Low-Range Leak Test of the Standby Pneumatic Circuits

TASK 34-21-00-790-001-A
Low-Range Leak Test of the Standby Pneumatic Circuits

WARNING: MAKE SURE THAT ALL THE CIRCUITS IN MAINTENANCE ARE ISOLATED BEFORE YOU SUPPLY ELECTRICAL POWER TO THE AIRCRAFT. UNWANTED ELECTRICAL POWER CAN BE DANGEROUS.

WARNING: MAKE SURE THAT THE SAFETY DEVICES AND THE WARNING NOTICES ARE IN POSITION BEFORE YOU START A TASK ON OR NEAR:

THE FLIGHT CONTROLS
THE FLIGHT CONTROL SURFACES
THE LANDING GEAR AND RELATED DOORS
COMPONENTS THAT MOVE.

MOVEMENT OF COMPONENTS CAN KILL OR CAUSE INJURY TO PERSONS AND/OR DAMAGE TO EQUIPMENT.

WARNING: MAKE SURE THAT THE TRAVEL RANGES OF THE FLIGHT CONTROLS SURFACES ARE CLEAR. MOVEMENT OF FLIGHT CONTROLS CAN CAUSE INJURY TO PERSONS AND/OR DAMAGE TO EQUIPMENT.

CAUTION: TO PREVENT DAMAGE TO INSTRUMENTS, OBEY THESE PRECAUTIONS WHEN YOU DO THE TEST:

THE PRESSURES SET MUST NOT BE MORE THAN 1050 hPa (31 in Hg) OR LESS THAN 115 hPa (3.39 in Hg)
CHANGES IN STATIC AND TOTAL PRESSURES MUST NOT BE MORE THAN 6000 FEET/MINUTE
DO NOT SUDDENLY OPEN LINES TO AMBIENT AIR WHILE THE PRESSURE GENERATOR IS CONNECTED.

CAUTION: THE TOTAL PRESSURE IN THE PITOT SYSTEM MUST NEVER BE LESS THAN THE STATIC PRESSURE. THE DIFFERENCE BETWEEN THE PITOT AND THE STATIC PRESSURE CIRCUITS MUST NEVER BE MORE THAN 368 hPa (10.86 in Hg).

CAUTION: DURING THE LEAK TEST, SLOWLY BALANCE THE PRESSURE IN THE STANDBY STATIC AND PITOT CIRCUITS ON THE GROUND PRESSURE GENERATOR. IF YOU DO NOT DO THIS, DAMAGE TO THE AIR SPEED INDICATOR WILL OCCUR.

ZONE: 120
ZONE: 210

1. Reason for the Job
Refer to the MPD TASK: 342100-01
LOW RANGE LEAK TEST OF STANDBY PNEUMATIC CIRCUITS
- To make sure that there are no leaks in the standby static and pitot circuits.
2. Job Set-up Information
A. Fixtures, Tools, Test and Support Equipment

REFERENCE	QTY	DESIGNATION
No specific	AR	SAFETY CLIP - CIRCUIT BREAKER
ALT34100001	1	PITOT AND STATIC TEST SET

B. Work Zones and Access Panels

ZONE/ACCESS	ZONE DESCRIPTION
120	AVIONICS COMPARTMENT
210	CKPT,FWD COMPT BHD TO FLT COMPT BULKHEAD

C. Referenced Information

REFERENCE	DESIGNATION
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 27-50-00-866-009-A	Retraction of the Flaps on the Ground
TASK 27-50-00-866-009-A-01	Retraction of the Flaps/Slats on the Ground
TASK 31-60-00-860-001-A	EIS Start Procedure
TASK 31-60-00-860-002-A	EIS Stop Procedure
TASK 34-11-15-200-001-A	Inspection/Check of the Pitot Probe
Installation of the Pitot and the Static Test Set
Setting of the AOA Sensor Vane to the High Stop Position

3. Job Set-up
Subtask 34-21-00-860-056-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).

Subtask 34-21-00-865-050-A ** ON A/C NOT FOR ALL

WARNING: OPEN CIRCUIT BREAKER 7XE. THIS WILL PREVENT A POSSIBLE DEPLOYMENT OF THE RAT IF THE MAIN AC BUSBARS 1XP AND 2XP BECOME ISOLATED.

B. Open, safety and tag this(these) circuit breaker(s):

PANEL	DESIGNATION	FIN	LOCATION
** ON A/C NOT FOR ALL
49VU	ANTI ICE/PROBES/AOA/1	4DA1	D04
49VU	ANTI ICE/PROBES/PITOT/1	3DA1	D02
105VU	ELEC/CSM/G /EV AUTO/SPLY	7XE	C01
122VU	ANTI ICE/PROBES/2/TAT	1DA2	Y15
122VU	ANTI ICE/PROBES/2/PITOT	3DA2	Y14
122VU	ANTI ICE/PROBES/2/AOA	4DA2	Y13
122VU	ANTI ICE/PROBES/2/STATIC	5DA2	Y11
122VU	ANTI ICE/PROBES/3/PITOT	3DA3	Z16
122VU	ANTI ICE/PROBES/3/AOA	4DA3	Z15
122VU	ANTI ICE/PROBES/3/STATIC	5DA3	Z14
122VU	ANTI ICE/PROBES/1/STATIC	5DA1	Z13
122VU	ANTI ICE/PROBES/1/TAT	1DA1	Z12

Subtask 34-21-00-865-052-A ** ON A/C NOT FOR ALL

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

PANEL	DESIGNATION	FIN	LOCATION
** ON A/C NOT FOR ALL
49VU	NAV/STBY/ALTM	16FN	F14

Subtask 34-21-00-420-050-D ** ON A/C NOT FOR ALL

D. Connection of the Ground Pressure Generator

Installation of the Pitot and the Static Test Set ** ON A/C NOT FOR ALL

(1) Remove the slip on covers from the static probe and the pitot probe of the standby system.
(2) Connect the ALT34100001 PITOT AND STATIC TEST SET to one standby static-probe with the STATIC PORT ADAPTER from the ADAPTER STATIC PROBE.
(3) Connect the ALT34100001 PITOT AND STATIC TEST SET to the standby pitot probe with the ADAPTER PITOT PROBE.

NOTE: The ADAPTER PITOT PROBE is on the drain hole. Thus it is not necessary to seal the drain hole of the pitot probe.

(4) Seal the opposite standby static-probe with a piece of plastic and with the ADAPTER STATIC COVER from the ADAPTER STATIC PROBE.
(5) Turn the vane of the Angle Of Attack (AOA) sensor 3FP3 to the high stop position.

Setting of the AOA Sensor Vane to the High Stop Position ** ON A/C NOT FOR ALL

(a) Maintain the vane in position with colored adhesive tape.

Subtask 34-21-00-860-058-A ** ON A/C NOT FOR ALL

E. Aircraft Maintenance Configuration
(1) Do the EIS start procedure (PFD only) (Ref. AMM TASK 31-60-00-860-001).
(2) Make sure that the flaps are in the fully retracted position (Ref. AMM TASK 27-50-00-866-009).
(3) On the ADIRS CDU, set the OFF/NAV/ATT selector switches to NAV.
(4) Start the ground pressure generator.

4. Procedure
Subtask 34-21-00-790-050-K ** ON A/C NOT FOR ALL

A. Leak Test

NOTE: The input parameters for the ground test (speed and altitude) and the values shown on the cockpit displays are different because of the sum of the tolerances of the air data circuit (ground test unit, Air Data Modules (ADM), Air Data/Inertial Reference Units (ADIRU)).

(1) For the aircraft with the Reduced Vertical Separation Minimum (RVSM) function:

The Primary Flight Display (PFD) altitude value given in the test is not corrected with the trim adjustment value.
Thus, it is necessary to correct the PFD altitude value with the trim adjustment value given on a placard installed on the rack of ADIRU3.

ACTION	RESULT
1.On the ground pressure generator do the pre-test that is given below for a static pressure of 691 hPa and an impact pressure of 59.3 hPa (or a total pressure of 750.3 hPa). This pre-test is less accurate than the leak test.
2.On SWITCHING panel 8VU, set the AIR DATA selector switch to the CAPT ON 3 (or the F/O ON 3) position.	On the CAPT (or F/O) PFD, the indications from ADIRU3 are shown.
Make sure that: The CAPT (or F/O) PFD shows 10 177 ft +/- 30 ft and 188 kts +/- 3kts. The standby altimeter and the standby airspeed indicator show 10 216 ft +/- 83 ft, 3113.83 m +/- 25 m and 189 kts +/- 5 kts.	After 5 minutes: The change of altitude must not be more than 370 ft or 112.8 m. The change of speed must not be more than 10 Kts.
3.On the standby altimeter and on the metric altimeter, set a barometric pressure of 1013 hPa.	On the CAPT (or F/O) PFD, the indications from ADIRU3 are shown.
4.On the ground pressure generator, slowly balance the pressure in the standby static and pitot circuits: Set a static pressure of 462.4 hPa or 13.65 in.Hg. (or 20 000 ft). Set an impact pressure of 179.1 hPa or 5.28 in.Hg. (or a total pressure of 641.5 hPa or 18.94 in.Hg.) (or 320 kts).	Make sure that: - The CAPT (or F/O) PFD shows 20 918 ft +/- 30 ft and 335 kts +/- 3 kts. - The standby altimeters and the standby airspeed indicator show 20 166 ft +/- 135 ft, 6146.59 m +/- 41 m and 323 kts +/- 5 kts.
5.Close the electrovalves to isolate the static and pitot circuits of the aircraft from the ground pressure generator.	After 5 minutes: Make sure that the change of altitude is not more than 500 ft or 152.4 m. After 10 minutes: Make sure that the change of speed is not more than 20 Kts.
6.On the ground pressure generator: Open the electrovalves and slowly balance the pressure in the standby static and pitot circuits. Set a static pressure of 500 hPa for one minute. Set a static pressure of 575 hPa for one minute. Set a static pressure of 650 hPa and a total pressure of 700 hPa for one minute. Set a static pressure of 725 hPa and a total pressure of 775 hPa for one minute. Set a static pressure of 800 hPa and a total pressure of 850 hPa for one minute. Set a static pressure of 900 hPa and a total pressure of 950 hPa for one minute. Open the electrovalves to get the atmospheric pressure.
7.Stop the ground pressure generator.

5. Close-up
Subtask 34-21-00-020-050-C ** ON A/C NOT FOR ALL

A. Remove the ground pressure generator
(1) Disconnect the ALT34100001 PITOT AND STATIC TEST SET.
(2) Remove the adaptors from the standby static probe and the standby pitot probe.
(3) Remove the cover from the opposite standby static probe.
(4) Remove the piece of plastic from the opposite standby static probe.
(5) Remove adhesive tape from the vane of the AOA sensor 3FP3.

Subtask 34-21-00-865-051-A ** ON A/C NOT FOR ALL

B. Remove the safety clip(s) and the tag(s) and close this(these) circuit breaker(s):

PANEL	DESIGNATION	FIN	LOCATION
** ON A/C NOT FOR ALL
49VU	ANTI ICE/PROBES/AOA/1	4DA1	D04
49VU	ANTI ICE/PROBES/PITOT/1	3DA1	D02
105VU	ELEC/CSM/G /EV AUTO/SPLY	7XE	C01
122VU	ANTI ICE/PROBES/2/TAT	1DA2	Y15
122VU	ANTI ICE/PROBES/2/PITOT	3DA2	Y14
122VU	ANTI ICE/PROBES/2/AOA	4DA2	Y13
122VU	ANTI ICE/PROBES/2/STATIC	5DA2	Y11
122VU	ANTI ICE/PROBES/3/PITOT	3DA3	Z16
122VU	ANTI ICE/PROBES/3/AOA	4DA3	Z15
122VU	ANTI ICE/PROBES/3/STATIC	5DA3	Z14
122VU	ANTI ICE/PROBES/1/STATIC	5DA1	Z13
122VU	ANTI ICE/PROBES/1/TAT	1DA1	Z12

Subtask 34-21-00-860-057-A ** ON A/C NOT FOR ALL

C. Put the aircraft back to its initial configuration.
(1) On SWITCHING panel 8VU, set the AIR DATA selector switch to NORM position.
(2) Do the Electronic Instrument System (EIS) stop procedure (PFD only) (Ref. AMM TASK 31-60-00-860-002).
(3) On the ADIRS CDU, set the OFF/NAV/ATT selector switches to OFF.
(4) Do the reset of each ELAC:
(a) FOR [2CE1] (ELAC-1)
1 Open, then close circuit breakers 15CE1 and 16CE1.
(b) FOR [2CE2] (ELAC-2)
1 Open, then close circuit breakers 15CE2 and 16CE2.
(5) De-energize the aircraft electrical circuits
(Ref. AMM TASK 24-41-00-862-002).
(6) Make sure that the work area is clean and clear of tools and other items.
(7) Make sure that the drain holes on the pitot probes are not blocked by unwanted materials (Ref. AMM TASK 34-11-15-200-001).
(8) Install the slip on covers on the standby static probe and the standby pitot probe.

[Rev.10 from 2021] 2026.04.01 00:59:35 UTC