Results of the Boeing Company Wake Turbulence Test Program

  • P. M. Condit
  • P. W. Tracy


The development of large jet transport airplanes led to concern that the turbulent wakes generated by these aircraft would create a hazard for other air traffic. The Boeing Company initiated a study of large jet airplane wake turbulence in mid 1969. The Boeing flight test program was undertaken to evaluate the behavior of trailing vortices and to obtain a direct comparison between the turbulent wakes of the 747 and a 707-320C. A fully instrumented Boeing 737–100 was used as the primary wake probing aircraft. Additional probes were made with the Boeing owned F-86 and NASA’s CV990. The 737 was also flown in the turbulent wake of the 747 on approach to landing in order to assess the effects of wake turbulence near the ground. These tests produced several significant conclusions. It was found that the dynamic response of the chase airplanes (737, CV990, F-86) was essentially the same when flying in the turbulent wakes of either the 747 or 707. Thus the wakes of large jet airplanes (747 and C-5A) do not represent a significant new hazard for other air traffic. The turbulent wake was expected to descend behind the generating airplane at a constant rate until fully dissipated. It was observed, however, that the wake leveled off and never descended more than 900 feet below the generating airplane. This indicates that in level flight, airplanes should be separated vertically by approximately 1000 feet in order to avoid wake turbulence. In the approach and landing tests it was found that the wake generated in ground effect does not “roll up” into strong trailing vortices. Consequently, wake turbulence is relatively weak near the runway in the landing flare and takeoff rotation areas. Recommendations are presented for air traffic regulations which will virtually eliminate hazardous wake turbulence encounters.


Vortex Wake Wake Turbulence Bank Angle Roll Rate BOEING Company 
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Copyright information

© Plenum Press, New York 1971

Authors and Affiliations

  • P. M. Condit
    • 1
  • P. W. Tracy
    • 1
  1. 1.Commercial Airplane DivisionThe Boeing CompanyUSA

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