Aircraft Performance in Slippery Runway Conditions: A Simulation Study of the Accuracy and Limitations of Real-Time Runway Friction Estimatoin Based on Airplane Onboard Data
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Publication Date: |
04-2015 |
| Authors: |
Andrew Cheng, PhD. van Es, Gerard W.H. van der Geest, Peter J. Stimson, Don |
van Es, G.W.H., van der Geest, P.J., Cheng, A.Y. & Stimson, D. (2015) Aircraft Performance in Slippery Runway Conditions: A Simulation Study of the Accuracy and Limitations of Real-Time Runway Friction Estimation Based on Airplane Onboard Data, DOT/FAA/TC-14/32, FAA William J. Hughes Technical Center, Aviation Research Division, Atlantic City International Airport NJ
Abstract
Runway overrun accidents occurring during landings in slippery conditions continue to occur frequently worldwide. After a number of specific landing overrun accidents in the U.S., the National Transportation Safety Board (NTSB) issued a safety recommendation to investigate the technical and operational feasibility of outfitting transport category airplanes with equipment and procedures required to routinely calculate, record, and convey the airplane’s braking ability. In this context, this study developed an algorithm for real-time onboard runway friction estimation. The algorithm was demonstrated in a high-fidelity simulation test that applied data and knowledge of detailed aerodynamic and engine models to represent a specific regional jet. The primary objective was to evaluate the impact of measurement and modeling errors to the runway friction estimation obtained from the algorithm. The simulation showed that onboard runway friction estimation can provide an accuracy of approximately ±5%; measuring errors based on realistic sensor noise and bias. However, to achieve such performance, a fairly precise estimate of instantaneous thrust, weight, and drag is required. It was noted that 1% of inaccuracy in these quantities translates directly into at least a 1% estimate error. A representative model of the ground effect is also critical to the estimation accuracy. Nevertheless, errors in the calculation of aerodynamic lift and pitching moment seemed to be negligible. The results of this study can be further used to define an operational concept in line with the recommendation of the NTSB.
