Slant Range
The actual straight line distance between an aircraft in flight and a ground location (radar, DME).
This distance is greater than the geographical surface range because of the altitude.
Slant Range Error
Slant range error is the difference between the distance of an aircraft (Point A) to a DNE station on the surface (Point B) and the distance from the station (Point B) to a point directly beneath the aircraft on the surface (Point C). The error magnitude is a function of aircraft altitude above the station and the distance to the station.
Sliding-Window Model
Rather than a specific date or time, the mean or average figure across a range of days, weeks, months or years is used. Typically a 3-5 year period may be used and the mean or average figure for that period is then applied to the problem. Tends to remove extreme peaks (positive or negative).
SNOWTAM
Message containing snow fall information; A special series NOTAM notifying the presence or removal of hazardous conditions due to snow, ice, slush or standing water associated with snow, slush and ice on the movement area, by means of a specific format.
SNOWTAM : A special series NOTAM notifying the presence or removal of hazardous conditions due to snow, ice, slush or standing water associated with snow, slush and ice on the movement area, by means of a specific format (ICAO 8400/4)
Soft Approach
A specific approach to systems theory that starts with utter confusion and little clarity or understanding and which progresses through rich pictures and iterative loops until improved clarity (or consensus) is obtained by the parties concerned.