Aviation Wind Shear

1. 1 Aviation Wind Shear Bob Jackson, MIC, ZSE CWSU There is a recurring need to keep Low Level Wind Shear (LLWS), Wind Shear (WS), Micro-bursts, and turbulence a low levels in the mind of forecasters and pilots. This presentation attempts to fulfill that need.There is a recurring need to keep Low Level Wind Shear (LLWS), Wind Shear (WS), Micro-bursts, and turbulence a low levels in the mind of forecasters and pilots. This presentation attempts to fulfill that need.

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3. 3 Main Goals: Help forecasters realize short-comings in terminology of Wind-shear Improve awareness and understanding of proper application of Wind Shear in TAFs

4. 4 This Presentation Discusses: How the pilots perceive WS How many meteorologists perceive WS

5. 5 How Pilots perceive WS �Forecasters tend to believe that pilots know more about weather than they actually do.� (R. Jackson) Two Studies by R. Jackson demonstrate pilot�s lack of knowledge of Wind Shear: �Low-Level Wind Shear Terminology� �A Comparative Study of Pilot�s Understanding of Low-Level Wind Shear Terminology�

6. 6 �Low-Level Wind Shear Terminology� Survey taken by Certified Flight Instructors in Washington State in 1991. Presented at the �Fourth International Conference on Aviation Weather Systems� June 24-28 1991, in Paris, France Printed in Post-Print Proceedings Volume, pp13-15 by AMS and French Met. Society.

7. 7 �Low-Level Wind Shear Terminology� It was suggested that pilots in Washington may not be as aware of WS terminology because of less convective activity than in other states, So a second survey was taken in Texas.

8. 8 �A Comparative Study of Pilot�s understanding of Low-Level Wind Shear Terminology� Results of same survey taken by Certified Flight Instructors in Texas, July 1991. The results of both states were very similar.

9. 9 Delivered to AMS/NWS Aviation Weather Conference, Kansas City, Dec 1991, and printed in post-print volume. Meteorologists at the conference also took survey. �A Comparative Study of Pilot�s understanding of Low-Level Wind Shear Terminology�

10. 10 The Survey Participants were asked not to guess��If you don�t know, please indicate in appropriate space.�

11. 11 How WS is Perceived Question 1 Is there a difference between �WS� and �Micro-burst�?

12. 12 Difference between WS & Micro-burst?

13. 13 How WS is Perceived Question 2 �You are on approach and are told that there is a LLWA in effect. Would you expect micro-burst activity in the area?

14. 14 Does LLWA Indicate Micro-burst?

15. 15 How WS is Perceived Question 3 If you see WS mentioned in the TAF, Would you expect Micro-burst activity in the area?

16. 16 Does WS = Micro-burst?

17. 17 How WS is Perceived Question 4 Does �WS� in the TAF and �LLWA� given by tower mean the same thing?

18. 18 Does �WS� = �LLWA�?

19. 19 How WS is Perceived Question 5 Is the recovery procedure the same for WS as it is for the micro-burst?

20. 20 Recovery Procedures

21. 21 How WS is Perceived Question 6 If micro-burst is expected to occur in terminal area, How would it be indicated in the TAF? A. WS B. +TRW VRB50G55 C. Don�t know / Unsure

22. 22 Micro-burst in TAF?

23. 23 How WS is Perceived Question 7 Is a micro-burst always accompanied by turbulence?

24. 24 Does Micro-burst = Turbulence?

25. 25 How WS is Perceived Discussion - 1 Majority knew WS and Micro-burst were different (Question 1) Less than 1/3 of the pilots knew recovery procedure was different for each phenomenon

26. 26 How WS is Perceived Discussion - 2 Only 2% of Pilots and Only 14% of the Meteorologists Answered all of the questions correctly.

27. 27 How WS is Perceived Discussion - 3 Nearly 80% of pilots did not know how micro-bursts are identified in TAFs, Nearly 60% of responding �aviation experts� didn�t know.

28. 28 How WS is Perceived Discussion - 4 Only 1/2 of the �aviation experts� know that the term �WS� in a TAF Does not mean that Micro-bursts are expected. Less than 1/4 of the Pilots knew.

29. 29 How WS is Perceived Discussion - 5 13% of Pilots and 5% of the Meteorologists answered all questions wrong, or didn�t know.

30. 30 How WS is Perceived Discussion - 6 If a 70% score was needed for a passing grade, 90% of the pilots would have failed. 42% of the meteorologists would have failed. (Not all of the meteorologists were forecasters.)

31. 31 Why the Confusion? Most training materials do not differentiate between Convective and Mechanical WS. The term �Wind shear� has been used interchangeably with Micro-bursts by: FAA - in training and investigations NCAR - training materials NTSB - in accident investigations MEDIA - reporting aircraft accidents

32. 32 Why the Confusion? As an example, �The Probable Cause - Wind Shear� , NCAR, 1884 By NCAR for the FAA Training Video �Geared toward alerting pilots to Wind-Shear�� Actually discussed an aircraft accident involving Micro-burst.

33. 33 Why the Confusion? �The Wind Shear Factor� , NCAR, 1886 By NCAR for the FAA �Training Video geared toward pilots and traffic controllers to Wind-Shear�� Discussed Micro-bursts.

34. 34 Why the Confusion? An example of an FAA training material

35. 35 Why the Confusion? A system designed to detect Micro-bursts is called The �Low Level Wind Shear Alert system� (LLWAS) When a Micro-burst is detected, then A Low Level Wind Shear Alert (LLWA) is issued, warning of a Micro-burst.

36. 36 In Closing Most pilots and many forecasters do not fully understand the �WS� and Micro-burst elements that can be included in TAFs.

37. 37 The End Of Part One