T.VASIS was introduced in Australia in 1972. It is not used anywhere else in the world. The rest of the world use PAPI and Australia are slowly following suit. The benefits of converting from T.VASIS to PAPI are as follows -:

Real cost recovery inside 3 years. Power consumption reduced by at least 60%. Maintenance labour reduced by at least 85%. Purchasing of spare parts reduced by at least 90%.

Levelling a T.VASIS system takes 2 people a day to acheive. Levelling a PAPI system takes 1 person an hour!

A T.VASIS system consists of 10 light boxes either side of the runway. TVASIS uses 20 light boxes! PAPI uses 8.

Each light box contains FOUR x 100 Watt lamps for use by day and TWO x 35 Watt lamps for use at night. The number of lamps in the system is therefore 80 x 100 Watt lamps and 40 x 35 Watt lamps, for a total of 120 lamps. TVASIS uses 120 lamps! PAPI only requires 16.

Each light box uses TWO x 200 Watt series isolation transformers and TWO x 30 Watt series isolation transformers.The number of transformers in the system is therefore 40 x 200 Watt and 40 x 30 Watt. For a total of 80 X transformers. TVASIS uses 80 transformers! PAPI only requires 16.

During daylight hours the total electrical load drawn by a TVASIS system is 8,000 Watts. TVASIS consumes 8kW of power! PAPI uses only 3.2 kW.

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