1 Aviation Wind Shear by Bob Jackson, MIC Seattle CWSU

2 Introduction Pilots do not always understand how the NWS uses particular terms, and when a term can/cannot be used in the preparation of forecasts. This presentation will show common mis-understandings of ‘WS’ terminology and applications.

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

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

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 “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 The results of both states were very similar.

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

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

11 How WS is Perceived Question 1 Is there a difference between ‘WS’ and ‘Micro-burst’? X

12 Difference between WS & Micro-burst?

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? X

14 Does LLWA Indicate Micro-burst?

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

16 Does WS = Micro-burst?

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

18 Does ‘WS’ = ‘LLWA’?

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

20 Recovery Procedures

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 X

22 Micro-burst in TAF?

23 How WS is Perceived Question 7 Is turbulence always experienced when encountering a micro-burst? X

24 Does Micro-burst = Turbulence?

25 How WS is Perceived Discussion - 1 The 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 How WS is Perceived Discussion - 2 Only 2% of Pilots and Only 14% of the Meteorologists Answered all of the questions correctly.

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 How WS is Perceived Discussion - 4 Only 1/2 of the meteorologists knew that the term “WS” in a TAF Does not mean that Micro-bursts are expected. Less than 1/4 of the Pilots knew.

29 How WS is Perceived Discussion % of Pilots and 5% of the Meteorologists answered all questions wrong, or didn’t know.

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 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 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 Why the Confusion? Described as: “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 Why the Confusion? An example of an FAA training material

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 In Closing Most pilots and many forecasters do not fully understand the ‘WS’ and Micro-burst elements that can be included in TAFs. Do You?

37 The End Of Part One