A formal methods approach to the analysis of mode confusion

TLDR

Pilot error, responsible for up to 70% of fatal accidents, is mainly caused by loss of situation awareness, with mode confusion increasingly contributing. The NASA Aviation Safety Program seeks to reduce civil aviation fatal accidents by 80% in ten years and 90% in twenty, and this paper explores using formal models to eliminate mode confusion in flight deck designs and enhance safety confidence. The program is driven by recent accident data, and the study applies formal methods to a realistic business jet Flight Guidance System to address mode confusion. Interim results from a NASA Langley–Rockwell Collins project applying formal methods to a realistic business jet Flight Guidance System show progress toward eliminating mode confusion.

Abstract

The goal of the new NASA Aviation Safety Program (AvSP) is to reduce the civil aviation fatal accident rate by 80% in ten years and 90% in twenty years. This program is being driven by the accident data with a focus on the most recent history. Pilot error is the most commonly cited cause for fatal accidents (up to 70%) and obviously must be given major consideration in this program. While the greatest source of pilot error is the loss of situation awareness, mode confusion is increasingly becoming a major contributor as well. This paper will explore how formal models and analyses can be used to help eliminate mode confusion from flight deck designs and at the same time increase our confidence in the safety of the implementation. The paper is based upon interim results from a new project involving NASA Langley and Rockwell Collins in applying formal methods to a realistic business jet Flight Guidance System (FGS).