[1]. James R. Hansen, Engineer in Charge: a History of the Langley Aeronautical Laboratory, 1917–1958, NASA SP-4305 (Washington, DC: GPO, 1987), p. 76.
[2]. Theodore von Kármán, Aerodynamics (New York: Dover Publications, 2004 ed.), pp. 86–91.
[3]. Terry Zweifel, “Optimal Guidance during a Windshear Encounter,” Scientific Honeyweller (Jan. 1989), p. 110.
[4]. Integrated Publishing, “Meteorology: Low-Level Wind Shear,” http://www.tpub.com/weather3/6-15.htm,accessed July 25, 2009.
[5]. National Center for Atmospheric Research, “T-REX: Catching the Sierra’s Waves and Rotors,” http://www.ucar.edu/communications/quarterly/spring06/trex.jsp, accessed July 21, 2009.
[6]. T. Theodore Fujita, “The Downburst, Microburst, and Macroburst,” Satellite and Mesometeorology Research Project [SMRP] Research Paper 210, Dept. of Geophysical Sciences, University of Chicago, NTIS Report PB-148880 (1985).
[7]. For microbursts and NASA research on them, see the recommended readings at the end of this paper by Roland L. Bowles, Kelvin K. Droegemeier, Fred H. Proctor, Paul A. Robinson, Russell Targ, and Dan D. Vicroy.
[8]. NASA has undertaken extensive research on wind shear, as evidenced by numerous reports listed in the recommended readings section following this study. For introduction to the subject, see NASA Langley Research Center, “Windshear,” http://oea.larc.nasa.gov/PAIS/Windshear.html, accessed July 30, 2009; Integrated Publishing, “Meterology: Low-Level Wind Shear,” http://www.tpub.com/weather3/6-15.htm, accessed July 25, 2009; Amos A. Spady, Jr., Roland L. Bowles, and Herbert Schlickenmaier, eds., Airborne Wind Shear Detection and Warning Systems, Second Combined Manufacturers and Technological Conference, two parts, NASA CP-10050 (1990); U.S. National Academy of Sciences, Committee on Low-Altitude Wind Shear and Its Hazard to Aviation, Low Altitude Wind Shear and Its Hazard to Aviation (Washington, DC: National Academy Press, 1983); and Dan D. Vicroy, “Influence of Wind Shear on the Aerodynamic Characteristics of Airplanes,” NASA TP-2827 (1988).
[9]. Department of Atmospheric Sciences, University of Illinois-Champaign, “Jet Stream,” http://ww2010.atmos.uiuc.edu/%28Gh%29/guides/mtr/cyc/upa/jet.rxml, accessed July 25, 2009. Lightning aspects of the thunderstorm risk are addressed in an essay by Barrett Tillman and John Tillman in this volume.
[10]. Statistic from Emedio M. Bracalente, C.L. Britt, and W.R. Jones, “Airborne Doppler Radar Detection of Low Altitude Windshear,” AIAA Paper 88-4657 (1988); see also Joseph R. Chambers, Concept to Reality: Contributions of the NASA Langley Research Center to U.S. Civil Aircraft of the 1990s, NASA SP-2003-4529 (Washington, DC: GPO, 2003), p. 185; NASA Langley Research Center, “Windshear,” http://oea.larc.nasa.gov/PAIS/Windshear.html, accessed July 30, 2009.
[11]. U.S. Department of Energy, “Ask a Scientist,” http://www.newton.dep.anl.gov/aas.htm, accessed Aug. 5, 2009.
[12]. BBC News, “Jet Streams in the UK,” http://www.bbc.co.uk/weather/features/understanding/jetstreams_uk.shtml, accessed July 30, 2009; M.P. de Villiers and J. van Heerden, “Clear Air Turbulence Over South Africa,” Meteorological Applications, vol. 8 (2001), pp. 119–126; T.L. Clark, W.D. Hall, et al., “Origins of Aircraft-Damaging Clear-Air Turbulence During the 9 December 1992 Colorado Downslope Windstorm: Numerical Simulations and Comparison with Observations,” Journal of Atmospheric Sciences, vol. 57 (Apr. 2000), p. 20.
[13]. National Transportation Safety Board, “Aircraft Accident Investigation Press Release: United Airlines Flight 826,” http://www.ntsb.gov/Pressrel/1997/971230.htm, accessed July 30, 2009.
[14]. Aviation Safety Network, “ASN Aircraft accident Boeing 747 Tokyo,” http://aviation-safety.net/database/record.php?id=19971228-0, accessed July 4, 2009.
[15]. U.S. Department of Energy, “Ask a Scientist,” http://www.newton.dep.anl.gov/aas.htm, accessed Aug. 20, 2009.
[16]. M.D. Klaas, “Stratocruiser: Part Three,” Air Classics (June 2000), at http://findarticles.com/p/articles/mi_qa3901/is_200006/ai_n8911736/pg_2/, accessed July 8, 2009.
[17]. Ned Rozell, Alaska Science Forum, “Amazing flying machines allow time travel,” http://www.gi.alaska.edu/ScienceForum/ASF17/1727.html, accessed July 8, 2009.
[18]. U.S. Weather Service, “Wind Gust,” http://www.weather.gov/forecasts/wfo/definitions/defineWindGust.html, accessed Aug. 1, 2009.
[19]. Richard P. Hallion, Taking Flight: Inventing the Aerial Age from Antiquity Through the First World War (New York: Oxford University Press, 2003), p. 161.
[20]. J.C. Hunsaker and Edwin Bidwell Wilson, “Report on Behavior of Aeroplanes in Gusts,” NACA TR-1 (1917); see also Edwin Bidwell Wilson, “Theory of an Airplane Encountering Gusts,” pts. II and III, NACA TR-21 and TR-27 (1918).
[21]. For an example of NACA research, see C.P. Burgess, “Forces on Airships in Gusts,” NACA TR-204 (1925). These—and other—airship disasters are detailed in Douglas A. Robinson, Giants in the Sky: A History of the Rigid Airship (Seattle: University of Washington Press, 1973).
[22]. Ludwig Prandtl, “Some Remarks Concerning Soaring Flight,” NACA Technical Memorandum no. 47 (Oct. 1921), a translation of a German study; Howard Siepen, “On the Wings of the Wind,” The National Geographic Magazine, vol. 55, no. 6 (June 1929), p. 755. For an example of later research, see Max Kramer, “Increase in the Maximum Lift of an Airplane Wing due to a Sudden Increase in its Effective Angle of Attack Resulting from a Gust,” NACA TM-678 (1932), a translation of a German study.
[23]. Walter Georgii, “Ten Years’ Gliding and Soaring in Germany,” Journal of the Royal Aeronautical Society, vol. 34, No. 237 (Sept. 1930), p. 746.
[24]. Siepen, “On the Wings of the Wind,” p. 771.
[25]. Ibid., pp. 735–741; see also B.S. Shenstone and S. Scott Hall’s “Glider Development in Germany: A Technical Survey of Progress in Design in Germany Since 1922,” NACA TM No. 780 (Nov. 1935), pp. 6–8.
[26]. See also James R. Hansen, Engineer in Charge: A History of the Langley Aeronautical Laboratory, 1917–1958, NASA SP-4305 (Washington, DC: GPO, 1987), p. 181; and Hansen, The Bird is on the Wing: Aerodynamics and the Progress of the American Airplane (College Station, TX: Texas A&M University Press, 2003), p. 73.
[27]. Ibid., p. 73; for Rhode’s work on maneuver loads, see R.V. Rhode, “The Pressure Distribution over the Horizontal and Vertical Tail Surfaces of the F6C-4 Pursuit Airplane in Violent Maneuvers,” NACA TR-307 (1929).
[28]. For example, C.H. Dearborn and H.W. Kirschbaum, “Maneuverability Investigation of the F6C-3 Airplane with Special Flight Instruments,” NACA TR-369 (1932); and Philip Donely and Henry A. Pearson, “Flight and Wind-Tunnel Tests of an XBM-1 Dive Bomber,” NACA TN-644 (1938).
[29]. George W. Gray, Frontiers of Flight: the Story of NACA Research (New York: Alfred A. Knopf, 1948), p. 173.
[30]. Ibid., p. 174; Hansen, Engineer in Charge, p. 468. NACA researchers created the gust tunnel to provide information to verify basic concepts and theories. It ultimately became obsolete because of its low Reynolds and Mach number capabilities. After being used as a low-velocity instrument laboratory and noise research facility, the gust tunnel was dismantled in 1965.
[31]. Philip Donely, “Effective Gust Structure at Low Altitudes as Determined from the Reactions of an Airplane,” NACA TR-692 (1940); Walter G. Walker, “Summary of V-G Records Taken on Transport Airplanes from 1932 to 1942,” NACA WRL-453 (1942); Donely, “Frequency of Occurrence of Atmospheric Gusts and of Related Loads on Airplane Structures,” NACA WRL-121 (1944); Walker, “An Analysis of the Airspeeds and Normal Accelerations of Martin M-130 Airplanes in Commercial Transport Operation,” NACA TN-1693 (1948); and Walker, “An Analysis of the Airspeed and Normal Accelerations of Douglas DC-2 Airplanes in Commercial Transport Operations,” NACA TN-1754 (1948).
[32]. Donely, “Summary of Information Relating to Gust Loads on Airplanes,” NACA TR-997 (1950); Walker, “Gust Loads and Operating Airspeeds of One Type of Four-Engine Transport Airplane on Three Routes from 1949 to 1953,” NACA TN-3051 (1953); and Kermit G. Pratt and Walker, “A Revised Gust-Load Formula and a Re-Evaluation of V-G Data Taken on Civil Transport Airplanes from 1933 to 1950,” NACA TR-1206 (1954).
[33]. For example, E.T. Binckley and Jack Funk, “A Flight Investigation of the Effects of Compressibility on Applied Gust Loads,” NACA TN-1937 (1949); and Harvard Lomax, “Lift Developed on Unrestrained Rectangular Wings Entering Gusts at Subsonic and Supersonic Speeds,” NACA TN-2925 (1953).
[34]. Jack Funk and Richard H. Rhyne, “An Investigation of the Loads on the Vertical Tail of a Jet-Bomber Airplane Resulting from Flight Through Rough Air,” NACA TN-3741 (1956); Philip Donely, “Safe Flight in Rough Air,” NASA TMX-51662 (1964); W.H. Andrews, S.P. Butchart, T.R. Sisk, and D.L. Hughes, “Flight Tests Related to Jet-Transport Upset and Turbulent-Air Penetration,” and R.S. Bray and W.E. Larsen, “Simulator Investigations of the Problems of Flying a Swept-Wing Transport Aircraft in Heavy Turbulence,” both in NASA LRC, Conference on Aircraft Operating Problems, NASA SP-83 (1965); M. Sadoff, R.S. Bray, and W.H. Andrews, “Summary of NASA Research on Jet Transport Control Problems in Severe Turbulence,” AIAA Paper 65-330 (1965); and Richard J. Wasicko, “NASA Research Experience on Jet Aircraft Control Problems in Severe Turbulence,” NASA TM-X-60179 (1966).
[35]. Thomas L. Coleman and Emilie C. Coe, “Airplane Measurements of Atmospheric Turbulence for Altitudes Between 20,000 and 55,000 Feet Over the Western part of the United States,” NACA RM-L57G02 (1957); and Thomas L. Coleman and Roy Steiner, “Atmospheric Turbulence Measurements Obtained from Airplane Operations at Altitudes Between 20,000 and 75,000 Feet for Several Areas in the Northern Hemisphere,” NASA TN-D-548 (1960).
[36]. Eldon E. Kordes and Betty J. Love, “Preliminary Evaluation of XB-70 Airplane Encounters with High-Altitude Turbulence,” NASA TN-D-4209 (1967); L.J. Ehernberger and Betty J. Love, “High Altitude Gust Acceleration Environment as Experienced by a Supersonic Airplane,” NASA TN-D-7868 (1975). NASA’s supersonic cruise flight test research is the subject of an accompanying essay in this volume by William Flanagan, a former Air Force Blackbird navigator.
[37]. Joseph W. Jewel, Jr., “Tabulations of Recorded Gust and Maneuver Accelerations and Derived Gust Velocities for Airplanes in the NSA VGH General Aviation Program,” NASA TM-84660 (1983).
[38]. Robert W. Miller, “The Use of Airborne Navigational and Bombing Radars for Weather-Radar Operations and Verifications,” Bulletin of the American Meteorological Society, vol. 28, no. 1 (Jan. 1947), pp. 19–28; H. Press and E.T. Binckley, “A Preliminary Evaluation of the Use of Ground Radar for the Avoidance of Turbulent Clouds,” NACA TN-1864 (1948).
[39]. W. Frost and B. Crosby, “Investigations of Simulated Aircraft Flight Through Thunderstorm Outflows,” NASA CR-3052 (1978); Norbert Didden and Chi-Minh Ho, Department of Aerospace Engineering, University of Southern California, “Unsteady Separation in a Boundary Layer Produced by an Impinging Jet,” Journal of Fluid Mechanics, vol. 160 (1985), pp. 235–236.
[40]. See, for example, Paul A. Robinson, Roland L. Bowles, and Russell Targ, “The Detection and Measurement of Microburst Wind Shear by an Airborne Lidar System,” NASA LRC, NTRS Report 95A87798 (1993); Dan D. Vicroy, “A Simple, Analytical, Axisymmetric Microburst Model for Downdraft Estimation,” NASA TM-104053 (1991); and Vicroy, “Assessment of Microburst Models for Downdraft Estimation,” AIAA Paper 91-2947 (1991).
[41].Hansen, The Bird is on the Wing, p. 207.
[42]. William J. Cox, “The Multi-Dimensional Nature of Wind Shear Investigations,” in Society of Experimental Test Pilots, 1976 Report to the Aerospace Profession: Proceedings of the Twentieth Symposium of The Society of Experimental Test Pilots, Beverly Hills, CA, Sept. 22–25, 1976, vol. 13, no. 2 (Lancaster, CA: Society of Experimental Test Pilots, 1976).
[43]. National Transportation Safety Board, “Aircraft Accident Report: Iberia Lineas Aereas de España (Iberian Airlines), McDonnell-Douglas DC-10-30, EC CBN, Logan International Airport, Boston, Massachusetts, December 17, 1973,” Report NTSB-AAR-74-14 (Nov. 8, 1974).
[44]. “Aviation: A Fatal Case of Wind Shear,” Time (July 7, 1975); National Transportation Safety Board, “Aircraft Accident Report: Eastern Air Lines Inc. Boeing 727-225, N8845E, John F. Kennedy International Airport, Jamaica, New York, June 14, 1975,” Report NTSB-AAR-76-8 (Mar. 12, 1976); Edmund Preston, Troubled Passage: The Federal Aviation Administration during the Nixon-Ford Term, 1973–1977 (Washington, DC: FAA, 1987), p. 197.
[45]. U.S. National Transportation Safety Board, “Aircraft Accident Report: Continental Airlines Inc, Boeing 727-224, N88777, Stapleton International Airport, Denver, Colorado, August 7, 1975,” Report NTSB-AAR-76-14 (May 5, 1976).
[46]. National Transportation Safety Board, “Aircraft Accident Report: Allegheny Airlines, Inc., Douglas DC-9, N994VJ, Philadelphia, Pennsylvania, June 23, 1976,” Report NTSB-AAR-78-2 (Jan. 19, 1978).
[47]. For various perspectives on the multiagency research spawned by these accidents, see Amos A. Spady, Jr., Roland L. Bowles, and Herbert Schlickenmaier, eds., Airborne Wind Shear Detection and Warning Systems, Second Combined Manufacturers and Technological Conference, two parts, NASA CP-10050 (1990).
[48]. NASA Langley Research Center, “Windshear,” http://oea.larc.nasa.gov/PAIS/Windshear.html, accessed July 30, 2009.
[49]. Preston, Troubled Passage, p. 197.
[50]. Ibid., pp. 197–198; Cox, “Multi-Dimensional Nature,” pp. 141–142. Anemometers are tools that originated in the late Middle Ages and measure wind speed. The first anemometer, a deflection anemometer, was developed by Leonardo da Vinci. Several new varieties, including cup, pressure, and sonic anemometers, have emerged in the intervening centuries.
[51]. Dennis W. Camp, Walter Frost, and Pamela D. Parsley, Proceedings: Fifth Annual Workshop on Meteorological and Environmental Inputs to Aviation Systems, Mar. 31–Apr. 2, 1981, NASA CP-2192 (1981).
[52]. National Transportation Safety Board, “Aircraft Accident Report: Pan American World Airways, Clipper 759, N4737, Boeing 727-235, New Orleans International Airport, Kenner, Louisiana, July 9, 1982,” Report NTSB-AAR-83-02 (Mar. 21, 1983).
[53]. Ibid., p. ii.
[54]. “Wind Shear Study: Low-Altitude Wind Shear,” Aviation Week & Space Technology (Mar. 28, 1983), p. 32. One outcome was a seminal report completed before the end of the year by theNational Academy’s Committee on Low-Altitude Wind Shear and Its Hazard to Aviation, Low Altitude Wind Shear and Its Hazard to Aviation (Washington, DC: National Academy Press, 1983).
[55]. Sheldon Baron, Bolt Baranek, et al., Analysis of Response to Wind-Shears using the Optimal Control Model of the Human Operator, NASA Ames Research Center Technical Paper NAS2-0652 (Washington, DC: NASA, 1979).
[56]. J.R. Connell, et al., “Numeric and Fluid Dynamic Representation of Tornadic Double Vortex Thunderstorms,” NASA CR-171023 (1980).
[57]. National Academy of Sciences, Committee on Low-Altitude Wind Shear and Its Hazard to Aviation, Low Altitude Wind Shear and Its Hazard to Aviation (Washington, DC: National Academy Press, 1983), pp. 14–15; Roland L. Bowles, “Windshear Detection and Avoidance: Airborne Systems Survey,” Proceedings of the 29th IEEE Conference on Decision and Control, Honolulu, HI (New York: IEEE Publications, 1990), p. 708; H. Patrick Adamson, “Development of the Advance Warning Airborne System (AWAS),” paper presented at the Fourth Combined Manufacturers’ and Technologists’ Airborne Windshear Review Meeting, Turbulence Prediction Systems, Boulder, CO, Apr. 14, 1992. JAWS program research continued into the 1990s.
[58]. John McCarthy, “The Joint Airport Weather Studies (JAWS) Project,” in Camp, Frost, and Parsley, Proceedings: Fifth Annual Workshop on Meteorological and Environmental Inputs to Aviation, pp. 91–95; and Weneth D. Painter and Dennis W. Camp, “NASA B-57B Severe Storms Flight Program,” NASA TM-84921 (1983).
[59]. Center for Turbulence Research, Stanford University, “About the Center for Turbulence Research (CTR),” http://www.stanford.edu/group/ctr/about.html, accessed Oct. 3, 2009. For Illiac IV and its place in computing history, see Paul E. Ceruzzi, A History of Modern Computing (Cambridge: The MIT Press, 1999), pp. 196–197.
[60]. Chambers, Concept to Reality, p. 188.
[61]. National Transportation Safety Board, “Aircraft Accident Report: Delta Air Lines, Inc., Lockheed L-1011-385-1, N726DA, Dallas/Fort Worth International Airport, Texas, August 2, 1985,” Report NTSB-AAR-86-05 (Aug. 15, 1986). See also James Ott, “Inquiry Focuses on Wind Shear As Cause of Delta L-1011 Crash,” Aviation Week & Space Technology (Aug. 12, 1985), pp. 16–19; F. Caracena, R. Ortiz, and J. Augustine, “The Crash of Delta Flight 191 at Dallas-Fort Worth International Airport on 2 August 1985: Multiscale Analysis of Weather Conditions,” National Oceanic and Atmospheric Report TR