of Mach 2.2 can be reached. The first YF-16 made an unscheduled first flight on January 20 at Edwards Air Force Base, Calif. G.R. Some statistics on air transportation of hazardous materials in the U.S. is given. The Hazardous Materials Regulations concerning the air transport of explosives, flammable solids, poisons, radioactive materials, and etiological agents with background information and classification systems are reviewed, with attention to restrictions. V.Z. A74-21726 The Fairchild Industries A-10 Designed for close air support. J. P. Geddes. Interavia, vol. 29, Feb. 1974, p. 119-122. As a result of the experience provided by the war in Vietnam and of studies concerning the situation in Europe, prototypes of an aircraft for close air support were built. On Jan. 18, 1973 it was announced that Fairchild's A-10 had won the competition. A contract for ten preproduction aircraft was awarded and preparatory steps leading to the production of 600 A-10s beginning in 1975 were considered. Details of A-10 aircraft design are discussed together with aspects of the A-10 systems, questions of survivability, maintenance considerations, and problems of procurement. A74-22145 G.R. Reliability assurance of individual semiconductor components. R. F. Haythornthwaite, A. R. Molozzi, and D. V. Sulway (Department of Communications, Communications Research Centre, Ottawa, Canada). IEEE, Proceedings, vol. 62, Feb. 1974, p. 260-273. 46 refs. Where small numbers of highly reliable semiconductor devices are required, conventional methods of procurement are found to have deficiencies. An approach to procurement is proposed which is cost effective, accommodates new device types, and assures reliability in the individual device. Although principally applied to silicon planar transistors, the approach can be extended to other semiconductor types. A critical evaluation is made of the manufacturer and his technology. The devices obtained from each diffused wafer are grouped into separate lots. Selected tests are performed on these lots in order to discover possible failure mechanisms. Tests may involve simple electrical measurements or detailed techniques such as scanning electron microscopy and X-ray microprobe analysis. The Canadian/U.S.A. Communications Technology Satellite (CTS) program has adopted this procurement procedure. (Author) A74-22189 # Earth resources satellites The interest for European industry. J. Plevin (ESRO, Space Applications Div., Neuilly-sur-Seine, Hauts-de-Seine, France). (European Space Symposium on International Collaboration in Space, 13th, London, England, June 25-27, 1973.) British Interplanetary Society, Journal, vol. 27, Mar. 1974, p. 161-172. 11 refs. In order for the European earth scientist community to take large-scale advantage of earth satellites in geophysical studies, it will be necessary to overcome many problems. In Europe, the more sophisticated remote sensing systems are unavailable, except to military programs. Industry would have to provide vast software support, which would involve risky capital investments unless a program were conducted at a government, and most likely, international level. As earth scientists would generally not be familiar with the operation of the remote sensing equipment, interdisciplinary cooperation would have to be fostered. A preparatory program centered around aircraft equipped with remote sensing instruments is suggested. P.T.H. A74-22640 # Air transportation of hazardous materials. A. C. Bensmiller (U.S. Department of Transportation, Transportation Safety Institute, Washington, D.C.). In: Economics of air safety and long-range safety research and development; Proceedings of the Twenty-sixth Annual International Air Safety Seminar, Lisbon, Portugal, November 4-7, 1973. Arlington, Va., Flight Safety Foundation, Inc., 1973, p. 198-202. A74-22686 # International user charges and their impact on world-wide implementation of ATC systems. D. A. Lewis (International Air Transport Association, Montreal, Canada). In: Upgrading the ATC system; Proceedings of the Annual Meeting, Washington, D.C., November 28, 29, 1973. Washington, D.C., Radio Technical Commission for Aeronautics, 1973. 6 p. A74-22687 # In the broadest sense the term 'user charges' includes landing fees, fuel taxes and charges, passenger charges paid by airlines, and en route charges. En route charges are the fastest growing of all and cover fees for en route navigation, communication, air traffic control, and meteorological, and search and rescue facilities and services. Aspects of the rapid escalation of the costs of the charges are discussed together with the reasons for this escalation and the effects of it. G.R. A74-23548 Joint service agreements A need for consolidation. D. P. Cannon (U.S. Naval Material Command, Naval Air Development Center, Warminster, Pa.) and W. J. Hock (USAF, Life Support System Program Office, Wright Patterson AFB, Ohio). In: Survival and Flight Equipment Association, Annual Symposium, 11th, Phoenix, Ariz., October 7-11, 1973, Proceedings. Canoga Park, Calif., Survival and Flight Equipment Association, 1974, p. 108, 109. Review of the background and present status of the new management concept of joint service effort and cooperation in the area of life support equipment and facilities. Efforts have been made to identify and study organizational functions and facilities, capabili ties, and capacities in areas of life-support equipment research, development, test, evaluation, and logistics, where consolidation or combined management arrangements could yield a high payoff. These efforts have so far resulted in the Air Force being selected for the management of survival avionics and pressure suits, the Army being assigned body armor, and the Navy taking charge of flotation equipment and antiexposure clothing. M.V.E. Constraints on military budgets in the face of mounting operation and maintenance costs have prompted a search for additional methods of cost reduction. This paper describes an investigation into the use of warranties as a means of making the vendor more responsible for field performance, thus motivating him to produce reliable equipment and introduce improvements as necessary. A life-cycle-cost model is described and used to examine the relative economic advantages of warranty versus nonwarranty purchases. The major conclusions reached are that a properly constituted and applied warranty can yield significant reliability and life-cycle-cost benefits and that broader use of yarranties in military avionics procurement is advisable. (Author) A74-20968 Reliability growth - Actual versus predicted. C. N. Stoll and W. S. Oliveri (Raytheon Co., Electromagnetic Systems Div., Goleta, Calif.). In: Annual Reliability and Maintainability Symposium, Los Angeles, Calif., January 29-31, 1974, Proceedings. New York, Institute of Electrical and Electronics Engineers, Inc., 1974, p. 391-395. Evaluation of a number of case histories of sudden unexpected decreases in device reliability, observed contrary to normal predictions in such standard, mature products as power wirewound resistors, high-voltage triodes, pulse transformers, and bandpass filters. The failure causes involved are discussed, along with the necessary corrective action. M.V.E. A74-20969 DC-10 avionics parts reliability in review. R. S. Babin (Douglas Aircraft Co., Long Beach, Calif.). In: Annual Reliability and Maintainability Symposium, Los Angeles, Calif., January 29-31, 1974, Proceedings. New York, Institute of Electrical and Electronics Engineers, Inc., 1974, p. 403-408. The McDonnell Douglas DC-10 aircraft program has demonstrated the effectiveness of a number of reliability and quality engineering controls and disciplines. Notable among them are several key controls on electrical, electronic, and electromagnetic parts in the avionics systems. A qualitative review of those parts controls is presented, utilizing DC-10 case histories (actual part-failure problems) as a basis for discussion and evaluation of the relative effectiveness of the controls. The controls that have shown most room for improvement, judged by the impact of their deficiencies on fielded equipment reliability, are: (1) part-failure reporting, analysis, and corrective action, (2) multiple-source part procurement, and (3) the designation and control of microcircuit part quality. A74-20970 (Author) Time series modeling. P. B. Robinson (AT & T, New York, N.Y.) and A. P. Stamboulis (New York, Polytechnic Institute, Brooklyn, N.Y.). In: Annual Reliability and Maintainability Symposium, Los Angeles, Calif., January 29-31, 1974, Proceedings. New York, Institute of Electrical and Electronics Engineers, Inc., 1974, p. 413-419. 12 refs. A sequence of component failures or a stream of investment returns may quite conceivably possess significant serial correlation. Preference orderings among alternative investments or system configurations, then, will be heavily dependent on the time series structure of the observable process as well as the levels of its autoregressive parameters. Here, we concentrate on the latter problem. A new detection statistic for the autoregressive parameter of a first order autoregressive process is developed. Its power is shown to be comparable to that of the Durbin-Watson Statistics for the model considered. Moreover, it is related to a two-sample moving range statistic. As such, it is easy to chart and easily understood by practioners of quality control. (Author) Management teams are required to make several key decisions during the conceptual phase of a project. Analytical prediction techniques aid the decision maker by providing timely insight into the availability and consequences of alternates. This paper describes the application of a computer code entitled PROSIM (PROject SIMulation) as a project planning prediction technique. PROSIM uses a Monte Carlo simulation to evaluate the impact of alternate system design concepts and associated procurement and operating strategies on system operation and cost. This technique has been used successfully and has demonstrated its capability to meet stringent requirements for realism. The specific types of problems amenable to evaluation with PROSIM are presented, and the capabilities and mechanization of the code are discussed. A sample problem is described to show how PROSIM is used to translate the statement of the decision variables into output displays that facilitate decision making. T.M. A74-20987 Risk analysis A program management tool. J. D. Gault (Boeing Co., Wichita, Kan.). In: Annual Reliability and Maintainability Symposium, Los Angeles, Calif., January 29-31, 1974, Proceedings. New York, Institute of Electrical and Electronics Engineers, Inc., 1974, p. 548-551. Investigation of the adaptability of risk analysis methodology to evolutionary situations such as environmental problems. Techniques presently used to evaluate airplane fatigue risks are shown to be applicable to any situation having an inherent risk which increases with time but may be countered by periodic application of corrective measures. Control of our environment, mass transportation and consumer protection are among the problems that fall into tr category. The investigation results indicate that risk analysis provi an approximate answer to the right problem by tying together interrelated influences in a complex system. A74-21013 Microbiological standards for frozen to D. Appleman (Southern California, University, Los Angeles, M. D. Appleman, Jr. (Southern California Permanent Group, Bellflower, Calif.), and M. D. Appleman. In: Cry gases: Testing methods and standards development; Proce the Symposium, Los Angeles, Calif., June 25-30, 1972 Philadelphia, Pa., American Society for Testing an Materials, 1973, p. 3-11. 16 refs. Factors predetermining quality and safety of frozen los products are discussed along with different types of standa Attention is drawn to the fact that microbiological standard frozen foods must be studied thoroughly prior to establishment sources and methods of transmission of diseases through the of frozen foods and methods of evaluating and minimizing r clarified. The inherent inconvenience and danger of estab microbiological standards for foods without careful techniques are explaid. The impact of microbiological st for foods upon incip or frank spoilage is discussed. of Mach 2.2 can be reached. The first YF-16 made an unscheduled first flight on January 20 at Edwards Air Force Base, Cairt G A74-21726 The Fairchild Industries A-10 - Designer to close air support. J. P. Geddes. Interavia, vol. 29, Feb 192: 119-122. As a result of the experience provided by the war er Vietna and of studies concerning the situation in Europe, prototype e aircraft for close air support were built. On Jan. 18 19 announced that Fairchild's A-10 had won the competition contract for ten preproduction aircraft was awarded and precator steps leading to the production of 600 A-10s beginning in 1975 we considered. Details of A-10 aircraft design are discusser 10 with aspects of the A-10 systems, questions of survab maintenance considerations, and problems of procurement A74-22145 Reliability assurance of individual em ductor components. R. F. Haythornthwarte, AR Mor V. Sulway (Department of Communications, Communicatio search Centre, Ottawa, Canada). IEEE, Proceeding: £ 1974, p. 260-273. 46 refs. Where small numbers of highly reliable semiconduc are required, conventional methods of procuremen have deficiencies. An approach to procurement is propose cost effective, accommodates new device types an liability in the individual device. Although pri silicon planar transistors, the approach can be externe semiconductor types. A critical evaluation is made turer and his technology. The devices obtamer tror eac wafer are grouped into separate lots. Selected test a these lots in order to discover possible failure meca involve simple electrical measurements or detaler sens scanning electron microscopy and X-ray microDE Canadian/U.S.A. Communications Technology Sass gram has adopted this procurement procedure Metallic Air Vehicle Structure AAF, Flight Dynamics Laboratory, and C. E. Hart (General Dynamics Fort Worth, Tex.). AIAA, ASME, and Dynamics and Materials Conference, 17-19, 1974, AIAA Paper 74-336. 11 p. rs, $2.00. or Air Vehicle Structure Program offers an trate potential increases in the reliability, of future Air Force Weapon Systems by the demerging structures, material and manuduring the design and development of a wing re Program objectives and accomplishments are nagement methods and concepts found to be of am manager are highlighted. Each phase of the a preliminary design, detail design, fabrication, and Un some detail. Emphasis is placed on the use of ring the design phase and the extensive development ecessary to provide information for the detail design turing phases. (Author) 683 # The growing procedural problems of washing moth aircraft. H. J. Singletary (Lockheed-Georgia Co., Marietta, AIAA, ASME, and SAE, Structures, Structural Dynamics and Aerials Conference, 15th, Las Vegas, Nev., Apr. 17-19, 1974, 1 AA Paper 74-376. 3 p. Members, $1.50; nonmembers, $2.00. Jumbo jets, like supertankers, are designed to carry larger payloads at less operational cost; yet many benefits can be challenged because of the magnitude of ground service requirements. The author discusses the efforts in progress today to overcome a major ground time consumer: aircraft cleaning. He focuses on the problems of available cleaning materials, equipment, and facilities as they relate to materials of construction in wide-bodied aircraft and to the environments which affect the cleaning capability/application of current technology. Whereas the author recommends an approach to a resolution, he expresses an opinion that many affected organizations have treated the subject of washing like fleas. They do little more than scratch. (Author) European industry. J. Plevin (ESRO S Neuilly-sur-Seine, Hauts-de-Seine, France, Ere sium on International Collaboration r England, June 25-27, 1973.) British Imerpan vol. 27, Mar. 1974, p. 161-172. 11 refs In order for the European earth scien large-scale advantage of earth satellites in be necessary to overcome many prob sophisticated remote sensing system military programs. Industry would support, which would involve rok program were conducted at a gove tional level. As earth scientists w the operation of the remote cooperation would have to centered around aircraft equ suggested. # A74-26874 Confidence assessment of military airframe cost predictions. D. P. Tihansky (RAND Corp., Santa Monica, Calif.). Operations Research Society of America and Institute of Management Sciences, Joint National Meeting, Boston, Mass., Apr. 22-24, 1974, Paper. 30 p. 21 refs. Analysis of the degree of confidence that can be placed in cost predictions for airframes from standard cost models. Each airframe cost observation is partitioned into six components based on phases of the development or production cycle e.g., flight test costs and manufacturing labor wages. Confidence measures are then compared for alternate model forms and for the use of a single regression on total costs versus the aggregation of regressions on component costs. Statistical theory is developed to test the independence of component models and to estimate predictive statistics for aggregated cost estimates. (Author) A74-23549 Integrated logistics support and acquisition management /ILS-AM/ panel for aviation-crew systems equipment changes. R. Gilles and J. Harding (U.S. Naval Material Command, Naval Air Development Center, Warminster, Pa.). In: Survival and Flight Equipment Association, Annual Symposium, 11th. Phoenix, Ariz., October 7-11, 1973, Proceedings. Canoga Park, Calif., Survival and Flight Equipment Association, 1974, p. 110, 111. The purpose of the ILS/AM panel is to coordinate the various logistic support aspects of implementing changes in certain survival, safety, and personal equipment used by Naval aircrews. It consists of representation from advisory, operational, and implementation activities. The advisory portion is staffed in part by representatives from the Office of the Chief of Naval Operations and from the Naval Air Systems Command. P.T.H. A74-23596 A status summary of the MRCA project. G. Madelung (Panavia Aircraft GmbH, Munich, West Germany). Aeronautical Journal, vol. 77, Dec. 1973, p. 606-611. The air intakes of the multirole combat aircraft (MRCA) are forward of the wing, and their duct is remarkably straight, minimizing boundary layer effects and distortion. Two interfaces are of particular basic interest: the compatibility of the air intake with the engine, and the afterbody-nozzle shaping together with the thrust reverser. The after fuselage-nozzle combination was analyzed and tested in the wind tunnel to arrive at a proper design tradeoff between base drag, thrust, and weight. The early prototype aircraft will concentrate on handling, propulsion, structural leads, performance, and general subsystems. The later prototypes will do avionics system and external stores work. F.R.L. A74-23597 The determination of realistic probability levels for project completion dates. G. Mitchell and M. J. Willis. Aeronautical Journal, vol. 77, Dec. 1973, p. 620-625. 6 refs. It is considered useful to estimate a probability function of completing a project by a specified date in order that more realistic planning can be executed. Attention is given to network analysis, the activity, the probability distribution of activity duration, determination of subcritical path, and the Monte Carlo simulation for computing the completion date distribution. Planning the project pessimistically and planning it optimistically, optimization of the project network, and estimation of realistic probabilities are discussed. F.R.L. A74-23600 A study is conducted of the relative effectiveness and cost of research employees recruited from four different sources for fulltime employment at the Langley Research Center of NASA. Particular attention is given to employees recruited for professional scientific and engineering positions requiring aerospace technology qualifications. The recruitment methods are discussed together with the compensation level and the performance criteria. G.R. A74-23877 The Aeritalia-Lockheed agreement The package also includes the Lancer (L'accordo Aeritalia-Lockheed - Nel pacchetto c'è pure il Lancer). I. Coggi. Aviazione di Linea, Difesa, e Spazio, vol. 12, Feb. 1974, p. 58-60. In Italian. Consideration of the implications of an agreement concluded recently concerning collaboration between Italian and U.S. firms with regard to marketing of the G-222 military transport and the F-104 supersonic fighter (the Starfighter) and production of a successor to this fighter called the Lancer. Certain discrepancies between the Italian and U.S. communiqués issued following the agreement are noted, giving rise to the conclusion that production of the Lancer is contingent on successful marketing of the G-222 and the F-104. A detailed description is given of the characteristics of the Lancer, showing how it maintains many of the characteristics of the F-104, while achieving improved maneuverability and eliminating the pitchup phenomenon typical of the Starfighter. A.B.K. A74-24961 Astrononautical research 1972; Proceedings of the Twenty-third Congress, Vienna, Austria, October 8-15, 1972. Congress sponsored by the International Astronautical Federation. Edited by L. G. Napolitano, P. Contensou, and W. F. Hilton. Dordrecht, D. Reidel Publishing Co., 1973. 366 p. $39.45. Recent advances in space science and technology are described by papers dealing with basic problems in astrodynamics and bioastronautics, the engineering and management aspects of space technology, space applications in a variety of disciplines, and scientific activities conducted by students at universities. Some specific topics include the theory of spacecraft motion in a noncentral gravitational field, spacecraft wash-water recovery, contamination of the spacecraft atmosphere by carbon monoxide, performance evaluation of dual (mixed) propellant vehicles, spacecraft stability to pogo vibrations, developments in remote sensing applications, materials processing in a zero-gravity environment, use of the finite element method for aerospace structures, and Mercury orbit trajectories. A74-25357 # T.M. The new constraints on military aircraft (Les nouvelles contraintes de l'aéronautique militaire). J. Soissons. Association Aéronautique et Astronautique de France and Union Syndicale des Industries Aéronautiques et Spatiales, Congrès International Aéronautique, 11th, Ecole Nationale Supérieure de Techniques Avancées, Paris, France, May 21-23, 1973, Paper. 12 p. In French. A clause that appears regularly at the end of military aircraft specifications, requiring the new weapon system to be 'robust, low-cost, and easy to maintain' is studied in the light of the constraints imposed on the design, development, and manufacture of new generation military aircraft by current economic trends, fiscal policy, and rapidly increasing cost of advanced materials and technological sophistication. Some aspects of possible tradeoffs between costs and sophistication are examined. A74-25388 V.P. User needs and applications for remote sensing. W. T. Talbot (McDonnell Douglas Astronautics Co., Huntington Beach, Calif.). In: Remote sensing of earth resources; Proceedings of the Second Conference on Earth Resources Observation and Information Analysis System, Tullahoma, Tenn., March 26-28, 1973. Volume 2. Tullahoma, Tenn., F. Shahrokhi, University of Tennessee, 1973, p. 39-56. This paper describes an attempt to improve upon existing techniques and capabilities for assessing critical national problems. It is a beginning, among others, of an attempt to develop a logical approach and methodology for breaking down problems into definitive organizational roles for resolution, and for translating assigned charter responsibilities into investigation requirements and information needs for remote sensing system applications. By integrating each critical national problem with the assigned character responsibilities and objectives of various Government agencies, key problem effects on agency activity can be defined and, from these, basic problem investigation issues and questions for formulating information requirements. (Author) Information Analysis System, Tullahoma, Tenn., March 26-28, 1973. A74-25398 Automated approach to the biological survey for pest management systems. P. D. Fisher, R. H. Caron, R. L. Walton, and D. L. Haynes (Michigan State University, East Lansing, Mich.). In: Remote sensing of earth resources; Proceedings of the Second Conference on Earth Resources Observation and Information Analysis System, Tullahoma, Tenn., March 26-28, 1973. Volume 2. Tullahoma, Tenn., F. Shahrokhi, University of Tennessee, 1973, p. 227-247. 12 refs. Research supported by the Michigan State University; NSF Grant No. GI-20. An approach to pest insect management is shown. Through this approach multifactor control strategies can be systematically developed and modified from region to region according to day to day changes in weather, field, and economic factors. A method for a biological survey which is compatible with this approach to pest insect management is presented. The basic approaches for gathering the required data are described along with details concerning the hardware required for retrieving, storing and processing the raw data. Problems associated with data management and pattern recognition are discussed. An efficient algorithm for performing object isolation in an image plane is also presented and applied to three representative images. A74-26416 G.R. MRCA prepares for flight test. Flight International, vol. 105, Mar. 28, 1974, p. 395-399. The multirole combat aircraft (MRCA) flight test program is the most comprehensive yet undertaken for any European military aircraft. Nine prototype and six preproduction MRCAS will take part in a closely integrated test schedule. Only in the later stages will this diverge to investigate the special requirements and equipment, particularly weapons, of Britain, West Germany, and Italy. The MRCA flight trials will be supported by a number of 'hack' aircraft equipped to investigate particular aspects in isolation from the main program. F.R.L. A74-26651 # Advanced Metallic Air Vehicle Structure Program. F. D. Boensch (USAF, Flight Dynamics Laboratory, Wright-Patterson AFB, Ohio) and C. E. Hart (General Dynamics Corp., Convair Aerospace Div., Fort Worth, Tex.). A/AA, ASME, and SAE, Structures, Structural Dynamics and Materials Conference, 15th, Las Vegas, Nev., Apr. 17-19, 1974, AIAA Paper 74-336. 11 p. Members, $1.50; nonmembers, $2.00. The Advanced Metallic Air Vehicle Structure Program offers an opportunity to demonstrate potential increases in the reliability, integrity and efficiency of future Air Force Weapon Systems by the integration of new and emerging structures, material and manufacturing technologies during the design and development of a wing carry through structure. Program objectives and accomplishments are described briefly. Management methods and concepts found to be of value to the program manager are highlighted. Each phase of the program including preliminary design, detail design, fabrication, and test is described in some detail. Emphasis is placed on the use of trade studies during the design phase and the extensive development test program necessary to provide information for the detail design and manufacturing phases. (Author) A74-26683 # Jumbo jets, like supertankers, are designed to carry larger payloads at less operational cost; yet many benefits can be challenged because of the magnitude of ground service requirements. The author discusses the efforts in progress today to overcome a major ground time consumer: aircraft cleaning. He focuses on the problems of available cleaning materials, equipment, and facilities as they relate to materials of construction in wide-bodied aircraft and to the environments which affect the cleaning capability/application of current technology. Whereas the author recommends an approach to a resolution, he expresses an opinion that many affected organizations have treated the subject of washing like fleas. They do little more than scratch. (Author) A74-26471 # The Soviet-American space experiment (Sovetsko-Amerikanskii kosmicheskii eksperiment). K. B. Bushuev. Akademiia Nauk SSSR, Vestnik, Jan. 1974, p. 59-66. In Russian. Brief survey of the history, current state, and goals of the joint Soviet-American space laboratory program planned to begin with a rendezvous of a Soviet Soiuz spacecraft and an American Apollo spacecraft in 1975. The organizational and technological aspects of the program are discussed. Some details are given on the projected space experiments. A74-26567 V.Z. The development of the WG-13. A. H. Smith (Westland Helicopters, Ltd., Yeovil, Somerset, England). Aeronautical Journal, vol. 78, Jan. 1974, p. 23-31. The conception of the initial program for the aircraft is considered together with the management and development of this program. A completely rationalized overall program was completed by December of 1967. Two major changes to the program took place during the year 1969. The early months of 1971 saw the final preparation of the first basic aircraft for flight. Some aspects of development testing are discussed together with questions of flight testing and manufacture. G.R. A74-26874 # Confidence assessment of military airframe cost predictions. D. P. Tihansky (RAND Corp., Santa Monica, Calif.). Operations Research Society of America and Institute of Management Sciences, Joint National Meeting, Boston, Mass., Apr. 22-24, 1974, Paper. 30 p. 21 refs. Analysis of the degree of confidence that can be placed in cost predictions for airframes from standard cost models. Each airframe cost observation is partitioned into six components based on phases of the development or production cycle e.g., flight test costs and manufacturing labor wages. Confidence measures are then compared for alternate model forms and for the use of a single regression on total costs versus the aggregation of regressions on component costs. Statistical theory is developed to test the independence of component models and to estimate predictive statistics for aggregated (Author) cost estimates. |