requires only about half the maintenance man-hours per flying hour that the older F-4 does. The best news of all is that the biggest gains in reliability are yet to come.
Donald C. Latham, Assistant Secretary of Defense for C3I, popped a few eyeballs at AFA’s recent tactical warfare symposium when he said that the Air Force hopes to achieve a Mean Time Between Failure (MTBF) of 10,000 hours with the avionics in its next fighter aircraft. If that sounds farfetched, consider the improvements seen already. A new digital scan converter for B-52 bombers, for instance, is guaranteed by the manufacturer to go 4,000 flying hours between repairs. It replaces a unit that needed work every 230 hours. The new one also costs less.
The trend is so strong that the Air Force now believes it has been too timid in setting reliability specifications. Systems — particularly electronic systems — usually last much longer in actual use than the contract prescribed. Major commands have been told that when specifying requirements for new systems, they should insist on at least double the reliability and half the maintenance of predecessor systems.
Moreover, the minimum acceptable MTBF for avionics line-replaceable units is now 2,000 hours. With 2,000-hour reliability, a wing ought to average only one LRU failure a month in peacetime. In combat, it would mean a ninety percent chance that any given LRU would make it through the first thirty days of fighter operations without failure. In an aircraft with twenty-five LRUs, there would be a ninety percent probability that none of them would fail for a couple of days.
The Air Force has also ordered, “environmental stress screening” — a regimen of thermal and vibration testing — to find weak or faulty electronic components before they leave the factory. This “shake and bake” process, it hopes, will reduce the rate of defective parts to one in 1,000 in FY ’87 and to one in 10,000 by FY ’90.
Greater reliability does not always mean higher cost, but when it does, the expense is usually a good investment. Class “S” parts for the Inertial Upper Stage cost $24 million, compared to $1.1 million for class “B” parts. Testing, however indicated that the lower-quality parts would have sixty times as many failures, leading to an additional cost of $100 million over the life of the system. The tradeoff penalties to achieve reliability are no longer as sever as they once were. The technologies that underlie reliability — very-high-speed integrated circuits foremost among them — are the same ones that lead to many of the major gains in system performance.
The frontiers of reliability are not yet closed. Most of the dramatic gains so far have been in the area of electronic systems. There are certain to be breakthroughs in other kinds of systems across the board, and the sooner the better. Should the United States find itself engaged in war again, the outcome could well rest on the once-neglected ilities.
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