Runway Friction

8/13/2019 Runway Friction

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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 ConferenceMarch 1, 2006

Runway Friction Measurement &

Reporting Procedures


2/27

Why do airports measure friction ?

CFME or Decelerometer Why are theydifferent and which is more accurate?

Summer Testing Procedure

Winter Testing Procedure

Which CFME is Right for your Airport ?

Overview


3/27

Over time, the skid-resistance of runway pavementdeteriorates due to a number of factors:

The effect of these two factors are directly dependent uponthe volume and type of aircraft traffic.

Why do we measure Friction ?

mechanical wear and polishing action from aircrafttires rolling or braking on the runway surface

the accumulation of contaminants


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5/27

DC-9 Aircraft Wet Runway Landing Veer-off AccidentReynosa, Mexico; October 6, 2000



6/27

Chicago Midway Airport

Runw ay f r ic t ion w as acon t r ibu t ing fac to r



7/27


Initial Reported Comments Chicago Midway Airport

NTSB preliminary reports that the runway was last

cleared of snow and chemically de-iced approx. 45minutes prior to Southwest aircraft landing.

Airport officials reported the braking friction on the runwaywas good 30 minutes before the accident, but

investigators have determined the runway condition at thetime of the accident to be only fair to poor.


8/27

July / August 2005 two aircraft over ran the Runway, oneat Toronto and one at Bangladesh.

The Air France A-340 was destroyed in the post accidentfire. 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 completeloss of aircraft and 80 fatalities.



9/27

When a runway is contaminated with water theinformation passed to the pilot is reported as wet.

No water depth or location is reported.

During a heavy downpour, the conditions on the lengthof a runway can vary and may be deep enough to cause

hydroplaning.


A layer of water between the tires and the runwaysurface reduces the friction level to NIL braking action.


10/27

Typical Information given to the Pilot



11/27

C ontinuous F riction M easuring E quipment is thecontinuous 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

GriptesterNAC 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 AC150/5320-12C


12/27

C ontinuous F riction M easuring E quipment (CFME)

All approved CFMEs have different operating modes includingdifferent tires, tire inflation pressures, slip ratio, weights.

Each CFME will record different friction values atdifferent speeds as note in AC150/5320-12C, Table 3-2.

Info : FAA AC150/5320-12C, Table 3-2



13/27

A Decelerometer only gives a spot check of the pavement

BOWMONK

TAPLEY

TES ERD MK3VERICOM 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 MechanicalInfo : FAA AC150/5200-30A A endix 4

Is a CFME the same as a Decelerometers ?


14/27Info : Road Research Laborator Re ort 50


Slip WheelCFME 0.57

Locked WheelDecelerometer0.35

Effect of slip ratio on coefficient of braking friction on wet runway


15/27Info : FAA CERTALERT No. 05-01

Both Mu Value and Braking Action reporting isacceptable for reporting pavement conditions.

To date there is no correlation between CFME and aDecelerometer [1]


FACT

A CFME is a precision measurement device and is moreaccurate and reliable than a Decelerometer because of

several uncontrollable variables influencing thereporting (braking technique, vehicle condition, etc.) .


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SUMMER TESTING

AC150/5320-12C

Measurement, Construction and Maintenance of Skid-Resistant Airport Pavement Surfaces


17/27

Friction Evaluations with CFMEs are required by the FAA

Water is pumped directly in front of the frictionmeasuring wheel(s) at a controlled rate.

This gives standard repeatable conditions

This is an ideal test for monitoring rubber build up andthe runways micro and macro texture

Not an ideal test for monitoring ponding or in conditionssuch as Snow, Slush or Ice.

Summer Testing can only be performed using a CFME

Summer Testing

Info : FAA 150/5320-12C


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40mph Testing determines the overall Macrotexture /

Contaminant / Drainage condition of the PavementSurface.

60mph Testing determines the overall Micro-texture ofthe Pavement Surface

Tests give a good indication of the runway drainageability during rain conditions providing greaterinformation for winter OPS.

Summer Testing


19/27Info : FAA 150/5320-12C Pa e 19

TABLE 3-1 MINIMUM FRICTION SURVEYFREQUENCY

Summer Testing


20/27

Site Location ****

Runway Number 02-20Test Performed at 40mph

3 0 0

6 0 0

9 0 0

1 2 0 0

1 5 0 0

1 8 0 0

2 1 0 0

2 4 0 0

2 7 0 0

3 0 0 0

3 3 0 0

3 6 0 0

3 9 0 0

4 2 0 0

4 5 0 0

4 8 0 0

5 1 0 0

5 4 0 0

5 7 0 0

6 0 0 0

6 3 0 0

6 6 0 0

6 9 0 0

7 2 0 0

7 5 0 0

7 8 0 0

8 1 0 0

8 4 0 0

8 7 0 0

9 0 0 0

9 3 0 0

9 6 0 0

9 9 0 0

1 0 2 0

0

Runway Edge

18 0.62 0.46 0.44 0.45 0.53 0.53 0.41 0.50 0.53 0.54 0.50 0.59 0.62 0.63 0.66 0.61 0.66 0.66 0.73 0.71 0.75 0.88 0.86 0.88 0.90 0.92 0.88 0.94 0.90 0.86 0.82 0.79 0.71 0.5712 0.60 0.39 0.37 0.38 0.45 0.45 0.35 0.43 0.45 0.46 0.43 0.50 0.53 0.54 0.56 0.52 0.56 0.56 0.62 0.60 0.64 0.75 0.73 0.75 0.76 0.78 0.75 0.80 0.76 0.73 0.69 0.67 0.60 0.486 0.52 0.35 0.33 0.34 0.40 0.40 0.31 0.38 0.40 0.41 0.38 0.45 0.47 0.48 0.50 0.46 0.50 0.50 0.55 0.54 0.57 0.67 0.65 0.67 0.68 0.70 0.67 0.71 0.68 0.65 0.62 0.60 0.54 0.43

CL

6 0.56 0.42 0.36 0.37 0.44 0.44 0.34 0.42 0.44 0.45 0.42 0.50 0.52 0.53 0.55 0.51 0.55 0.55 0.61 0.59 0.63 0.74 0.72 0.74 0.75 0.77 0.74 0.78 0.75 0.72 0.68 0.66 0.59 0.4712 0.51 0.47 0.40 0.42 0.49 0.49 0.38 0.46 0.49 0.50 0.46 0.55 0.57 0.59 0.61 0.56 0.61 0.61 0.67 0.66 0.70 0.82 0.79 0.82 0.83 0.85 0.82 0.87 0.83 0.79 0.76 0.73 0.66 0.5318 0.53 0.52 0.45 0.46 0.55 0.55 0.42 0.52 0.55 0.56 0.52 0.62 0.64 0.66 0.68 0.63 0.68 0.68 0.75 0.74 0.78 0.92 0.89 0.92 0.93 0.96 0.92 0.97 0.93 0.89 0.85 0.82 0.74 0.59

Runway Edge

Predominant Landing direction

40mph TestKey Range Summer OP's Winter Op's

Nil 0.74-0.53

0.53-0.43


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Winter Testing

AC150/5200/30A

Airport Winter Safety and Operations


22/27

CFME are to be performed down the full length of therunway at a Safe Speed depending on runway conditions.

Decelerometer, a minimum of Three(3) Braking tests ineach zone are required in determining the average frictionvalue for that zone. A total of 9 braking tests areperformed.

Friction surveys will be reliable as long as the depth ofdry snow does not exceed 1 inch (25mm), or the depthof wet snow/slush does not exceed 1/8 (3mm) [1]

Info : FAA 150/5200-30 Page 11

Winter Testing


23/27

The central portion is contaminated over a distance of500 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

At least once(1) during eight(8) hour shift whilecontaminants are present.

Immediately following any aircraft incident or accidenton the runway.

Info : FAA 150/5200-30A, Page 11

Winter Testing


24/27

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

Location: 10 feet from centerline, in direction of aircraftlanding

Speed: Up to 40mph, as safety considerations allow

Info : FAA 150/5200-30A, Page 12

Winter Testing


25/27

CFME:

Friction Report using DFT RWY 03R, 34 -38-32,

compacted snow at 0325hrs.Decelerometer:

Friction Report using BOWMONK RWY 03R, 23 -27-21,

compacted snow at 0325hrs.Caution :

There is no correlation between a CFME and a Decelerometer [1]

Example Reporting for FSS & ATC

Info : FAA 150/5200-30A Pa e 12Ref 1 : FAA CERTALERT No. 05-01

Winter Testing

h h d h f


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Which device is right for your Airport?


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NEUBERT AERO CORP.

4105 West De Leon St., Tampa, FL 33609Phone: 727.538.8744 Fax: 727.538.8765

www.airportnac.com

* Copy of Presentation is available upon Request *

THANK YOU

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Runway Friction