Installation of the Air Data Tubes

TASK 20-23-11-911-004-A
Installation of the Air Data Tubes

1. Reason for the Job
To install flexible and rigid air data tubes, these tubes are connected to the pitot and static system.
2. Job Set-up Information
A. Fixtures, Tools, Test and Support Equipment

REFERENCE	QTY	DESIGNATION
No specific	1	WARNING NOTICE(S)

B. Referenced Information

REFERENCE	DESIGNATION
TASK 20-21-11-911-001-A	Tightening Torques for Standard Threaded Fasteners
TASK 20-21-12-911-001-A	Tightening Torques for Pipe Unions (not for OXYGEN Unions)
TASK 20-23-22-910-001-A	Marking of the Unions after Application of Standard or Specific Tightening Torque
TASK 20-28-00-912-802-A	Electrical Bonding - General Maintenance Procedure
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 34-13-00-790-002-A	Leak Test of the Principal Static and Total Air Data System
TASK 34-21-00-790-001-A	Low-Range Leak Test of the Standby Pneumatic Circuits
TASK 34-22-25-790-001-A	Low range Leak Test of the Standby Pneumatic circuits
AIPC 34-11-01-
Illustration of the Quick-diconnect coupling

3. Job Set-up
Subtask 20-23-11-860-067-A

A. Aircraft Maintenance Configuration
(1) Energize the aircraft electrical circuits
(Ref. AMM TASK 24-41-00-861-002).

Subtask 20-23-11-941-056-A

B. Safety Precautions
(1) Put a WARNING NOTICE(S) in position to tell person not to operate the systems in the area of installation of the air data tubes.

Subtask 20-23-11-917-094-A

C. General

CAUTION: YOU MUST BE CAREFUL WITH THE TUBES TO PREVENT IMPACTS, DISTORTIONS AND SCRATCHES.

CAUTION: WHEN DUST CAPS ARE USED FOR THE PROTECTION OF OPEN LINES AGAINST CONTAMINATION, ALWAYS BE SURE TO INSTALL THE CAPS AROUND THE TUBE ENDS AND NOT IN THE TUBE ENDS. THERE CAN BE BLOCKAGE OF THE FLOW THROUGH THE TUBES IF THESE TUBES ARE INSTALLED ACCIDENTALLY WITH DUST CAPS IN THE TUBE ENDS.

(1) Make sure that all the equipment items that must be connected are in the correct position. You must do this so that it will not be necessary to remove the tubes subsequently.
(2) Make sure that the tube installation area is clean and in the correct condition to prevent contamination of the air data tubes when you remove the caps.
(3) Make sure that the parts you assemble are clean and have no contamination.

4. Procedure
Subtask 20-23-11-420-056-A

A. Installation of the Air Data Tubes
(1) Make sure that the tube end fittings are not damaged.
(a) Examine the threads of the fittings.
(b) Examine the sealing surfaces.
(c) Examine the tube for scratches, nicks, deformations, etc.

NOTE: Reject parts that show signs of damage.

(2) Install the clamp blocks on the tube. If necessary, replace the damaged clamp blocks.

NOTE: Refer to AIPC 34-11-01- for correct clamp block P/N and location on tube.

(3) Put the tube in position and make sure that:

The tube you install is not too short or too long
You can put the tube in position without too much force on the clamp blocks.

(4) Remove the caps.

CAUTION: TO PREVENT CONTAMINATION OF THE SYSTEM, DO NOT APPLY LUBRICANT TO THE TUBES AND/OR FITTINGS.

(5) Align the tube and the fitting and engage the tube end.

CAUTION: MAKE SURE YOU DO NOT TWIST THE TUBES WHEN YOU INSTALL THEM. IF YOU TWIST THE TUBES, YOU CAN PUT A LOAD ON THEM WHICH CAN DAMAGE THEM.

CAUTION: DO NOT BEND THE TUBE WHEN YOU INSTALL IT. IF THE TUBE IS BENT IT CAN BE DAMAGED.

(6) Tighten the attachment bolts of the clamp blocks with your hand only sufficiently to prevent that the tubes fall.
(7) Tighten the connection with your hand.
(8) Make sure that the tube routing does not make a low point.

CAUTION: DO NOT APPLY MORE THAN THE SPECIFIED TORQUE. IF YOU DO, YOU CAN CAUSE DAMAGE TO THE TUBES.

(9) TORQUE the connection to the applicable value (Ref. AMM TASK 20-21-12-911-001).
(10) Make a mark on the unions after you apply the standard tightening torque values (Ref. AMM TASK 20-23-22-910-001).
(11) TORQUE the clamp blocks to the applicable values (Ref. AMM TASK 20-21-11-911-001).
(12) Make sure that the installed tube does not touch the fixed structure, parts that move and other parts.

NOTE: To measure the clearance between a tube and a part that can move, you must measure the distance in the condition where the movement decreases the distance to its smallest value.

(13) Do the electrical bonding of the pipes (Ref. AMM TASK 20-28-00-912-802).

Subtask 20-23-11-420-057-A

B. Quick-Disconnect Connection (If necessary)

Illustration of the Quick-diconnect coupling

(1) Connect the quick-disconnect coupling to the related connector.
(2) Make sure that you can see the blue ring on the quick-disconnect coupling.
(3) Pull the quick-disconnect coupling to be sure that it is correctly attached.

Subtask 20-23-11-710-051-A ** ON A/C NOT FOR ALL

C. Test
(1) Do a leak test of the air data system.

If you disconnected the main system: (Ref. AMM TASK 34-13-00-790-002)
If you disconnected the standby system: (Ref. AMM TASK 34-21-00-790-001)

Subtask 20-23-11-710-051-B ** ON A/C NOT FOR ALL

C. Test
(1) Do a leak test of the air data system.

If you disconnected the main system: (Ref. AMM TASK 34-13-00-790-002)
If you disconnected the standby system: (Ref. AMM TASK 34-22-25-790-001)

5. Close-up
Subtask 20-23-11-410-054-A

A. Close Access
(1) Make sure that the work area is clean and clear of tools and other items.
(2) Remove the WARNING NOTICE(S).

Subtask 20-23-11-862-051-A

B. De-energize the aircraft electrical circuits (Ref. AMM TASK 24-41-00-862-002).

[Rev.10 from 2021] 2026.03.31 22:59:21 UTC