Detailed Inspection of FWD Engine Mount Installation [IAE]

TASK 71-21-12-200-010-A
Detailed Inspection of FWD Engine Mount Installation

WARNING: BE CAREFUL WHEN YOU USE CONSUMABLE MATERIALS. OBEY THE MATERIAL MANUFACTURER'S INSTRUCTIONS AND YOUR LOCAL REGULATIONS.

ZONE: 400

1. Reason for the Job
Refer to the MPD TASK: 712111-03
DETAILED INSPECTION OF FORWARD ENGINE MOUNT INSTALLATION
This TASK gives the data for a detailed inspection of the forward engine mount with or without engine removal.

NOTE: The effectivity of this task is "ALL". To know if this task is applicable for your aircraft, refer to the MPD task applicability and the weight variant data given in the SRM introduction.

2. Job Set-up Information
A. Fixtures, Tools, Test and Support Equipment

REFERENCE	QTY	DESIGNATION
No specific	1	ACCESS PLATFORM 2M (6 FT)
No specific	1	LIGHT SOURCE - INSPECTION
No specific	1	MIRROR - INSPECTION
No specific	AR	WARNING NOTICE(S)

B. Consumable Materials

REFERENCE	DESIGNATION
(Material No.V01-002)	cleaning fluid
(Material No.14SBA1)	Textile-Lint free Cotton -

C. Work Zones and Access Panels

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

D. Referenced Information

REFERENCE	DESIGNATION
TASK 71-13-00-010-010-A	Opening of the Fan Cowls 437AL(447AL),438AR(448AR)
TASK 71-13-00-410-010-A	Closing of the Fan Cowls 437AL(447AL),438AR(448AR)
TASK 71-21-12-000-010-A	Removal of the Forward Engine Mount Bolts One at a Time
TASK 71-21-12-400-010-A	Installation of the Forward Engine Mount Bolts One at a Time
TASK 78-30-00-040-012-A	Deactivation of the Thrust Reverser Hydraulic Control Unit (HCU) for Ground Maintenance
TASK 78-30-00-440-012-A	Re-activation of the Thrust Reverser Hydraulic Control Unit (HCU) after Ground Maintenance
TASK 78-32-00-010-010-A	Opening of the Thrust Reverser Halves
TASK 78-32-00-410-010-A	Closing of the Thrust Reverser Halves
CMM 712112
Forward Engine Mount

3. Job Set-up
Subtask 71-21-12-941-050-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 71-21-12-010-050-A ** ON A/C NOT FOR ALL

B. Get Access
(1) Open the fan cowls (Ref. AMM TASK 71-13-00-010-010):
(a) FOR [1000EM1] (ENGINE-1)
437AL, 438AR
(b) FOR [1000EM2] (ENGINE-2)
447AL, 448AR.
(2) Put an ACCESS PLATFORM 2M (6 FT) in position.

Subtask 71-21-12-040-050-A ** ON A/C NOT FOR ALL

C. Deactivate the thrust reverser hydraulic control unit (HCU) (Ref. AMM TASK 78-30-00-040-012).

Subtask 71-21-12-010-051-A ** ON A/C NOT FOR ALL

D. Open the thrust reverser halves (Ref. AMM TASK 78-32-00-010-010):
(1) FOR [1000EM1] (ENGINE-1)
451AL, 452AR
(2) FOR [1000EM2] (ENGINE-2)
461AL, 462AR.

Subtask 71-21-12-110-050-A ** ON A/C NOT FOR ALL

E. Clean the Forward Engine Mount.
(1) Clean the forward engine mount with a Textile-Lint free Cotton - (Material No.14SBA1) made moist with cleaning fluid (Material No.V01-002) .

4. Procedure
Subtask 71-21-12-210-050-A ** ON A/C NOT FOR ALL

A. Examine the Forward Engine Mount (Refer to Table 601 for allowable damage limits)

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

(1) Visually examine the forward engine mount beam assembly (7) immediately aft of the monoball assembly (6) for cracks and corrosion. Use an MIRROR - INSPECTION and LIGHT SOURCE - INSPECTION (Ref. Detail B).
(2) Visually examine the right and left thrust links (3) for corrosion and cracks, mainly the circumference of the lug areas (180 deg. of the lug end).

NOTE: The full circumference of the lugs may not be visible using an inspection mirror and lamp.

(3) Visually examine the cross beam (1) for cracks.
(4) Visually examine, as far as possible, the mount beam assembly (7) for cracks and corrosion. Examine mainly the circumference of the crossbeam attachment lug (180 deg.).
(5) Visually examine, as far as possible, the engine thrust link attach brackets (5) for cracks and corrosion.
(6) Visually examine all of the anti-rotation and retainer plates (4) for corrosion, any obvious damage and correct installation.
(7) Visually examine the thrust link shear pin assemblies (2) as far as possible for cracks and corrosion.
(8) Visually examine the forward engine mount bolts, washers and nuts (8). If a crack is found on one of the bolts or nuts (8), all five bolts, washers and nuts (8) must be replaced. If any damage is found on a washer (8), replace the damaged washer (8) (Ref. AMM TASK 71-21-12-000-010) and (Ref. AMM TASK 71-21-12-400-010).

Table 601: List of Allowable Damage Limits

DAMAGE	ALLOWABLE DAMAGE LIMITS
Corrosion	Discoloration caused by corrosion is acceptable provided there is no pitting or a reduction in the cross-sectional area of the component.
Cracks	No cracks are allowed.
Gouges, nicks, scratches and other surface damages	Refer to CMM 712112.

5. Close-up
Subtask 71-21-12-410-050-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 halves (Ref. AMM TASK 78-32-00-410-010):
(a) FOR [1000EM1] (ENGINE-1)
451AL, 452AR
(b) FOR [1000EM2] (ENGINE-2)
461AL, 462AR.

Subtask 71-21-12-440-050-A ** ON A/C NOT FOR ALL

B. Activate the thrust reverser HCU (Ref. AMM TASK 78-30-00-440-012).

Subtask 71-21-12-410-051-A ** ON A/C NOT FOR ALL

C. Close Access
(1) Close the fan cowls (Ref. AMM TASK 71-13-00-410-010):
(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 02:30:17 UTC