Tas And Sas - Larsen & Brusgaard ALTITRACK Manual

18 - TAS and SAS

Definitions
True Airspeed (TAS) and Skydiver's Airspeed (SAS) are two methods of calculating
the airspeed of a moving/flying/falling object.
TAS is a term used in aviation: It is the speed of an object relative to the
surrounding air, regardless of the altitude.
SAS is a new concept developed by LARSEN & BRUSGAARD: SAS is the speed of
a skydiver calculated from measurements of air pressure and temperature and
converted to a fixed air pressure (875.3 mb) and a fixed temperature (+7.080C)
which corresponds to 4,000 feet ASL.
TAS
A skydiver's True Airspeed (TAS) relative to the ground changes as a function of the
altitude (air pressure) and temperature which makes it difficult to compare fall-
rates.
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