Fuel consumption modeling of a transport category aircraft: A Flight Operations Quality Assurance (FOQA) analysis

Fuel is a very large operating cost category for major air carriers—second only to labor costs. Many air carriers have implemented extensive programs to monitor fuel usage. One of several emerging quality assurance programs in the aviation industry, Flight Operations Quality Assurance (FOQA) involves the routine collection and analysis of flight performance data recorded on the airplane for the purpose of improving safety and operational procedures. FOQA systems are not constrained by the same data limitations as are traditional aircraft performance monitoring programs and, thus, FOQA may serve as a robust new aircraft performance monitoring tool.; The purpose of the study was to develop a parsimonious model(s) for fuel consumption on a Boeing 757 airplane using statistical tools to analyze FOQA-derived data, with the objective of being able to identify outliers (specific flights) with respect to fuel consumption. The identification of outliers will enable the air carrier to investigate the cause of excessive fuel consumption and remedy the problem.; A major air carrier provided a database of nearly 3,500 flights for the study. The determination of potential predictor variables was made based on the airplane manufacturer's technical documentation. The study considered one data point per flight, during the cruise phase only. This data point was selected based on an algorithm designed to mimic the aircraft data system manufacturer's program for determining stable engine cruise conditions. Regression analysis was used to create a model for each engine.; Fuel flow was predicted by calibrated airspeed (CAS), gross weight (GWeight), and n2 (ENG[1 or 2]n2). The models containing these three variables explained approximately 85% of the variation in fuel flow. A reporting routine using these models and FOQA data should be incorporated into the ongoing quality assurance program of the air carrier to detect excessive fuel consumption. It was also determined that the actual fuel flow was significantly greater than that projected by the manufacturer, which supported findings from other studies.