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Altitude deviations: Breakdowns of an error-tolerant systemPilot reports of aviation incidents to the Aviation Safety Reporting System (ASRS) provide a window on the problems occurring in today's airline cockpits. The narratives of 10 pilot reports of errors made in the automation-assisted altitude-change task are used to illustrate some of the issues of pilots interacting with automatic systems. These narratives are then used to construct a description of the cockpit as an information processing system. The analysis concentrates on the error-tolerant properties of the system and on how breakdowns can occasionally occur. An error-tolerant system can detect and correct its internal processing errors. The cockpit system consists of two or three pilots supported by autoflight, flight-management, and alerting systems. These humans and machines have distributed access to clearance information and perform redundant processing of information. Errors can be detected as deviations from either expected behavior or as deviations from expected information. Breakdowns in this system can occur when the checking and cross-checking tasks that give the system its error-tolerant properties are not performed because of distractions or other task demands. Recommendations based on the analysis for improving the error tolerance of the cockpit system are given.
Document ID
Document Type
Technical Memorandum (TM)
Palmer, Everett A.
(NASA Ames Research Center Moffett Field, CA, United States)
Hutchins, Edwin L.
(California Univ. San Diego., United States)
Ritter, Richard D.
(NASA Ames Research Center Moffett Field, CA, United States)
Vancleemput, Inge
(Wellesley Coll. MA., United States)
Date Acquired
September 6, 2013
Publication Date
October 1, 1993
Subject Category
Air Transportation And Safety
Report/Patent Number
NAS 1.15:108788
Accession Number
Funding Number(s)
PROJECT: RTOP 505-64-13
Distribution Limits
Work of the US Gov. Public Use Permitted.
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