How a cockpit calculates its speeds and why errors while doing this are so hard to detect

Recent incidents have shown that the production of take-off speeds is an activity vulnerable to miscalculations with a potential for disastrous outcomes. The aim of this paper is to analyze the calculation of the take-off speeds in a modern airline cockpit as a distributed cognitive activity in order to identify possible vulnerabilities in this process. We took the cockpit as the joint cognitive system under analysis and conducted an ethnographic study based on documental analysis, flight observations, interviews, and the analysis of 22 events involving failures related to the calculation of take-off speeds. The main argument is that the cognitive systems engineering perspective, with less focus on the human contribution than it is common in investigations, levels people and artifacts in the system as equal contributors to its eventual performance. Our analysis identified four assertions regarding vulnerabilities in the process of take-off speeds calculation: (1) representations at the level of the cockpit are always partial and incomplete; (2) some interactions require interpretation rather than institution; (3) interactions of agents do not follow a canonical process of coordination; (4) the control of the prevention of failures is accurate but inadequate. These vulnerabilities are a matter of interactions among cognitive systems in the cockpit, rather than vulnerabilities of individual agents, such as humans or artifacts.