ISIS Inspection for Legibility

TASK 34-22-25-200-001-A
ISIS Inspection for Legibility

ZONE: 211

1. Reason for the Job
Self explanatory
2. Job Set-up Information
A. Work Zones and Access Panels

ZONE/ACCESS	ZONE DESCRIPTION
211	COCKPIT

B. Referenced Information

REFERENCE	DESIGNATION
TASK 12-21-12-100-001-A	Cleaning of the Cockpit Display-Units
TASK 24-41-00-861-002-A	Energize the Aircraft Electrical Circuits from the External Power
TASK 24-41-00-861-002-A-01	Energize the Aircraft Electrical Circuits from the APU
TASK 24-41-00-861-002-A-02	Energize the Aircraft Electrical Circuits from Engine 1(2)
TASK 24-41-00-862-002-A	De-energize the Aircraft Electrical Circuits Supplied from the External Power
TASK 24-41-00-862-002-A-01	De-energize the Aircraft Electrical Circuits Supplied from the APU
TASK 24-41-00-862-002-A-02	De-energize the Aircraft Electrical Circuits Supplied from the Engine 1(2)
TASK 34-22-25-000-001-A	Removal of the Integrated Standby Instrument System (ISIS) Indicator
TASK 34-22-25-400-001-A	Installation of the Integrated Standby Instrument System (ISIS) Indicator

3. Job Set-up
Subtask 34-22-25-860-066-A ** ON A/C NOT FOR ALL

A. Aircraft Maintenance Configuration
(1) Energize the aircraft electrical circuits
(Ref. AMM TASK 24-41-00-861-002)
(2) Clean the ISIS screen (Ref. AMM TASK 12-21-12-100-001)

Subtask 34-22-25-865-067-A ** ON A/C NOT FOR ALL

B. Make sure that this(these) circuit breaker(s) is(are) closed:

PANEL	DESIGNATION	FIN	LOCATION
** ON A/C NOT FOR ALL
49VU	NAV/STBY/INST	5FN	F12

4. Procedure
Subtask 34-22-25-710-051-A ** ON A/C NOT FOR ALL

A. On the ISIS indicator:

Push the (+) pushbutton switch to maximum brightness.

Subtask 34-22-25-740-053-A ** ON A/C NOT FOR ALL

B. On the ISIS indicator:

ACTION	RESULT
1.On the ISIS indicator: Push the BUGS and LS pushbutton switches at the same time and for more than two seconds.	On the ISIS indicator: The "TESTS and OTHER DATA" page comes into view.
Push the (+) pushbutton switch	The "FUNCTIONAL and DISPLAY TESTS" page comes into view.
Push the (-) pushbutton switch	The screen becomes black.

Subtask 34-22-25-280-050-A ** ON A/C NOT FOR ALL

C. From a distance of 0,40m (15,74inches), do a visual check of the black screen for:

A white line or a line in color,
A white column or a column in color,
Pixels that are failed-on.

NOTE: A failed-on pixel is a pixel which is always fully or not fully on (white or in color).
The black screen makes it possible to see the failed-on pixels.

(1) Count and record the pixels that are defective:

Number of failed-on pixels on the screen
Number of two adjacent failed-on pixels on the screen
Number of sets of two adjacent failed-on pixels on the screen
White line or line in color, white column or column in color.

Subtask 34-22-25-740-054-A ** ON A/C NOT FOR ALL

D. On the ISIS indicator, push the (-) pushbutton switch. The screen becomes white.

Subtask 34-22-25-280-051-A ** ON A/C NOT FOR ALL

E. From a distance of 0,40m (15,74inches), do a visual check of the white screen for:

A black line or a line in color
A black column or a column in color
Pixels that are failed-off.

NOTE: A failed-off pixel is a pixel which is always fully or not fully off (black or in color).
The white screen makes it possible to see the failed-off pixels.

(1) Count and record the pixels that are defective:

Number of failed-off pixels on the screen
Number of two adjacent failed-off pixels on the screen
Number of sets of two adjacent failed-off pixels on the screen
Black line or line in color, black column or column in color.

Subtask 34-22-25-710-052-A ** ON A/C NOT FOR ALL

F. For each screen, if the defective pixels recorded do not obey these conditions:

You must not have more than two adjacent failed-on or failed-off pixels
You must not have more than 5 sets of two adjacent failed-on or failed-off pixels
You must not have a white or black line or column, or a line or column in color
The total of failed-on and failed-off pixels must not be more than 30 pixels,
replace the ISIS indicator (Ref. AMM TASK 34-22-25-000-001) and (Ref. AMM TASK 34-22-25-400-001).
Then, on the ISIS indicator, push the RST pushbutton switch three times to come back to the operational page.
Push the (-) pushbutton switch to come back to a normal brightness.

5. Close-up
Subtask 34-22-25-410-053-A ** ON A/C NOT FOR ALL

A. Put the aircraft back to its initial configuration.
(1) De-energize the aircraft electrical circuits
(Ref. AMM TASK 24-41-00-862-002)
Make sure that the work area is clean and clear of tools and other items.

[Rev.10 from 2021] 2026.04.02 06:23:15 UTC