(7)
 Optical module This module includes a LCD matrix, backlighting (light box with three tubes) and the control electronics for this lighting.

 7. Operation
_________
 A. System Performance The parameter computation frequency is sufficient to respect the required performances and to avoid important gap between two consecutive displayed values. The elapsed time between the acquisition of air data and the display of the parameters is less than 200 ms.
 (1) Standby airspeed indicator function
 The ISIS indicator can operate from 0 to 600 kts without
 deterioration.

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 (2)
 Standby altimeter function The ISIS indicator can operate from -2500 to 55,000 ft and at 40,000 ft/mn speed variation without deterioration.

 (3)
 Standby horizon function The ISIS indicator can operate from -180 to +180 deg. in pitch and roll without deterioration.

 -gyrometers (3): the indicator can follow a 100 deg./s pitch or roll variation, a 10,000 deg./square second angular acceleration. The associated monitoring is triggered when angular speeds becomes higher than 100 deg./s.
 -accelerometers (2): the associated monitoring is triggered when the constant acceleration in x and/or y axis becomes greater than 2.5g. If this monitoring is triggered, the "WAIT ATT" message is displayed (Ref. Fig. 022) If the conditions become normal againand if the attitude performance remains adequate for 10 seconds, the "WAIT ATT" message disappears and is replaced by the horizon display. Otherwise, after 10 seconds or if the attitude performance is affected, the attitude function is considered as failed and the "ATT:RST" message is displayed in place of the "WAIT ATT" message (Ref. Fig. 023) Pressing the RST pushbutton switch more than 2 seconds in steady flight quickly resets the attitude information.
 B. Control and Indicating The face of the ISIS indicator includes the following controls:
 (1) BUGS pushbutton switch (Ref. Fig. 024) When the BUGS pushbutton switch is pushed, the BUGS page is shown. This page is used to program characteristic speeds and altitudes displayed on speed and altitude scales respectively. The BUGS page has two columns positioned vertically: an SPD column made of four boxes and an ALT column made of two boxes.
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 ISIS INDICATOR - WAIT ATT Flag
 Figure 022

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 ISIS INDICATOR - ATT RESET Flag
 Figure 023

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 ISIS Indicator - Bugs Selection Display
 Figure 024

R 1EFF : 106-149, 213-213, 221-299, 301-399, 1 34-22-00Page 35 1401-499, 1Config-2 Aug 01/05 1 1 1CES 1 Initially, the first box of the SPD column (left top) is flashing. The corresponding speed value has to be selected using the BARO selector knob (cyan SET/SELECT indication followed by an arrow in the right bottom part of the display). This value cannot be less than 30 kts and can only be selected or changed when "OFF" function is deselected (true also with altitude bugs). When the correct value is displayed, access to the next box (below) is made by pushing the "-" pushbutton switch. This box is then active and flashes. After the fourth box of the SPD column, access to the last box of the ALT column (right top) is made by using the BARO selector knob. The altitude values selected cannot be negative. The "-" pushbutton switch is also used to select the last ALT box and then the first SPD box again. The "+" pushbutton switch is used to return to the previous box. The operational page is displayed again and the entered values are memorized by pushing the BUGS pushbutton switch or after 15 s without pilot action. These values are memorized until new values are entered, even in case of ISIS indicator power supply cutoff. If one memorized bug has not to be displayed on speed or altitude scale, it is possible to hide it by pushing the BARO selector knob. The OFF indication is shown close to the selected box and the value is still displayed. By pushing the BARO selector knob again, the displayed and memorized bug is active. Initially, speed bugs are set to 30 and altitude bugs are set to 0. All the bugs can be hidden using the OFF function.

 (2)
 RST pushbutton switch (Ref. Fig. 025) The RST (reset) pushbutton switch located in the left bottom part of the indicator enables to reset the attitude indication to the true value during stabilized flight (without pitch and roll angles and with stabilized speed). During the reset, a yellow ATT 10s message is shown in the center of the display area, in place of the horizon line. After a 10-second delay, the operational page is automatically displayed.
　
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