Good - Fair - Poor - Nil
In the NTSB special investigation report NTSB/SIR-83/02 we find following definitions of pilots terms: (These definitions are from the 1980 edition of the Air Transport Association's Snow Removal Handbbook.)
GOOD
More braking is available than will be used in an average airline type deceleration. If a max energy stop were attempted, some distance in excess of certified stopping distance would be expected.
FAIR
Sufficient braking and cornering force is available for a well flown approach and landing using light braking. However, excess speed or long touchdown would result in an extremely low safety factor depending on runway length and crosswind component. Careful planning and good judgement are required.
POOR
Very careful planning, judgement and execution are absolutely essential. Crosswind becomes a "priority one" consideration. While a safe and successful approach, landing and stop can be accomplished if all factors are favorable, there is little room for error. Care must be exercised in every facet of the operation and a very careful evaluation of all existing conditions is necessary.
NIL
Extremey slippery with poor directional control even while taxiing. This is the kind of report we would envision during a freezing rain condition if nothing were done to the runways or taxiways.
Are these definitions still valid?
Are there other definitions for GOOD - FAIR - POOR - NIL in operational use?