Drucella Andersen
Headquarters, Washington, D.C.                                    
September 29, 1993
(Phone:  202/358-4727)

H. Keith Henry
Langley Research Center, Hampton, Va.
(Phone:  804/864-6120)

Hank Price
Federal Aviation Administration, Washington, D.C.
(Phone:  202/267-3447)

RELEASE: 93-171

NASA, FAA CONSIDER REVISED WINDSHEAR PILOTING PROCEDURES 

     NASA and the Federal Aviation Administration (FAA) are 
considering whether pilots should have formal training to interact 
with new aircraft instruments able to give advance warning of 
windshear -- sudden changes in wind speed and direction that can 
endanger aircraft during takeoff and landing. 

     Training consideration comes after 7 years of windshear 
studies by NASA and the FAA.  The joint effort included research 
on windshear hazards, flight tests of three new advance-warning 
sensors and studies of pilot response to displays generated by 
data from the devices. The recommendations were reported at a 
NASA/FAA windshear meeting in Hampton, Va. 

     "Forward-looking windshear sensors could be available to 
airlines by the end of this year," said Rosa Oseguera of NASA's 
Langley Research Center, Hampton, Va.  "We believe the most 
effective use of the sensors requires an industry standard on 
displays, a consensus on proper crew procedures for reacting to 
the information and training to put those procedures into effect."

     Windshear was a factor in air accidents that caused at least 
500 deaths from 1964 to 1985.  In 1987, the FAA created training 
aids to help pilots identify the phenomenon and escape if they 
unexpectedly enter a windshear.


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     Oseguera and NASA engineer David Hinton outlined NASA's 
suggested displays and pilot actions for use by the FAA, aircraft 
manufacturers and air carriers.  Because the new sensors can give 
up to 40 seconds warning of a
windshear encounter, the procedures consider how far away the 
windshear is and where it is in relation to the plane's flight 
path.

     If the displays show a windshear more than 3 miles away or to 
the side of the flight path during the approach to the runway, for 
example, pilots would normally fly around the threat.  If a 
windshear is on the flight path within 3 miles, pilots would 
either execute "missed approach" procedures or fly around it after 
clearance from air traffic controllers.  

     A warning of windshear less than 1.5 miles ahead would 
dictate a straight-ahead escape, since there might not be enough 
time to contact controllers, get clearance and turn away from the 
hazard.  The new sensors make this procedure possible because 
transport aircraft normally have power to fly through windshear if 
the pilots know about the hazard in advance and take appropriate 
actions. 

     Similar rules would apply to windshear spotted during 
takeoff, but the distance guidelines are somewhat different.

    "Training based on use of the new sensors would let pilots 
evade windshears when possible, but also would make sure they can 
fly through them safely if contact can't be avoided," said Herbert 
Schlickenmaier, Program Manager at NASA Headquarters, Washington, 
D.C.  "These procedures would expand on, not replace, current 
FAA-mandated techniques for avoiding windshear."

     NASA and the FAA began the joint windshear research program 
in 1986 to reduce the hazard to transport-type aircraft during 
takeoff and approach.  A NASA Boeing 737 successfully 
flight-tested three types of forward-looking sensors in 1991 and 
1992: microwave radar, Doppler LIDAR (laser radar) and infrared.

  "There are a number of tools available to reduce the hazard 
from the windshear threat.  The ability to detect, locate and 
quantify this threat and relate it to aircraft performance 
capability, which these latest devices provide, is a tribute to 
all the participants in this program," said George C. "Cliff" Hay, 
FAA airborne windshear program manager.

     These instruments are "predictive" sensors, in contrast to 
"reactive" sensors that alert pilots only after a plane enters a 
windshear.  FAA regulations say that reactive systems must be 
installed by most U.S. airlines by the end of 1993.  Continental, 
Northwest and American Airlines asked for and got exemptions that 
would let them put predictive sensors in their aircraft by 1995.

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