Geopotential Tables

Much time and effort has been given to the Geopotential Tables of Airspeed, altitude and Mach number based on incorporation of the physical constants and atmospheric properties adopted for the Internation'l Civil Aviation Organization (ICAO) standard atmosphere. These tables were derived by N.A.S.A at Langley Field and the Internat'l Civil Aviation Organization (ICAO). In the Tables, values of impact pressure are given for airspeeds up to 1000 knots and 100 miles/hr. Pressure-altitude tables, extracted from the ICAO standard atmosphere, are given for altitudes up to 100,000 geopotential feet. With the latest information concerning atmospheric properties (particularly at the higher altitudes) this new unit of height (Geopotential Feet) takes into account the decrease of the gravity constant with height. For the determination of MACH number, the ratio of impact pressure to free-stream static pressure is given for MACH numbers from 0.10 to 5.00.

Pressure-airspeed and pressure-altitude tables are needed for the calibration of airspeed meters and altimeters and for the conversion of flight measurements of airspeed and altitude to other related parameters – Alt, in feet/meter; psi; inHg; P(mb); voltage, with similar for airspeed – traceable to the Nat'l Institute of Standards & Technology. COMMAND ELECTRONICS designed and built the Model 803 digital tester which checks and synchronizes against these Standard Calibration Tables EVERY 100 FT. This fact plus the PRECISION transducers incorporated in the COMMAND DIGITAL MODEL 803 make for extreme accuracy – almost absolute with the Tables. With these accurate parameters, the Model 803 can even be used as a standard for other similar equipment – since ACCURACY can be VERIFIED by any inspector within 5 minutes using a calibrated 5-1/2-digit voltmeter. This verification can be made at any moment in time.

To keep paying and sending back a digital tester for calibration/repair can cost as much as operating a Boeing B757/767 from St. Louis to the West Coast. Your certified avionic technicians are more simple to repair than an ADF or DME. Complete instructions are easy to follow in the manual and calibrating/repairing in your own shop gives you much more control over costs and time. In addition, since the Model 803 can be checked in 5 minutes at any inspection, you have the confidence of an inspection right on the spot.

We thought you might like to know this for your decision s in equipping your shop with the best. The COMMAND MODEL 803 is the only tester utilizing these Tables by this methods – which allows synchronization with the Tables to ultimately give you a Calibration Procedure allowing your technician to calibrate IN-HOUSE!

The Model 803 is equipped with an RS232 port which can adapt to most any computerized station you may already have in operation or be used with a remote handheld (also displaying the sample parameters).