Don Nolan
Headquarters, Washington, DC           March 15, 1996
(Phone:  202/358-1983)
Keith Henry
Langley Research Center, Hampton, VA
(Phone:  804/864-6120)
Angelo Boccanfuso
Transport Canada
(Phone:  514/283-0862)
Les Dorr
FAA Headquarters, Washington, DC
(Phone:  202/267-3461)
RELEASE:  96-52
WINTER RUNWAY SAFETY SUBJECT OF NEW STUDY
     The safety of aircraft takeoffs and landings will be 
enhanced with the knowledge and operational procedures 
expected from a new study of winter runway friction now 
underway.
     The five-year government/industry study, called the 
Joint Winter Runway Friction Measurement Program, is being 
led by NASA and Transport Canada with support from the 
Federal Aviation Administration (FAA).  Also participating 
are organizations and equipment manufacturers from Europe 
and several Scandinavian countries.
     The study will include braking tests with instrumented 
aircraft and ground vehicles in the U.S. and Canada.  
Results are expected to enhance safety for all ground 
operations and help relieve airport congestion during bad 
weather.  Results also will help industry develop improved 
tire designs, better chemical treatments for snow and ice 
control, more reliable ground vehicle friction measuring 
systems and runway surfaces that minimize bad weather 
effects.
     Flight crew recognition of less-than-acceptable 
reported runway friction conditions prior to the "go/no go" 
or the "land/go around" decision point is one of the near-
term program goals.
     NASA's B-737 research aircraft and Canada's National 
Research Council Falcon-20 aircraft completed a week-long 
series of landing tests earlier this month on ice- snow- and 
slush-covered runways at the Jack Garland Airport in North 
Bay, Ontario, Canada, about 200 miles north of Toronto.
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     Surface conditions were artificially varied to expand 
the range of data collected.   Many different runway 
friction-measuring ground vehicles -- vans, trailers and 
modified cars -- took readings with continuous and fixed 
slip devices under similar runway conditions for comparison 
with each other and with the braking performance of the two 
instrumented aircraft.  
     Winter runway evaluations also are planned at the 
Brunswick Naval Air Station, Maine.  Water contamination 
studies are planned at NASA's Wallops Flight Facility, 
Wallops Island, VA, and the FAA Technical Center in New 
Jersey.   
     "Data from the program will be used to quantify exactly 
how much improvement has been made in measuring runway 
friction since we performed similar tests with the FAA a 
decade ago.  We hope to learn enough over the course of the 
study to confidently recommend international guidelines for 
aircraft and airport ground operations in winter weather, 
said Thomas Yager, lead NASA engineer on the project.
     Broad-based changes in the industry since the 1980's 
strongly suggested a follow-up to the first NASA-FAA study, 
conducted between 1983 and 1988.   Improved measurement 
equipment, computer software and test procedures need to be 
evaluated.  Data is also needed on new anti- and de-icing 
chemicals, water/slush drag effects on new aircraft types 
and tire construction effects on hydroplaning. 
     The study also was suggested by strong international 
support for developing a standardized set of guidelines for 
runway friction measurement and reporting.  In spite of 
advances in technology and operational procedures, safe 
winter operations remain a challenge for airport operators, 
air traffic controllers, airlines and pilots who must 
coordinate their efforts under rapidly-changing weather 
conditions.
     Complicating the winter weather picture is that 
criteria for safe operations on a given runway snow 
condition differ from airport to airport, due to differences 
in grooving and pavements.  Obtaining data relating various 
winter runway friction numbers to aircraft stopping distance 
requirements would be a significant step toward the 
development and adoption of standardized guidelines or 
tables to be used by pilots.
     NASA, the FAA and Transport Canada have cooperated in 
several ground vehicle and instrumented aircraft studies 
aimed at improving aircraft ground performance in bad 
weather.  NASA and the FAA worked together as early as the 
1950's to establish early slush depth criteria for runway 
operations.  A spin-off from later NASA aircraft 
hydroplaning studies resulted in the widespread practice of 
grooving automotive highways to improve tire traction during 
rainstorms.  
     In a modern spin-off application, much of the equipment 
being used to monitor runways is or will be used to measure 
highway pavement friction performance.  In areas with high 
accident rates, pavement textures can be modified based on 
readings from ground friction measurement vehicles to 
improve the safety of automotive travel.
                    -end-