alf5071h
Your questions are absolutely to the point.
The most important thing is that we "speak the same language".
The information gathered by the "ground staff" must be understood by both parties and transmitted to the pilot as speedily and accurately as possible.
I am involved in a couple of projects dealing with these questions, and yes I want the industry to look with me. There is a lot of experience out there - good experience. One difficulty is that the focus on the measured friction coefficient have "masked" the knowledge and use of the descriptive terms, therefore my questions and search.
The comment: There is no overall accepted ...... is still valid. And that it is not only for the my-meter. The outcome from the JWRFMP found a better correlation between aircraft performance and decelerometer type of measuring instrument then for those of fixed or variable slip type.
New friction measurement devices enter the marked every year - they claim to be better than the previous - but they add to the complexity and confusion and frustration - and the result is that there is even a bigger need for harmonisation - timeless. In the early 60's ICAO was told that the accuracy of the measurements was 0.01. Today we know that not to be true. It is more close to 0.1. (repeatability and reproducibility). ICAO (study groups) also had difficulties with harmonisation between two types of instruments in the early 60's. There were an ICAO harmonisation project in the 70's with several instruments. NASA have looked into the subject. The last major project was the JWRFMP administrated by Transport Canada. One outcome was the update of the Canadian Runway Friction Index - CRFI. Finnair has also made use of results from JWRFMP for their operations. One thing in common for both Canada and Finland - they have standardised on one single type of friction measurement device. Canada a decelerometer, Finland av fixed slip device.