In accordance with ICAO standards, the French rules require aerodrome operators to assess regularly intrinsic friction characteristics of runway using a self-wetting continuous friction-measuring equipment (CFME).
French rules define a minimum friction level, below which the runway is considered as slippery, corrective actions have to be taken to improve runway friction characteristics and pilots have to be informed of such conditions.
All self-wetting CFMEs used for construction and maintenance purposes on French airports have to be certified by the State. The certification intends to ensure aerodrome operator that the CFME performs with reliability and consistency. It also harmonizes friction values between different devices and ensures a uniform acceptance of the minimum friction level.
The certification process consists in correlation trials between the applicant device and the reference device, owned by the French Civil Aviation Technical Centre (STAC). The performances of the applicant device in terms of repeatability and consistency of friction measurements are checked.
A device reaching requirements for certification is then correlated to the reference device of the same type and is delivered with a certificate. This certificate is valid for two years and must be renewed at the end of this period.