Ian Sheppard/LONDON
NASA is calibrating a new runway-friction indexing method designed to prevent aircraft accidents on icy runways, after it was realised that poor surface-friction information had contributed to incidents where aircraft have slid off the runway or been dangerously slow to reach lift-off speed.
The NASA-led tests in Ontario, Canada, are comparing friction measurements from ground vehicles with aircraft performance in different winter conditions, and are intended to verify an international runway-friction index, then relate it to aircraft types and sizes. "The index will be a single, accurate and easy-to-use tool to help pilots and airport operators assess conditions quickly," says lead NASA engineer Thomas Yager.
The index - probably in the form of a simple chart, "will help pilots with 'go/no-go' decisions based on readings taken by a ground friction-measurement vehicle on the same runway", says NASA.
The indexing method has "harmonised" traction measurements from 13 different ground vehicles on ice, snow and slush-covered runways at Ontario's North Bay. A Bombardier de Havilland Dash 8 and Dassault Falcon 20 are being used to take complementary traction data from actual take-offs and landings on the same runways at each surface condition.
The research is a joint effort led by NASA and TransportCanada and is supported by the US Federal Aviation Administration, Canada's National Research Council and airframe makers, with participation from European organisations.
The research team is half-way through the five-year Joint Winter Runway Friction Measurement programme. A better understanding of runway friction will help to improve tyre designs, develop better chemical treatments for snow and ice and new runway surfaces.
Source: Flight International
