16.885J/ESD.35J - Nov 18, 2003 16.885J/ESD.35J Aircraft Systems Engineering Lean Systems Engineering II November 18, 2003 Prof. Earll Murman16.885J/ESD.35J - Nov 18, 2003 Systems Engineering and Lean Thinking • Systems Engineering grew out of the space industry in response to the need to deliver technically complex systems that worked flawlessly upon first use – SE has emphasized technical performance and risk management of complex systems. • Lean Thinking grew out of the Japanese automobile industry in response to the need to deliver quality products with minimum use of resources. – Lean has emphasized waste minimization and flexibility in the production of high quality affordable products with short development and production lead times. • Both processes evolved over time with the common goal of delivering product or system lifecycle value to the customer.16.885J/ESD.35J - Nov 18, 2003 Lean Systems Engineering Value Phases Value Value Value DeliveryIdentification Proposition Identify the Develop a robust Deliver on the promise stakeholders and value proposition with good technical their value to meet the and program expectations expectations performance • Lean Systems Engineering (LeanSE) applies the fundamentalsof lean thinking to systems engineering with the objective ofdelivering best lifecycle value for complex systems and products. • An example of lean thinking applied to systems engineering is the use of IPPD and IPTs - see Lean Systems Engineering I lecture. • Understanding and delivering value is the key concept to LeanSE • A broad definition of value is how various stakeholders find particular worth, utility, benefit, or reward in exchange for their respective contributions to the enterprise.16.885J/ESD.35J - Nov 18, 2003 Today’s Topics • Recap of system engineering fundamentals • Revisit fundamentals of lean thinking – Value principles, the guide to applying lean thinking – Lean Enterprise Model (LEM), a reference foridentifying evidence of lean thinking applied to anenterprise • Comparison of F/A-18E/F practices to the LEM – An example of looking for evidence of LeanSE • Examples of LeanSE extracted from various Lean Aerospace Initiative research projects16.885J/ESD.35J - Nov 18, 2003 Simplified Systems Engineering Process Steps Functional Analysis Needs: •End user •Customer •Enterprise •Regulatory Requirements Verification Synthesis Production, Delivery & Operation Validation Systems engineering process is applied recursively at multiple levels: system, subsystem, component. Source: Adapted f rom Jackson, S. Systems Engineering for Commercial Aircraft16.885J/ESD.35J - Nov 18, 2003 Other Systems Engineering Elements • Allocation of functions and “budgets” to subsystems • Interface management and control •IPPD • Trade studies • Decision gates or milestones – SRR, SDR, PDR, CDR,… • Risk management • Lifecycle perspective16.885J/ESD.35J - Nov 18, 2003 Fundamentals For Developing a Lean Process Value Phases Value Value Value DeliveryIdentification Proposition • Specify value: Value is defined by customer in terms ofspecific products & services • Identify the value stream: Map out all end-to-end linkedactions, processes and functions necessary fortransforming inputs to outputs to identify and eliminatewaste (Value Stream Map or VSM) • Make value flow continuously: Having eliminated waste,make remaining value-creating steps “flow” • Let customers pull value: Customer’s “pull” cascades all the way back to the lowest level supplier, enabling just-in-time production • Pursue perfection: Pursue continuous process ofimprovement striving for perfection Source: James Womack and Daniel T. Jones, Lean Thinking (New York: Simon & Schuster, 1996).16.885J/ESD.35J - Nov 18, 2003 Value - Slack’s definition A more specific definition of value useful for system development is given by Slack: “Value is a measure of worth of a specific product or service by a customer, and is a function of (1) the product’s usefulness in satisfying a customer need, (2) the relative importance of the need being satisfied, (3) the availability of the product relative to when it is needed and (4) the cost of ownership to the customer.” (1) and (2) relate to Performance ( or quality) (3) relates to Schedule (4) relates to Cost/Price Achieving Performance, Schedule, and Cost objectives with acceptable risk is the generic challenge in developing products and systems. Source: Slack, R, “The application of Lean Principles to the Military Aerospace Product Development Process” MIT SM Thesis, Dec 199816.885J/ESD.35J - Nov 18, 2003 Examples of Value Metrics Performance Cost Schedule • Vehicle performance • Development • Acquisition (range-payload,speed, maneuver costs response time, or parameters) lead time • Production costs, – Recognition time • Ilities (Quality, nonrecurring andreliability, – Initiation time – Productmaintainability, recurring developmentupgradability) • Operation costs cycle time• System compatibility • Upgrade or • Order to ship time(ATC, airportinfrastructure, conversion costs – Lead time mission • Disposal costs – Production cyclemanagement) time • Environmental • In-service turn (Noise, emissions, total environmental around time impact) Value provides a multidimensional framework16.885J/ESD.35J - Nov 18, 2003 Value: A Symbolic Representation fp( performance )Value = fc(cos t)• f (time )t • Similar to definition developed by valueengineers, value = function/cost • Value defined by the customer for each systemor product • Comprised of specific performance, cost,schedule metrics with weightings representingcustomer utility functions and normalizations forconsistency Source: Murman, E.M., Walton, M., and Rebentisch, E. “Challenges in the Better, Faster, Cheaper Era of Aeronautical Design, Engineering and Manufacturing”, The Aeronautical Journal, Oct 2000, pp 481-48916.885J/ESD.35J - Nov 18, 2003 Waste Happens In Product Development • Effort is wasted – 40% of PD effort “pure waste”, 29% “necessary waste” (LAI PD workshop opinion survey) – 30% of PD charged time “setup and waiting” (aero and auto industry survey) • Time is wasted – 62% of tasks idle at any given time (LAI detailed member company study) – 50-90% task idle time found in Kaizen- type events pure waste value