Removal of the Standby Horizon Indicator

TASK 34-22-24-000-001-A
Removal of the Standby Horizon Indicator

CAUTION: DO NOT REMOVE THE INDICATOR IMMEDIATELY AFTER DE-ENERGIZATION OF THE INDICATOR. THERE MUST BE 20 MINUTES OR MORE BETWEEN ITS DE-ENERGIZATION AND THE START OF THE REMOVAL PROCEDURE. BE CAREFUL WITH INDICATOR DURING THE REMOVAL/INSTALLATION PROCEDURES, THE STANDBY HORIZON INDICATOR IS A FRAGILE INSTRUMENT.

NOTE: After long low-rate turns (less than 10 degree bank) the standby horizon indicator does not give accurate bank indications immediately. The specification of the standby horizon indicator accepts this type of operation. Thus, it is not necessary to replace the indicator.

ZONE: 211
FIN: 7FN ** ON A/C NOT FOR ALL

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

REFERENCE	QTY	DESIGNATION
No specific	AR	CAP - BLANKING
No specific	AR	SAFETY CLIP - CIRCUIT BREAKER
No specific	AR	WEDGE - LOCKING
F1402369	1	EXTRACTING TOOL

B. Work Zones and Access Panels

ZONE/ACCESS	ZONE DESCRIPTION
211	COCKPIT

C. Referenced Information

REFERENCE	DESIGNATION
Standby Horizon Indicator

3. Job Set-up
Subtask 34-22-24-865-050-A ** ON A/C NOT FOR ALL

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

PANEL	DESIGNATION	FIN	LOCATION
** ON A/C NOT FOR ALL
49VU	NAV/STBY/HORIZON	5FN	F12
122VU	LIGHTING/INSTL LT/MAIN INST/PNL AND/PED	4LF	Y04

Subtask 34-22-24-010-050-A ** ON A/C NOT FOR ALL

B. Remove the thermoformed cover from the center instrument panel.

4. Procedure
Subtask 34-22-24-020-050-A ** ON A/C NOT FOR ALL

A. Removal of the Standby Horizon Indicator (7FN)

CAUTION: IF YOU MOVE THE STANDBY HORIZON INDICATOR WHEN IT IS REMOVED, MAKE SURE THAT YOU FIRST BLOCK THE GYROSCOPE ASSEMBLY WITH THE LOCKING WEDGE (SUPPLIED WITH THE INSTRUMENT).

(1) To cage the standby horizon indicator: pull knob (1) and insert the WEDGE - LOCKING
(2) Loosen the two screws (2). Do not remove them.
(3) Push the screws (2) to release the standby horizon indicator (3) from the clamp.
(4) Disengage the standby horizon indicator (3) from its housing with F1402369 EXTRACTING TOOL.
(5) Disconnect the electrical connector (5).
(6) Remove the standby horizon indicator (3).
(7) Put CAP - BLANKING on the disconnected electrical connectors (4) and (5).

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