Twin Engine Speed and Temperature Indicator

GEC Avionics Limited
ESTI S-?-B127
Part 270-24070
Ser ENG001

This was called ESTI (Engine Speed and Temperature Indicator) and was designed to be a reversionary instrument with a very low power usage. It was used where power failure meant only minimal instrumentation could be used (such as when the HUD or main screens were down). This instrument was designed by Powerplant Systems Division and was one of a new generation of instruments using Liquid Crystal displays. It was one of the first developments for LCD backlighting in PSD and one of the first flight certificated LCD instruments. The display is effectively one continuous series of elements and the display is updated every 32ms. It is capable of reading signals as analogue frequencies and converting them to digital values.

For Left and Right engines the Instrument provides twin analogue NH indicators (0-105% of high-pressure turbine's rated speed) and twin digital TBT readouts (for Turbine Blade Temperatures).