Inspection/Check of the Left Ignition Lead [CFMB]

TASK 74-21-20-200-002-A
Inspection/Check of the Left Ignition Lead

WARNING: BEFORE YOU START WORK ON THE IGNITION SYSTEM, MAKE SURE THAT THE IGNITION EXCITERS ARE DE-ENERGIZED FOR A MINIMUM OF FIVE MINUTES. ALSO DO NOT TOUCH THE ELECTRICAL CONTACTS. THE IGNITION SYSTEM VOLTAGE IS VERY HIGH, AND THE IGNITION EXCITERS CAN HAVE AN ELECTRICAL CHARGE EVEN WHEN NOT ENERGIZED. IF YOU DO NOT OBEY THESE PRECAUTIONS, INJURY CAN OCCUR.

CAUTION: BE CAREFUL WITH THE IGNITION LEAD TO PREVENT DAMAGE TO THE CONDUIT AND THE INTERNAL WIRES.

FIN: 1000EM1 ** ON A/C NOT FOR ALL
FIN: 1000EM2 ** 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	SAFETY CLIP - CIRCUIT BREAKER
No specific	AR	WARNING NOTICE(S)

B. Consumable Materials

REFERENCE	DESIGNATION
(Material No.CP1011)	1,1,1 trichlorethane

C. Work Zones and Access Panels

ZONE/ACCESS	ZONE DESCRIPTION
FOR [1000EM1] (ENGINE-1)
437AL, 438AR, 451AL, 452AR
FOR [1000EM2] (ENGINE-2)
447AL, 448AR, 461AL, 462AR

D. Referenced Information

REFERENCE	DESIGNATION
TASK 71-13-00-010-040-B	Opening of the Fan Cowl Doors
TASK 71-13-00-410-040-B	Closing of the Fan Cowl Doors
TASK 74-21-20-000-002-A	Removal of the Left Ignition Lead
TASK 74-21-20-300-004-A	Repair of the Burned or Pitted Igniter Contact
TASK 74-21-20-300-005-A	Replacement of the Ceramic Insulator Sleeve
TASK 74-21-20-300-006-A	Repair of the Chafe Guard
TASK 74-21-20-400-002-A	Installation of the Left Ignition Lead
TASK 78-30-00-081-041-B	Make the Thrust Reverser Serviceable after Maintenance
TASK 78-30-00-481-041-B	Make the Thrust Reverser Unserviceable for Maintenance
TASK 78-36-00-010-040-B	Opening of the Thrust Reverser Doors
TASK 78-36-00-410-040-B	Closing of the Thrust Reverser Doors
Inspection of the Left Ignition Lead

3. Job Set-up
Subtask 74-21-20-941-053-A ** ON A/C NOT FOR ALL

A. Safety Precautions
(1) On the center pedestal, on the ENG panel 115VU:
(a) Put a WARNING NOTICE(S) to tell persons not to start the engine.
(2) Make sure that the engine 1(2) shutdown occurred not less than 5 minutes before you do this procedure.
(3) On the overhead maintenance panel 50VU:
(a) Make sure that the ON legend of the ENG/FADEC GND PWR/1(2) pushbutton switch is off.
(b) Put a WARNING NOTICE(S) to tell persons not to energize the FADEC 1(2).

Subtask 74-21-20-865-058-A ** ON A/C NOT FOR ALL

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

PANEL	DESIGNATION	FIN	LOCATION
** ON A/C NOT FOR ALL
49VU	ENGINE/1 AND 2/IGN/SYS A	1JH	A03
FOR FIN: 1000EM1 (ENGINE1)
121VU	ENGINE/IGN/ENG1/SYS B	3JH1	P41
121VU	ENGINE/IGN/ENG1/SYS A BAT	2JH1	P39
FOR FIN: 1000EM2 (ENGINE2)
121VU	ENGINE/IGN/ENG2/SYS B	3JH2	P42
121VU	ENGINE/IGN/ENG2/SYS A BAT	2JH2	P40

Subtask 74-21-20-010-056-A ** ON A/C NOT FOR ALL

C. Open the fan cowl doors: (Ref. AMM TASK 71-13-00-010-040)
(1) FOR [1000EM1] (ENGINE-1)
437AL 438AR
(2) FOR [1000EM2] (ENGINE-2)
447AL 448AR

Subtask 74-21-20-040-053-A ** ON A/C NOT FOR ALL

D. Make the thrust reverser unserviceable (Ref. AMM TASK 78-30-00-481-041).

Subtask 74-21-20-010-057-A ** ON A/C NOT FOR ALL

E. Open the thrust reverser doors: (Ref. AMM TASK 78-36-00-010-040)
(1) FOR [1000EM1] (ENGINE-1)
451AL 452AR
(2) FOR [1000EM2] (ENGINE-2)
461AL 462AR

4. Procedure
Subtask 74-21-20-020-059-A ** ON A/C NOT FOR ALL

A. Disconnect the left ignition lead connector (Ref. AMM TASK 74-21-20-000-002).

Subtask 74-21-20-100-051-A ** ON A/C NOT FOR ALL

B. Clean the ceramic insulator and contact with lint free cloth is moist with CP10111,1,1 trichlorethane or Stoddard Solvent.

Subtask 74-21-20-210-051-A ** ON A/C NOT FOR ALL

C. Inspection of Left Ignition Lead:

NOTE: Type 3 (PRE SB 74-002) igniter plug connectors use a white chamfered silicone seal and a caged spring assembly.
Type 4 (POST SB 74-002) igniter plug connectors use a blue symmetrical silicone seal and a captive spring assembly.

INSPECT/CHECK	MAXIMUM SERVICEABLE LIMITS	REMARKS
1.Type 3 and 4 exciter connector for :
Carbon tracks.	Not serviceable.	Replace lead (Ref. AMM TASK 74-21-20-000-002) and (Ref. AMM TASK 74-21-20-400-002).
Thread damage.	30 percent of lead-in thread or 10 percent on each of 2 lead-in threads may be missing after chasing.	Chase threads or replace lead (Ref. AMM TASK 74-21-20-000-002) and (Ref. AMM TASK 74-21-20-400-002)
CAUTION: DO NOT PULL ON CONTACT AND CERAMIC INSULATOR TO INSPECT THE LEAD WIRE. THIS CAN CRACK THE SILICONE INSULATION OF THE WIRE CREATING AN ARC PATH TO THE INTERNAL SPRING RESULTING IN LEAD FAILURE. 2.Type 3 igniter plug connector for:
Burned or pitted contact.	Not serviceable.	Replace lead (Ref. AMM TASK 74-21-20-000-002) and (Ref. AMM TASK 74-21-20-400-002).
Cracked or chipped ceramic insulator.	Not serviceable.	Replace lead (Ref. AMM TASK 74-21-20-000-002) and (Ref. AMM TASK 74-21-20-400-002).
Thread damage.	30 percent of lead-in thread or 10 percent on each of 2 lead-in threads may be missing.	Chase threads or replace lead (Ref. AMM TASK 74-21-20-000-002) and (Ref. AMM TASK 74-21-20-400-002).
PRE SB 74-002
Damage to caged spring assembly.	Not serviceable.	Repair the lead (Ref. AMM TASK 74-21-20-300-005).
Damaged or missing white silicone seal.	Not serviceable.	Repair the lead (Ref. AMM TASK 74-21-20-300-005).
NOTE: The white and blue silicone seals are not interchangeable.
CAUTION: DO NOT PULL ON CONTACT AND CERAMIC INSULATOR TO INSPECT THE LEAD WIRE. THIS CAN CRACK THE SILICONE INSULATION OF THE WIRE CREATING AN ARC PATH TO THE INTERNAL SPRING RESULTING IN LEAD FAILURE. 3.Type 4 Igniter plug connector for:
Eroded or pitted contact.	Not serviceable.	Repair lead (Ref. AMM TASK 74-21-20-300-004).
Arcing or burning on contact or terminal.	Not serviceable.	Repair lead (Ref. AMM TASK 74-21-20-300-004).
Dimension from contact face to the retaining ring groove.	Not less than 1.40 mm (0.0551 in.).	Repair lead (Ref. AMM TASK 74-21-20-300-004).
Cracked or chipped ceramic insulator.	Not serviceable.	Repair lead (Ref. AMM TASK 74-21-20-300-005).

Thread damage.	Less than 30 percent of first thread is damaged.	Chase the threads.
	Less than 10 percent of second thread is damaged.	Chase the threads.
	Damage is more than the above limits.	Replace lead (Ref. AMM TASK 74-21-20-000-002) and (Ref. AMM TASK 74-21-20-400-002).
POST SB 74-002
Damage to captive spring assembly.	Not serviceable.	Replace lead (Ref. AMM TASK 74-21-20-000-002) and (Ref. AMM TASK 74-21-20-400-002).
Damage or missing blue silicone seal.	Not serviceable.	Repair the lead (Ref. AMM TASK 74-21-20-300-005).
NOTE : The white and blue silicone seals are not interchangeable.
4.Type 3 and 4 igniter lead braided conduit for:
Chafing along the entire length of the ignition lead.	Not serviceable.	Replace lead (Ref. AMM TASK 74-21-20-000-002) and (Ref. AMM TASK 74-21-20-400-002).
NOTE: The left hand ignition lead can chafe on the 2 o'clock VSV actuator bellcrank. This damage can prevent cooling air flow to the igniter plug end of the ignition lead. The loss of cooling air can breakdown the insulation of the ignition lead and decrease the life of the head and plug.
Broken strands.	Less than half of the circumference by 25.4 mm (1.0000 in.) in length is permitted.	Replace lead (Ref. AMM TASK 74-21-20-000-002) and (Ref. AMM TASK 74-21-20-400-002).
	Less than 25.4 mm (1.0000 in.) in length within any 76.2 mm (3.0000 in.) of lead.	Replace lead (Ref. AMM TASK 74-21-20-000-002) and (Ref. AMM TASK 74-21-20-400-002).
	Total damage can not be more than 10 percent of the total length of the lead.	Replace lead (Ref. AMM TASK 74-21-20-000-002) and (Ref. AMM TASK 74-21-20-400-002).
	No damage to conduit under the strands.	Replace lead (Ref. AMM TASK 74-21-20-000-002) and (Ref. AMM TASK 74-21-20-400-002).
Braze joint separation.	Not serviceable.	Replace lead (Ref. AMM TASK 74-21-20-000-002) and (Ref. AMM TASK 74-21-20-400-002).
Sharp bends.	Maximum 152.4 mm (6.0000 in.) bend radius.	Reposition the lead to eliminate sharp bend.
5.Type 3 and 4 cooling shroud for :
Obstruction at exit holes.	Not serviceable.	Remove the obstruction.
6.Type 3 and 4 ignition lead chafe guard for :
Cuts and/or tears.	Not serviceable.	Repair lead (Ref. AMM TASK 74-21-20-300-006).

Subtask 74-21-20-420-059-A ** ON A/C NOT FOR ALL

D. Connect the left ignition lead connection (Ref. AMM TASK 74-21-20-400-002).

5. Close-up
Subtask 74-21-20-410-055-A ** ON A/C NOT FOR ALL

A. Close Access
(1) Make sure that the work area is clean and clear of tools and other items.
(2) Close the thrust reverser doors: (Ref. AMM TASK 78-36-00-410-040)
(3) FOR [1000EM1] (ENGINE-1)
451AL 452AR
(4) FOR [1000EM2] (ENGINE-2)
461AL 462AR

Subtask 74-21-20-440-052-A ** ON A/C NOT FOR ALL

B. Make the thrust reverser serviceable (Ref. AMM TASK 78-30-00-081-041).

Subtask 74-21-20-410-056-A ** ON A/C NOT FOR ALL

C. Close Access
(1) Close the fan cowl doors: (Ref. AMM TASK 71-13-00-410-040)
(a) FOR [1000EM1] (ENGINE-1)
437AL 438AR
(b) FOR [1000EM2] (ENGINE-2)
447AL 448AR
(2) Remove the WARNING NOTICE(S).

Subtask 74-21-20-865-059-A ** ON A/C NOT FOR ALL

D. 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	ENGINE/1 AND 2/IGN/SYS A	1JH	A03
FOR FIN: 1000EM1 (ENGINE1)
121VU	ENGINE/IGN/ENG1/SYS B	3JH1	P41
121VU	ENGINE/IGN/ENG1/SYS A BAT	2JH1	P39
FOR FIN: 1000EM2 (ENGINE2)
121VU	ENGINE/IGN/ENG2/SYS B	3JH2	P42
121VU	ENGINE/IGN/ENG2/SYS A BAT	2JH2	P40

[Rev.10 from 2021] 2026.04.01 03:07:42 UTC