An Exploration of Function Analysis and Function Allocation in the Commercial Flight Domain
Abstract
Two approaches to function analysis and to function allocation were investigated. One function analysis approach ("Bottom-Up") extracted functions from a very detailed task time line (TTL) database. These were the functions that might have been implemented to produce the task performance documented in the TTL. A second approach ("Top-Down") created a functional architecture of the objective "Accomplish Commercial Transport Missions" using the function modeling method "Structured Analysis and Design Technique (SADT). Comparable functions were found for both methods in the "Lift-Off' segment, at the lowest level of decomposition. In the "Bottom-Up" approach, although the analysts attempted to eliminate references to any specific design implementation, its content might be influenced by the existing allocations. The "Top-Down" model made no assumptions about automation. The "Bottom-Up" approach was valuable in relating functions to the time interval of the mission during which they occurred. It also provided the capability for relating the "Top-Down" model (which does not address time or sequence) to the mission time line. Both methods are valuable. A detailed treatment of each model is given in the Appendices. The first approach to function allocation, Method A, is a comprehensive, iterative process that is integrated with the system engineering effort. It emphasizes the iteration of the three steps of allocation, design and evaluation. This method explicitly incorporates a "human-centered" approach to allocation, viewing the human operator as a multidimensional resource whose cognitive and performance characteristics must directly influence the allocation process. This method also encourages the development of adaptive allocation schemes capable of making on-line decisions responsive to situation-specific changes on the flight deck. The second approach, Method B, is a relatively brief, simplified system designed to provide an effective first cut allocation.
Document Details
- Document Type
- Technical Report
- Publication Date
- Nov 01, 1991
- Accession Number
- ADA574202
Entities
People
- James C. Mcguire
- Jeffery B. Erickson
- John A. Zich
- John P. Dwyer
- Richard T. Goins
- William B. Rouse
- William J. Cody
Organizations
- Douglas