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Presented by: Timothy W. Neubert, MBA, A.A.E., Neubert Aero Corp. Barry Goff, BEng. Research & Development, NAC Dynamics, LLC. 29 th Annual Airport Conference.

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Presentation on theme: "Presented by: Timothy W. Neubert, MBA, A.A.E., Neubert Aero Corp. Barry Goff, BEng. Research & Development, NAC Dynamics, LLC. 29 th Annual Airport Conference."— Presentation transcript:

1 Presented by: Timothy W. Neubert, MBA, A.A.E., Neubert Aero Corp. Barry Goff, BEng. Research & Development, NAC Dynamics, LLC. 29 th Annual Airport Conference March 1, 2006 Runway Friction Measurement & Reporting Procedures

2  Why do airports measure friction ?  CFME or Decelerometer – Why are they different and which is more accurate?  Summer Testing – Procedure  Winter Testing – Procedure  Which CFME is Right for your Airport ? Overview

3 Over time, the skid-resistance of runway pavement deteriorates due to a number of factors: The effect of these two factors are directly dependent upon the volume and type of aircraft traffic. Why do we measure Friction ? mechanical wear and polishing action from aircraft tires rolling or braking on the runway surfacemechanical wear and polishing action from aircraft tires rolling or braking on the runway surface the accumulation of contaminantsthe accumulation of contaminants

4 Runway Contaminants, such as, rubber deposits, dust particles, jet fuel, oil spillage, water, snow, ice, and slush, all cause friction loss on runway pavement surfaces. The most persistent contaminant problem is rubber deposit from tires of landing jet aircraft. Rubber deposits occur at the runway touchdown areas and is extensive to remove. NOTE: Friction testing is required before and after rubber removal. Heavy rubber deposits can completely cover the pavement surface texture causing loss of aircraft braking capability and directional control, particularly when runways are wet. Why do we measure Friction ?

5 DC-9 Aircraft Wet Runway Landing Veer-off Accident Reynosa, Mexico; October 6, 2000 Why do we measure Friction ?

6 Chicago Midway Airport Chicago Midway Airport Runway friction was a contributing factor Why do we measure Friction ?

7 Initial Reported Comments – Chicago Midway Airport NTSB preliminary reports that the runway was last cleared of snow and chemically de-iced approx. 45 minutes prior to Southwest aircraft landing. Airport officials reported the braking friction on the runway was “good” 30 minutes before the accident, but investigators have determined the runway condition at the time of the accident to be only “fair” to “poor”.

8 July / August 2005 two aircraft over ran the Runway, one at Toronto and one at Bangladesh. The Air France A-340 was destroyed in the post accident fire. Both accidents involved landings in heavy rain and crosswinds conditions. According to Accident Records: During the last 15 years, there have been 130 accidents involving aircraft overruns and runway veer-offs, of which 3 resulting in complete loss of aircraft and 80 fatalities. Why do we measure Friction ?

9 When a runway is contaminated with water the information passed to the pilot is reported as “wet”. No water depth or location is reported. During a heavy downpour, the conditions on the length of a runway can vary and may be deep enough to cause hydroplaning. Why do we measure Friction ? A layer of water between the tires and the runway surface reduces the friction level to NIL braking action.

10 Typical Information given to the Pilot Why do we measure Friction ?

11 Continuous Friction Measuring Equipment is the continuous trace of friction along the length of the runway Is a CFME the same as a Decelerometer? Airport Surface Friction Tester Mu Meter Runway Friction Tester Griptester NAC Dynamic Friction Tester RUNAR Runway Analyser and Recorder BV-11 Sarsys Friction Tester The “Mu Value” is calculated by the horizontal force divided by the vertical force or by using the measured torque generated at the measuring tire. Info : FAA AC150/ C

12 Continuous Friction Measuring Equipment (CFME) All approved CFME’s have different operating modes including different tires, tire inflation pressures, slip ratio, weights. Each CFME will record different friction values at different speeds as note in AC150/ C, Table 3-2. Info : FAA AC150/ C, Table 3-2 Is a CFME the same as a Decelerometer?

13 A Decelerometer only gives a spot check of the pavement BOWMONKTAPLEY TES ERD MK3 VERICOM VC3000 RFM The operation of a Decelerometer is to measure the forces generated in terms of g (deceleration ft/sec 2 ) “under full skid conditions”. Decelerometers can be either Electronic or Mechanical Info : FAA AC150/ A Appendix 4 Is a CFME the same as a Decelerometers ?

14 Info : Road Research Laboratory Report 50 Is a CFME the same as a Decelerometer? Slip Wheel CFME 0.57µ Locked Wheel Decelerometer 0.35µ Effect of slip ratio on coefficient of braking friction on wet runway

15 Info : FAA CERTALERT No Both Mu Value and Braking Action reporting is acceptable for reporting pavement conditions. To date there is no correlation between CFME and a Decelerometer [1] To date there is no correlation between CFME and a Decelerometer [1] Is a CFME the same as a Decelerometer? FACT A CFME is a precision measurement device and is more accurate and reliable than a Decelerometer because of several uncontrollable variables influencing the reporting (braking technique, vehicle condition, etc.).

16 SUMMER TESTING AC150/ C Measurement, Construction and Maintenance of Skid- Resistant Airport Pavement Surfaces

17 Friction Evaluations with CFME’s are required by the FAA Friction Evaluations with CFME’s are required by the FAA Water is pumped directly in front of the friction measuring wheel(s) at a controlled rate. This gives standard repeatable conditions This is an ideal test for monitoring rubber build up and the runways micro and macro texture Not an ideal test for monitoring ponding or in conditions such as Snow, Slush or Ice. Summer Testing can only be performed using a CFME Summer Testing Info : FAA 150/ C

18 40mph Testing determines the overall Macrotexture / Contaminant / Drainage condition of the Pavement Surface. 40mph Testing determines the overall Macrotexture / Contaminant / Drainage condition of the Pavement Surface. 60mph Testing determines the overall Micro-texture of the Pavement Surface Tests give a good indication of the runway drainage ability during rain conditions providing greater information for winter OPS. Tests give a good indication of the runway drainage ability during rain conditions providing greater information for winter OPS. Summer Testing

19 Info : FAA 150/ C Page 19 TABLE 3-1 MINIMUM FRICTION SURVEY FREQUENCY Summer Testing

20 Friction / Distance 2D Charting Runway divided in to 300 foot sections and color coded for quick reference Summer Testing

21 Winter Testing AC150/5200/30A Airport Winter Safety and Operations

22 CFME are to be performed down the full length of the runway at a Safe Speed depending on runway conditions. CFME are to be performed down the full length of the runway at a Safe Speed depending on runway conditions. Decelerometer, a minimum of Three(3) Braking tests in each zone are required in determining the average friction value for that zone. A total of 9 braking tests are performed. Decelerometer, a minimum of Three(3) Braking tests in each zone are required in determining the average friction value for that zone. A total of 9 braking tests are performed. Friction surveys will be reliable as long as the depth of dry snow does not exceed 1 inch (25mm), or the depth of wet snow/slush does not exceed 1/8” (3mm) [1] Friction surveys will be reliable as long as the depth of dry snow does not exceed 1 inch (25mm), or the depth of wet snow/slush does not exceed 1/8” (3mm) [1] Info : FAA 150/ Page 11 Winter Testing

23 The central portion is contaminated over a distance of 500 feet (150m) or more. Whenever visual runway inspections or pilot reports changing friction characteristics. Friction Surveys are to be performed when: Following anti-icing, de-icing, or sanding operations Following anti-icing, de-icing, or sanding operations At least once(1) during eight(8) hour shift while contaminants are present. At least once(1) during eight(8) hour shift while contaminants are present. Immediately following any aircraft incident or accident on the runway. Immediately following any aircraft incident or accident on the runway. Info : FAA 150/ A, Page 11 Winter Testing

24 Calibration: In accordance with the operating manual Coordination: Work closely with ATC/FSS Friction Measuring Procedures (C.C.C.L.S): Clearance: contact ATC/FSS Clearance: contact ATC/FSS Location: 10 feet from centerline, in direction of aircraft landing Location: 10 feet from centerline, in direction of aircraft landing Speed: Up to 40mph, as safety considerations allow Speed: Up to 40mph, as safety considerations allow Info : FAA 150/ A, Page 12 Winter Testing

25 CFME: Friction Report using “DFT RWY 03R, , compacted snow at 0325hrs. Decelerometer: Friction Report using “BOWMONK RWY 03R, , compacted snow at 0325hrs. Caution : There is no correlation between a CFME and a Decelerometer [1] Example Reporting for FSS & ATC Info : FAA 150/ A Page 12 Ref [1] : FAA CERTALERT No Winter Testing

26 Which device is right for your Airport?

27 NEUBERT AERO CORP West De Leon St., Tampa, FL Phone: Fax: * Copy of Presentation is available upon Request * THANK YOU


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