Flugholm
You are correct, it does not really answer my questions. But we have a (ICAO) definition for
GOOD
Aeroplanes should not experience directional control or braking difficulties, especially when landing.
With respect to the braking action table some information can be found at
http://www.asft.se/history.html
From this you will se that the table was developed from about 3000 pilot reports. These were most probably piston driven aircrafts like Convair 440, DC-6, DC-7C and Saab 90 Scandia.
The actual braking action table was agreed upon in an meeting i Stockholm, Sweden 13 - 14 October 1959 and later found its way into the ICAO SNOWTAM-format. (Amendment 10 of Annex 15 - 1967/68)
gengis
Did your last two airliners distinguish between
- Poor as reported estimated surface friction/braking action or
- Poor as a measured or calculated coefficient (friction number)?