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LWE and Checktime Demo LWE and Checktime Demo Scott Landolt & Steve Cristanelli - NCAR October 27, 2009

LWE and Checktime Demo

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LWE and Checktime Demo. Scott Landolt & Steve Cristanelli - NCAR October 27, 2009. What is LWE, Checktime and WSDDM?. LWE – Liquid Water Equivalent Checktime – Automated Holdover Time (HOT) Algorithm WSDDM – Weather System for De-icing Decision Making. Why use LWE?. - PowerPoint PPT Presentation

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Page 1: LWE and  Checktime  Demo

LWE and Checktime DemoLWE and Checktime Demo

Scott Landolt & Steve Cristanelli - NCAROctober 27, 2009

Page 2: LWE and  Checktime  Demo

What is LWE, Checktime and WSDDM?

• LWE – Liquid Water Equivalent

• Checktime – Automated Holdover Time (HOT) Algorithm

• WSDDM – Weather System for De-icing Decision Making

Page 3: LWE and  Checktime  Demo

Why use LWE?

Page 4: LWE and  Checktime  Demo

Precipitation Type sensor (HSS)

WXT temperature, humidity, and wind sensor (Vaisala)

Hotplate (Yankee) Weighing Snowgauge

(GEONOR)

Liquid WaterEquivalent System Components

Precipitation Type sensor (Vaisala PWD-22)

Freezing Rain sensor (Campbell)

Page 5: LWE and  Checktime  Demo

Chicago Instrumentation Chicago Instrumentation LocationLocation

X

ASOS site LWE site

Page 6: LWE and  Checktime  Demo

LWE Display DemoLWE Display Demo

Page 7: LWE and  Checktime  Demo

Marshall Field Site testing FY08Marshall Field Site testing FY08

List the dates that obtained data for List the dates that obtained data for including the number of hours:including the number of hours:

DateDate Hours of Hours of datadata

Nov. 11, 2007Nov. 11, 2007 66Dec. 20 2007Dec. 20 2007 55

Total hours: Total hours: 144144

Thank you

Wind Enhancement of LWE due to 10 degree angle of a wing

Based on paper in Journal of Aircraft: “Common Snowfall Conditions Associated with Aircraft Takeoff Accidents”,Rasmussen et al. (2000)

Page 8: LWE and  Checktime  Demo

Marshall Field Site testing FY08Marshall Field Site testing FY08

List the dates that obtained data for List the dates that obtained data for including the number of hours:including the number of hours:

DateDate Hours of Hours of datadata

Nov. 11, 2007Nov. 11, 2007 66Dec. 20 2007Dec. 20 2007 55

Total hours: Total hours: 144144

Insert image of snow pans

Thank you

Wind Enhancement of LWE due to 10 degree angle of wing: 10º pan compared to 0º pan using error rejection

criteria

Based on paper in Journal of Aircraft: “Common Snowfall Conditions Associated with Aircraft Takeoff Accidents”,Rasmussen et al. (2000)

Factor of 1.8 larger snow

catch on a 10 degree surface

for a wind speed of 6 m/s

Page 9: LWE and  Checktime  Demo

Snow rate

Wind enhanced rate

Raw precipitation rate

Page 10: LWE and  Checktime  Demo

http://www.rap.ucar.edu/projects/winter/CLE

Online Cleveland LWE display URL

Page 11: LWE and  Checktime  Demo

How does LWE relate to Checktime?

Page 12: LWE and  Checktime  Demo

Inputs to Check Time: 1. Precipitation rate (every minute) enhanced by wind (10 degree effect)

2. Wind speed (every minute)

3. Temperature (every minute)

4. Precipitation type (every minute)

5. Fluid type and concentration

6. Regression equations that relate holdover time to precipitation rate and ambient temperature (from APS report)

Output:

Fluid Expiration time every minute (wall clock time, or Check Time) for given fluid type and concentration

Page 13: LWE and  Checktime  Demo

Checktime Display

Page 14: LWE and  Checktime  Demo

Checktime Display

Page 15: LWE and  Checktime  Demo

Radio MessageRadio Message

At 1630 local, temperature -3C, Light Snow, At 1630 local, temperature -3C, Light Snow, Checktime for Type IV Kilfrost ABC-S Plus Checktime for Type IV Kilfrost ABC-S Plus is 16:50is 16:50

Page 16: LWE and  Checktime  Demo

Impact of Time Variation of Precipitation Impact of Time Variation of Precipitation Rate, Temperature, and Wind Speed on Rate, Temperature, and Wind Speed on

Holdover TimeHoldover Time Data from Denver, Chicago and Pittsburgh all Data from Denver, Chicago and Pittsburgh all

showed that time variation of precipitation has showed that time variation of precipitation has a significant effect on Holdover Timea significant effect on Holdover Time– On average, 50% of the Instantaneous HOTs On average, 50% of the Instantaneous HOTs

longer than Check Time HOTs.longer than Check Time HOTs.– 15% of the Instantaneous HOTs a factor of 1.25 15% of the Instantaneous HOTs a factor of 1.25

longer than Check Time HOTs (a potential safety longer than Check Time HOTs (a potential safety issue). issue).

– 5% of the Instantaneous HOTs a factor of 1.5 long 5% of the Instantaneous HOTs a factor of 1.5 long than Check Time HOTsthan Check Time HOTs

Page 17: LWE and  Checktime  Demo

2008/2009 User Feedback2008/2009 User Feedback DenverDenver

– LWE rates found to accurately reflect operational experience: LWE rates found to accurately reflect operational experience: Example: LWE system reporting of heavy snow during the April 17Example: LWE system reporting of heavy snow during the April 17 thth

event confirmed due to the repeated deicing of 757 aircraft (4 times), event confirmed due to the repeated deicing of 757 aircraft (4 times), and return for deicing a fifth time. and return for deicing a fifth time.

– Found the precipitation type reporting on LWE to be useful. Found the precipitation type reporting on LWE to be useful.

– Tend to use Check Time over LWE system due to the direct Tend to use Check Time over LWE system due to the direct reporting of current Holdover time (expiration time) and more reporting of current Holdover time (expiration time) and more accurate HOT (than instantaneous).accurate HOT (than instantaneous).

– Used the Check Time system to determine when to transition Used the Check Time system to determine when to transition from Type I only to two step Type I and Type IV operationfrom Type I only to two step Type I and Type IV operation

Page 18: LWE and  Checktime  Demo

Current StatusCurrent Status• User feedback positive with regard to the useability and usefulness of the snow LWE. More feedback desired, however. • Users asking to use the systems operationally. • Before can, however, need the FAA to approve.

Remaining Issues:1. Communication to the pilot

- Majority of users prefer message via radio frequency.- Radio frequencies hard to get at airports. - Display on the web.- Product on a Blackberry

2. Approval of LWE snow system for operational use. FAA working on.

3. Expansion to include other precipitation types - Freezing rain and drizzle (2008-2009)- Ice pellets (2009-2010)

4. Approval of Check Time system for operational use.

Page 19: LWE and  Checktime  Demo

SurveySurvey

ATIS – Current time is _____ATIS – Current time is _____– Visibility __________Visibility __________– Temperature ______Temperature ______

Current System HOT Current System HOT – Snow Intensity Chart ________Snow Intensity Chart ________– HOT _________HOT _________

Page 20: LWE and  Checktime  Demo

SurveySurvey LWE (Radio Frequency)LWE (Radio Frequency)

– Temperature _______ Temperature _______ – Intensity __________Intensity __________– HOT (Volume 1 holdover chart) ______HOT (Volume 1 holdover chart) ______

Checktime (Radio Frequency)Checktime (Radio Frequency)– Start time of Type IV ________Start time of Type IV ________– Checktime _________Checktime _________– As close to runway as possible, new checktime As close to runway as possible, new checktime

______, Current time ____________, Current time ______

Page 21: LWE and  Checktime  Demo

SurveySurvey

Did you have to return for De-icing?Did you have to return for De-icing?– If yes, answer these questionsIf yes, answer these questions

Did the time expire? _____Did the time expire? _____ Was the fluid contaminated? _____Was the fluid contaminated? _____ Preemptive? _____Preemptive? _____

Additional training and/or feedback can be found at – http://www.rap.ucar.edu/projects/winter/ORD

Page 22: LWE and  Checktime  Demo

WSDDM