Reset of Elapsed Time and Chronometer Counter

TASK 31-21-00-860-801-A
Reset of Elapsed Time and Chronometer Counter

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.

ZONE: 210

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

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

B. 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)
Clock

3. Job Set-up
Subtask 31-21-00-861-052-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 31-21-00-865-056-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	CLOCK/NORM/SPLY	6FS	F11
121VU	CLOCK/STBY/SPLY	4FS	N02

4. Procedure
Subtask 31-21-00-860-052-A ** ON A/C NOT FOR ALL

A. Reset of Elapsed Time and Chronometer Counter

Clock ** ON A/C NOT FOR ALL

ACTION	RESULT
On panel 400VU, on the clock: 1.Set the GPS/INT/SET selector switch to INT. NOTE: If the numbers for the seconds are known, set the selector switch to INT only when they change from 59 to 00.	On the UTC display of the clock: The clock internal time is set and the counter for the time starts. The two right digits for the seconds are set to zero (00 comes into view) and start to increase.
2.Do a reset of the chronometer counter:	On the CHR display of the clock:
Push and release the RST pushbutton switch.	The display comes blank.
3.Do a reset of the elapsed time counter:	On the ET display of the clock:
Set and release the RUN/STP/RST selector switch to RST.	The display comes blank.

5. Close-up
Subtask 31-21-00-860-053-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).
(2) Make sure that the work area is clean and clear of tools and other items.

[Rev.10 from 2021] 2026.04.01 00:33:20 UTC