Jeppesen Sanderson avstar by Texas Instruments

Date of introduction:  1986 Display technology:  LCD
New price:   Display size:  8
Size:  5.3" x 2.8" x 0.45"
 135 x 70 x 11 mm3
Weight:  2.3 ounces, 64 grams Serial No:  0303409
Batteries:  2*LR44 Date of manufacture:  mth 07 year 1989
AC-Adapter:   Origin of manufacture:  Taiwan (C)
Precision:  11 Integrated circuits:  TP0328
Memories:  1    
Program steps:   Courtesy of:  Joerg Woerner

Avstar_C0789_Back.jpg (62261 Byte)This Flight computer developed by the Aviation specialist Jeppesen Sanderson and calculator manufacturer Texas Instruments is based on the avstar slimline model introduced in the year 1980. We assume that the original avstar suffered from the same keyboard problems known from other slimline models like the TI-35. Four years later a more reliable keyboard was available from the TI-35-II and as a consequence we got this wonderful avstar. 

Avstar_C0789_PCB.jpg (122147 Byte)Avstar_C0789_PCB1.jpg (97126 Byte)Dismantling an avstar Flight computer manufactured in July 1989 by Compal Electronics in Taiwan reveals an unusual construction with a well known TP0328 single-chip calculator circuit.

A more sophisticated Flight computer sold as prostar by Jeppesen Sanderson used the slanted housing known from the TI-55-II.
Later Flight computers sold by Jeppesen Sanderson like the Techstar based on a non-TI design.

Don't miss the rare APOTHECALC computer using similar technology for a different application.

The colorful keyboard of this Flight computer makes it easy to understand the functions.

Alt/AS: Calibrated, True Airspeed, Pressure, Density Altitude
WIND: Wind Speed, Direction, Course and Heading 
TSD: Time-Speed-Distance, Distance and fuel consumption
CMP: Computes in the above modes the different values
CNV: Convert between US and SI-units
T: Time calculations

Altidude/Airspeed Mode:

PA - stores a value in the pressure altidude register.
DA - computes the density altitude.
TC - stores a value in the true temperature register.
IC - stores a value in the indicated temperature register.
TAS - computes the true airspeed
CAS - stores a value in the calibrated airspeed register

WIND Mode:

WDr - stores a value in the wind direction register.
WSp - stores a value in the wind speed register.
TAS - stores a value in the true airspeed register. Could use a calculated value from Altidude/Airspeed mode, too.
Crs - stores a value in the course register.
Hdg - stores a value in the heading register.
G/ff - stores a value in the groundspeed register

Time-Speed-Distance Mode:

TIME - stores a value in the time register.
Ds/F - stores a value in the distance or fuel quantity register.
G/ff - stores a value in the groundspeed or fuel per hour register.

Sample Problem - Finding Time:

This example demonstrates you the usage of the Flight computer for a simple calculation:

Your groundspeed is 120 knots, the distance 140 nautical miles. How long is the time enroute ?

TSD  140 Ds/F  120 G/ff  CMP  TIME displays the result 1-10-00 (one hour and ten minutes)

horizontal rule

If you have additions to the above article please email:

Joerg Woerner, December 5, 2001. No reprints without written permission.