"Oops, It didn't arm." - A Case Study of Two Automation Assisted Altitude Deviations
Altitude deviations are the most common pilot error reported to the Aviation Safety Reporting System. Last year, altitude deviations were reported to the ASRS at the rate of about one per hour. The reporting pilot's narrative is usually our only source of information about what happened in these incidents. In a recent line-oriented, simulator study, twenty-two airline crews flew a realistic, two-hour mission in a DC-9 and an MD-88 aircraft. This paper will describe and analyze two of the five altitude deviations that were observed during this study. The paper focuses on the flight crews' use (or misuse) of the autopilot and autothrottle during these incidents.