1、 . .II_ . SAE AIRx1937 8b R 8357340 0007128 1 M 6 . 6.1 6.2 6.3 6.4 6.5 6; 6 6.7 6.8 6.9 6.10 7 . 7.1 7.2 7.3 7.4 7.5 8 . 8.1 8.2 8.3 8.4 8.5 9 . 9.1 9.2 1 o . 1 o . 10.2 10.3 10.4 -2- TABLE OF CONTENTS Contd . Section IhPUT . General Description of the Project System Parameters . Engine Design and
2、Development Requirements Fleet Size and Structure Overall Timescales and Del i very Schedules . Fleet Utilization . Maintenance Organization Maintenance Demands . Spares Requirements . Cost Basis OUIPUT RDT acquisition (initial procurement and investment); and operating and support (O and consequent
3、ly, the engine manufacturer needs airframe data and vice versa. All the ingredients of Section 5.3.1 apply; but in addition, airframe costs are included. LCC analyses focused on Engine Studies are based on a Such studies may be conducted at any depth. System Studies: This type of LCC analysis applie
4、s to variable airframe and fixed engine situations Since the engine is fixed, there is no effect on engine cycle or engine size. Because airframe variations can impact engine usage, severity effects can be important considerations. The ingredients of paragraph 5.3.1 again apply; in addition, however
5、, the engine and airframe costs (often from probably different phases) are added together. Ground Rule Studies: In this situation, both the airfrariie and engine are fixed, but the scenario is variable. Typically, the impact of changes in the maintenance concept, mission details, delivery schedule,
6、economics, etc. are evaluated. variability impact should be consistent with the LCC phase. paragraph 5.3.3, engine and airframe costs are added as appropriate. Choice of such specific variables and their allowed As in 5.3.2 5.3.3 5.3.4 5.4 Projecting/Tracking: LCC tracking projections are used for c
7、ost control by design engineers, program managers, financial analysts and many others. Design engineers use LCC as a technical parameter for improving the engine system, That is, LCC is established as a technical parameter in the same sense and for the same purpose as performance parameters. Program
8、 managers use LCC tracking projections for program cost control. Similarly, financial analysts use LCC tracking projections for contract cost control Five elements of LCC tracking projections are (Figure 8): - initial base1 ine - previous projections - current status - future project ions - goal or
9、target The initial baseline LCC is the Initial Projection, sometimes called a calibration, of the total cost of an engine program from start to finish. The current status LCC is the Current Projection or most recent calibration of the total cost of an engine program from start to finish, The goal or
10、 target LCC is the projected cost of the engine program that has been establ.ished as an achievement objective for engine program participants. 5.4 (Continued): As the engine program proceeds, improvement changes usually are incorporated into he engine design and its program elements to reduce cost.
11、 The results are additional LCC projections generally (but not always) lower than the initial projection. LCC tracking projections that have been estimated for time periods prior to the current status LCC are Previous Projections. Similarly, LCC tracking. projections that are being estimated for tim
12、e periods beyond the current status LCC are Future Projections, as shown by Figure 8. LCC tracking projections are either or both of the following cost and cost re1 a ted da ta approat hes : - absolute - relative ADsolute data has not had a quantity multiplied, divided, subtracted, or added to it. A
13、bsolute data presents numerical values independent of a fiase1 i ne. Relative data has had a quantity multiplied, divided, subtracted, or added to it. or values (e.g., net change from an established baseline). Relative data presents numerical values dependent upon another value For clarity and impro
14、ved tracking projections, Life Cycle Costs can be separated as illustrated in Figure 9 (for a scenario different from that. depicted in Figure 8). Using this approach to LCC tracking projections, both cost and cost-related actual and updated projections can be better presented and controlled. Some v
15、ariants to the above recommended guidelines for LCC tracking projections are practiced by industry and government. . Specifically, the claimed baseline LCC might not be the Initial Projection. For example, sometimes the claimed baseline is the Current Status Projection. times the claimed baseline is
16、 the Goal or Target LCC. For this and other areas of LCC data presentation, both users and suppliers of LCC data should coordinate and mutually agree upon consistent LCC data presentation gui del ines. Breakouts of Life Cycle Cost tracking projections to several higher and lower indenture levels can
17、 be helpful to both LCC data presentation users and suppliers. When tracking projections of engine LCC, the engines ongoing credit and debit impacts on total system LCC (e.g., aircraft/fleet) should be reported. This should be coordinated and mutually agreed upon in advance by LCC data presentation
18、users and suppl iers. At other _- - . SAE AIR*L937 6 357340 0007338 4 - 12 - 5.4 (Continued): Improvement experience curves, al so cal led 1 earning curves, are frequently applied for tracking projections of cost and cost related LCC parameters. Many different learning curves of the fom y=AX-B are i
19、n use by industry and government. Plotted data can be a straight line on log-log. paper depending on whether the data are cumulative average or per unit data (Figure 10). Users and suppliers of LCC data should clearly indicate which data tracking projections arebeing presented, e.g., cumulative aver
20、age or per unit. Historical data actuals should be used as a basis to substantiate and/or verify LCC tracking projections. 5.5 Caution; Program managers, financial analysts, design engineers and other technical specialists should be aware of erroneous conclusions resulting from inappropriate input a
21、nd/or inappropriate comparisons with historical results, in spite of adequate LCC effort and valid LCC output. For example, a new engine program managed “business not as usual“ with novel engine design features might not follow historical trends. LCC analyses intended for engineering design activity
22、 might be inappropriate (without additional coordination and costing) for financial budget activity (see Figures 11 and 12). 5.5.1 Engine Fleet Size LCC Impact: dominant is the engine development cost. engine fleet size the more dominant is the engine acquisition, maintenance and fuel cost. With onl
23、y engine fleet size as a variable, a typical trend of impact on LCC percentage allocations is shown for a 50-50,000 unit range of engine fleet size (Figure 11). 5.5.2 Engine Program Life LCC Impact: more dominant is the engine development and acquisition cost. Conversely, the longer the engine progr
24、am life the more dominant is the engine maintenance and fuel cost. With only engine program life as a variable, a typical trend of impact on LCC percentage allocations is shown for a 1-45 year range of engine program life (Figure 12). 5.6 Coordination and Responsibility Requirements: As was indicate
25、d in Figure 1, LCC involves several different participants. Consequently, a well-coordinated LCC effort is important. Furthermore, many of the LCC functions addressed in this AIR can be accomplished by more than one of these participants. thorough del ineation of these responsibilities should be mad
26、e and understood by the LCC participants. For example, the amount of input/output detail can vary with program phase and funding. The smaller the engine fleet size the more Conversely, the larger the The shorter the engine program life the To reduce duplication and improve productivity, a - 13 - 6.
27、INPUT: There are no rigid guidelines which can be applied to classify input information used to calculate aircraft engine Life Cycle Cost. elsewhere, parameters regarded as an input to one analysis, i.e., shop visit rate goal, can in different circumstances be correctly identified as an output. Some
28、times the same parameter is utilized as both an input and an output. This apparent anomaly is illustrated in Figure 13. “scoping“ study, Life Cycle Cost and possibly even RDT and such parameters will change with both time and specific program details, A separate advance request (possibly in the Kequ
29、est for Proposal, if extensive) should be made of the Engine Producer(s1 to provide any such ( non-cos t or tented ) i nfortnat i on. The need to provide additional output 8. COLLABORATION: communications in col laborative ventures. The fol lowing describes the principal areas which generally need t
30、o be addressed to ensure successful pursuit of LCC objectives. aanguage. To assist non-English speaking nations, the Simplified English System should be used wherever possible. This system was developed by AECMA and agreed to by AIA. Guide1 ines presented in AIR 1939 establish a framework for 8.1 La
31、n ua e: In a multi-lingual collaboration, English is suggested for a (See paragraph 10.4, Reference 27.) 8.2 Accounting: Each LCC participant may have different accounting practices, e.g., overhead structures and methods of overhead recovery. effective cost comparisons can be made, close attention s
32、hould be directed to detailed agreement of definitions of cost structure elements. practices should be coordinated for effective cost control. To ensure that Accounting 8.3 Currency and Inflation: In a mu1 ti -currency col laboration, cost should be translated to a comnon currency or LCC Index. vari
33、ations in exchange rate and differential inflation rates might distort the contributions of cost elements with time. of tracking and controlling project costs. Formulae can be embodied in the cost calculation process to minimize these effects. There is a danger that This increases the difficulty 8.4
34、 Tracking and Monitori ng: Important agreements i ncl ude: o Datum designs against which improvements can be measured o Targets for LCC elements o Procedures for adjustment to above o Mechani sms for moni tori ng progress o Working practices for LCC 8.5 Data: Common questionnai res should be adopted
35、 for obtaining information from customer, suppliers, etc., at different phases of the project. formats and routes for data feedback from operators should be established to ensure a coordinated approach to i n-service support and management. Common 9. TERMINOLOGY AND GLOSSARY: 9.1 Acronyms and Abbrev
36、iations: AECMA Association Europeenne Des Constructeurs De Materiel Aerospatial AIA Aero space Indus tri es Assoc i a ti on AIR Aero space I nf ormat i on Report ARP Aerospace Recommended Practice AS Ae ro s pace Standard CERT FAA Certification Test CIP Component Improvement Program CONUS Continenta
37、l United States DOD Department Of Defense DT Development Test D TC Design To Ost DTUPC DTLCC FMECA F SD Fu1 1 Scal e Development FSP Fu1 1 Scale Production Design To Unit Production Cost Design to Life Cycle Cost Fail Ure Mode, Effects and Cri tical i ty Analysis - 20 - 9.1 (Continued) : GFE I IS J
38、RMB LCC LI? IP LSAR MCT M TBF WTTK NAS O hence, a value established on a Cost Growth: estimated or actual amount over a base figure previously established, The base should be reatable to a program, project, or contract and be clearly identified including source, approval authority, specific items in
39、cluded, specific assumptions made, date, and amount. Cost growth is a term related to the net change of an - 21 - 9.2 ( Conti nue d ) : Cost Model: An ordered arrangement of data and equations that permits translating physical resources into costs. A mathematical device used to develop estimates and
40、 output formats for presentations. The model consists of an input format to specify the problem; information, including both system description data and estimating relationships; and an output format. Cost of Ownership: operating and support cost category exclusively. paragraph 10.2, Government Docu
41、ments. 1 Ownership costs encompass the cost elements within the (See Reference 3 of Cost Parameters: bands. Cost threshold is the upper boundary value of cost which should not be exceeded. Cost brackets or band is the acceptable range of cost for the perf o ma nce band. Cost parameters are cost thre
42、sholds and cost brackets or Cost Trackin : between planned or projected versus actual costs. Generally, a process which collects and evaluates data in etennini ng the reasons for variances between successi ve cost estimates or DELPHI Technique: estimates. They are asked to estimate the cost for a sy
43、stem displaying certain specified characteristics. Their responses are summed and a mean, standard deviation or range established. This data is fed back to the experts in another letter and they are allowed to change their estimates, if they desi re. After several interactions, an order of magnitude
44、 estimate (the mean ) resul ts. A pol 1 i ng technique often used to make expert opinion The experts in a given technical area are polled by letter. Design to Cost Design to Unit Production Cost (DTUPC): achieve system designs that meet stated cost requirements. Design to cost Cl and design to Life
45、Lycle Cost (DiLCC) a re management techniques to Disposal Cost: Dlsposal cost is the sum of all contract and government in-house costs required to remove the system or equipment from the inventory, and which may be offset by some residual value (e.g., salvage or resal e ). Economic Analysis: A syste
46、matic approach to the problem of choosing how to employ scarce resources and an investigation of the full implications of achieving a given objective in the most efficient and effective manner. determination of efficiency and effectiveness is implicit in the assessment of the cost effectiveness of a
47、l ternative approaches. The Equipment: procured for installation in a system or to support a system. Refers col lecti vely to an item, component, or sub-system Expert Opinion Estimating: experts in the field. “state-of-the-art“ technology or systems. experts. (See DELPHI Technique. ) Estimating cost
48、s based on the opinion of the Especially useful when estimating costs for Involves a DELPHI polling of the _ _ _s_ -_- SAE AIR*1939 b II 83573VO 0007148 7 9.2 (Cont Force Goal : - - 22 - nued) : Structure: Fleet size structure. (See paragraph 6.4.) Normally a fim number (sometimes interchangeable wi
49、th “target“) Industrial Engineering Estimate: Used primarily to estimate recurring production or investment costs and involves the build-up of costs by detailed analysis of work processes and material. examination of separate segments of work at a low level of detail and a synthesis of the many detailed estimates into a total (bottom-up estimate). Investment Cost: of contractor and government in-house costs, both non-recurring and recurring, required to transform the results of R&D into a fully deployed operational system or equi
