SH 5

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The Why and How of Runway Friction
Testing by Delia Harverson Findlay Irvine
Ltd. Midlothian, Scotland and Thomas J.
Yager NASA Langley Research Center Hampton, VA,
USA Part 1 A Brief History
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runway friction testing history

• What were the first Continuous reading Friction
  Measuring Equipments
• CFMEs
• ?
• When were they introduced
• ?

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The first CFME was the Skiddometer
designed in Sweden in the late 1950s
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the second CFME
was the
designed by the UK Ministry of Defence in the
early 1960s
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Why were these early CFMEs developed?
1962 a Canberra lands on a winter contaminated
runway ...
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and comes safely to a stop
The first CFMEs were developed mainly for testing
in winter conditions
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After the Skiddometer and the MuMeter came the
Saab Friction Tester
which was also originally designed to measure in
winter conditions
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Later CFMEs were designed as much for maintenance
testing as for operational testing
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question

• Is it as important to measure runway friction in
  summer as in winter?
• YES!
• In rain, a runway with poor texture and rubber
  deposits can be just as slippery as a runway
  contaminated with ice and snow

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An accident waiting to happen
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another question

• Are there more overrun accidents on wet runways
  or on runways contaminated with ice and snow?
• There are substantially more overrun accidents on
  wet runways
• Most of these accidents need never have happened

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runway friction testing

• Nothing will guarantee that an overrun accident
  wont happen at your airport

but regular use of an approved, well maintained
CFME will make it less likely
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operational maintenancetesting

• Operational testing is carried out in natural
  conditions, in winter, in order to make immediate
  operational decisions.
• Maintenance testing is carried out in carefully
  controlled conditions, which include an exact
  amount of water put down in front of the
  measuring wheel, in order to make engineering
  decisions.

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operational maintenancetesting

• Should engineering decisions ever be made on the
  basis of operational testing?
• No!
• Natural conditions are much too variable to
  provide a proper basis for engineering decisions

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runway friction testing

• How do we ensure that maintenance friction
  testing is consistent
• that the same results are obtained in Lima as
  in London Heathrow?
• in Santa Cruz as in Singapore?

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runway friction testing

• For this, the international community depends on
• ICAO

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runway friction testing
Before we get onto ICAOs role, two quick words
about the lunch-box test

• Forget it!