Installation of the Mechanic Call Horn

TASK 23-42-21-400-001-A
Installation of the Mechanic Call Horn

ZONE: 120
ZONE: 700
FIN: 15WC

1. Reason for the Job
Self explanatory
2. Job Set-up Information
A. Fixtures, Tools, Test and Support Equipment

REFERENCE	QTY	DESIGNATION
No specific	1	ACCESS PLATFORM 2M (6 FT) - ADJUSTABLE
No specific	AR	WARNING NOTICE(S)

B. Work Zones and Access Panels

ZONE/ACCESS	ZONE DESCRIPTION
120	AVIONICS COMPARTMENT
700	LANDING GEAR AND LANDING GEAR DOORS
713, 714

C. Referenced Information

REFERENCE	DESIGNATION
TASK 23-42-00-710-001-A	Operational Test of the Mechanic Call
TASK 32-22-00-010-001-A	Nose Gear Doors - Ground Doors Opening
TASK 32-22-00-410-001-A	Nose Gear Doors - Ground Doors Closing
ESPM 2043130
ESPM 2048250
ASM 234201
AWM 234202
Mechanic Call Horn

3. Job Set-up
Subtask 23-42-21-860-051-A

A. Aircraft Maintenance Configuration
(1) Make sure that you put a WARNING NOTICE(S) in the cockpit to tell persons not to operate the landing gear.
(2) Make sure that the main doors 713 and 714 of the nose landing gear well (Ref. AMM TASK 32-22-00-010-001) are open.
(3) Make sure that the ACCESS PLATFORM 2M (6 FT) - ADJUSTABLE is in position under the nose landing gear well.

Subtask 23-42-21-865-051-A

B. Make sure that this(these) circuit breaker(s) is(are) open, safetied and tagged:

PANEL	DESIGNATION	FIN	LOCATION
** ON A/C ALL
121VU	EIS/HORN/SPLY	2WC	P09

4. Procedure

CAUTION: DO NOT APPLY TOO MUCH PRESSURE ON THE MOBILE PART OF THE HORN. TOO MUCH PRESSURE WILL CAUSE DAMAGE TO THE HORN (WILL DECREASE THE CLEARANCE BETWEEN THE MOBILE AND FIXED PARTS).

Subtask 23-42-21-420-050-B

A. Installation of the Mechanic Call Horn
(1) Clean the component interfaces and the adjacent area.
(2) Do an inspection of the component interfaces and the adjacent area.
(3) Install the mechanic call horn (11) on the support (12).
(4) Put the three washers (9) and the screws (8) in position.
(5) Tighten the screws (8).
(6) Put the support (12) on the cover (2).
(7) Put the four washers (6) and the screws (5) in position.
(8) Tighten the screws (5).
(9) Use the applicable tool ASM 234201 AWM 234202 ESPM 2048250 ESPM 2043130 to connect the power supply wires (4).
(10) Slowly close the cover (2) of the box (3).
(11) Hold the cover (2) of the box (3) and tighten the three quick-release fasteners (1) by a quarter turn.

Subtask 23-42-21-865-052-A

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

PANEL	DESIGNATION	FIN	LOCATION
** ON A/C ALL
121VU	EIS/HORN/SPLY	2WC	P09

Subtask 23-42-21-710-051-A

C. Do the operational test of the mechanic call (Cockpit-to-Ground Crew Call only) (Ref. AMM TASK 23-42-00-710-001).

5. Close-up
Subtask 23-42-21-410-050-A

A. Close Access
(1) Make sure that the work area is clean and clear of tools and other items.
(2) Remove the access platform(s).
(3) Remove the WARNING NOTICE(S).
(4) Close the main doors 713 and 714 of the nose landing gear well (Ref. AMM TASK 32-22-00-410-001).

[Rev.10 from 2021] 2026.04.05 10:34:37 UTC