Detailed Inspection of the Forward Engine Mount [CFMB]

TASK 71-21-11-210-040-B
Detailed Inspection of the Forward Engine Mount

1. Reason for the Job
Refer to the MPD TASK: 712111-01
DETAILED INSPECTION OF FORWARD ENGINE MOUNT INSTALLATION
This inspection criteria is only for those parts of the engine that you can see when the engine is installed on an airplane. The limits and remarks are not applicable to the areas of the mount that you cannot see when the engine is installed.
2. Job Set-up Information
A. Fixtures, Tools, Test and Support Equipment

REFERENCE	QTY	DESIGNATION
No specific	AR	ACCESS PLATFORM 1M(3 FT)
No specific	AR	WARNING NOTICE(S)

B. 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

C. 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 71-21-11-000-041-A	Removal of the Forward Engine Mount System
TASK 71-21-11-000-045-A	Removal of the Forward Engine Mount Bolts One at a Time
TASK 71-21-11-400-041-A	Installation of the Forward Engine Mount System
TASK 71-21-11-400-045-A	Installation of the Forward Engine-Mount Bolts, One at a Time
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
CMM 712108
Forward Engine Mount
Forward Engine Mount Support Beam
Forward Engine Mount Cross Beam
Forward Engine Mount Link

3. Job Set-up
Subtask 71-21-11-941-056-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 71-21-11-010-055-A ** ON A/C NOT FOR ALL

B. Get Access
(1) Open the fan cowl doors (Ref. AMM TASK 71-13-00-010-040):
(2) FOR [1000EM1] (ENGINE-1)
437AL 438AR
(3) FOR [1000EM2] (ENGINE-2)
447AL 448AR
(4) Put the ACCESS PLATFORM 1M(3 FT) in position.

Subtask 71-21-11-040-051-A ** ON A/C NOT FOR ALL

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

Subtask 71-21-11-010-057-A ** ON A/C NOT FOR ALL

D. 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 71-21-11-210-052-A ** ON A/C NOT FOR ALL

A. Visual Inspection of the Forward Engine Mounts
(1) Do a detailed visual inspection of the forward engine mount. Clean any dirt or unwanted material from the forward engine mount with a clean cloth. Use a flashlight and an inspection mirror to examine areas of the engine mount that are hard to see.
(2) Do this inspection on those areas of the forward engine mount that are visible without the removal of any hardware.
Visually examine for cracks. Give special attention to critical areas:

Forward Engine Mount Support Beam ** ON A/C NOT FOR ALL

Forward Engine Mount Cross Beam ** ON A/C NOT FOR ALL

Forward Engine Mount Link ** ON A/C NOT FOR ALL

INSPECT/CHECK	MAXIMUM SERVICEABLE LIMITS	REMARKS
1.Examine the two halves of the main beam, look for: Forward Engine Mount Support Beam ** ON A/C NOT FOR ALL
A.Cracks	None permitted	If cracks are found, replace the mount assembly (Ref. AMM TASK 71-21-11-000-041) and (Ref. AMM TASK 71-21-11-400-041). Note: Discard the damaged part and inspect the mount assembly per CMM 712108 Inspection/Check procedure.
2.Examine the cross beam, look for: Forward Engine Mount Cross Beam ** ON A/C NOT FOR ALL
A.Cracks	None permitted	If cracks are found, replace the mount assembly (Ref. AMM TASK 71-21-11-000-041) and (Ref. AMM TASK 71-21-11-400-041). Note: Discard the damaged part and inspect the mount assembly per CMM 712108 Inspection/Check procedure.
3.Examine the two links on the mount, look for: Forward Engine Mount Link ** ON A/C NOT FOR ALL
A.Cracks	None permitted	If cracks are found, replace the mount assembly (Ref. AMM TASK 71-21-11-000-041) and (Ref. AMM TASK 71-21-11-400-041). Note: Discard the damaged part and inspect the mount assembly per CMM 712108 Inspection/Check procedure.
4.Examine the forward engine mount bolts, look for:
A.Cracks	None permitted	If a bolt is cracked, replace the bolt (Ref. AMM TASK 71-21-11-000-045) and (Ref. AMM TASK 71-21-11-400-045).
B.Damaged threads	None permitted	If the threads are damaged, replace the bolt (Ref. AMM TASK 71-21-11-400-045) and (Ref. AMM TASK 71-21-11-000-045).

NOTE: For all other findings (nick, scratch, gouge...), please refer to CMM 712108 Inspection/Check procedure.

5. Close-up
Subtask 71-21-11-410-056-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 71-21-11-440-051-A ** ON A/C NOT FOR ALL

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

Subtask 71-21-11-410-058-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 access platform(s).
(3) Remove the WARNING NOTICE(S).

[Rev.10 from 2021] 2026.04.01 02:26:04 UTC