Inspection of Mid Acoustical Panels [CFMB]

TASK 72-23-00-280-006-A
Inspection of Mid Acoustical Panels

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

B. Referenced Information

REFERENCE	DESIGNATION
TASK 72-00-00-200-025-A	Over-Serviceable-Limit Extensions
TASK 72-00-00-200-025-A-01	Over-Serviceable-Limit Extensions
TASK 72-21-00-000-005-A	Removal of the Spinner Front Cone
TASK 72-21-00-000-006-A	Removal of the Spinner Rear Cone
TASK 72-21-00-000-007-A	Removal of the Fan Rotor Blades
TASK 72-21-00-400-005-A	Installation of the Spinner Front Cone
TASK 72-21-00-400-006-A	Installation of the Spinner Rear Cone
TASK 72-21-00-400-007-A	Installation of the Fan Rotor Blades
TASK 72-23-00-000-025-A	Removal of the Mid Acoustical Panels
TASK 72-23-00-300-044-A	Repair of Forward, Mid and Aft Acoustical Panels when Unbonded Cup
TASK 72-23-00-400-025-A	Installation of the Mid Acoustical Panels
TASK 72-23-00-400-044-A	Installation of Acoustical Panels Attachment Screw Locking
Fan Acoustical Panels

3. Job Set-up
Subtask 72-23-00-941-091-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 72-23-00-010-113-A ** ON A/C NOT FOR ALL

B. Get Access
(1) Put an ACCESS PLATFORM 1M(3 FT) in position at the front of the engine.
(2) Remove the spinner front cone (Ref. AMM TASK 72-21-00-000-005).
(3) Remove the spinner rear cone (Ref. AMM TASK 72-21-00-000-006).
(4) Put a temporary mark on each fan blade from 1 to 36.
(5) Remove 3 consecutive fan blades (Ref. AMM TASK 72-21-00-000-007).
To compensate for imbalance caused by the removal of 3 blades, it is recommended to remove 3 blades 180-degrees opposite to those removed before.

4. Procedure
Subtask 72-23-00-350-059-A ** ON A/C NOT FOR ALL

A. Inspection of Mid Acoustical Panels

INSPECT/CHECK	MAXIMUM SERVICEABLE LIMITS	REMARKS
1.Leading edge delamination	Not serviceable	Replace panel (Ref. AMM TASK 72-23-00-000-025) and (Ref. AMM TASK 72-23-00-400-025).
2.Inner skin delamination in acoustical area	20 percent of acoustical area	Above 20 percent, replace panel (Ref. AMM TASK 72-23-00-000-025) and (Ref. AMM TASK 72-23-00-400-025).
3.Mid acoustical panel cups
A.Dents, marks, indentations caused by screw head	No limits
B.Pierced cups caused by screw head	No limits	(Ref. AMM TASK 72-23-00-400-044)
C.Unbonded cups	Not serviceable	(Ref. AMM TASK 72-23-00-300-044)
D.Missing cups.	Not serviceable	(Ref. AMM TASK 72-23-00-300-044)
4.Missing panel	Not serviceable
5.Loose bolts	Not serviceable	Tighten bolts.
6.Subsurface linear impressions or wrinkles	No limits	Serviceable criteria applied on new parts.
7.Voids	Five per panel, 2 in. (50.8 mm) apart, 0.12 in. (3 mm) Dia max., 0.012 in. (0.3 mm) max. depth	Serviceable criteria applied on new parts.
8.Defects in the protective coating (initial Tedlar film, or paint) such as:
A.Missing	No limits	Remove the loose material with a sharp blade.
B.Defects (dents, nicks, tears, flaking) that let show the inner skin	No limits	Remove the loose material with a sharp blade.
9.Inner skin defects, such as:
A.Superficial defects (dents, nicks, tears, impact marks) not through the skin	No limits with a total surface area less than 4 square in. (2580 sq mm) per panel	Remove the loose material with a sharp blade.
B.Defects (tears, cracks, punctures) through the skin	Not serviceable	Replace panel(s) (Ref. AMM TASK 72-23-00-000-025) and (Ref. AMM TASK 72-23-00-400-025).
C.Stiffener delamination under panel leading edge	Sound not constant with adjacent area by tap test control. Do the tap test control on the first 0.83 in. (21 mm) area from the leading edge on assembled panels	Replace panel(s) (Ref. AMM TASK 72-23-00-000-025) and (Ref. AMM TASK 72-23-00-400-025).
10.Damper
A.Cracks (if panel removed)	Any amount
B.Disbonded damper (if panel removed)	Any amount not more than 20 percent of the total bonded surface	Replace mid acoustical panels that are not in the limits (Ref. AMM TASK 72-23-00-000-025) and (Ref. AMM TASK 72-23-00-400-025). Refer to the over-serviceable limit extensions (Ref. AMM TASK 72-00-00-200-025).

5. Close-up
Subtask 72-23-00-410-104-A ** ON A/C NOT FOR ALL

A. Close Access
(1) Install the fan rotor blades at the locations recorded at the removal (Ref. AMM TASK 72-21-00-400-007).
(2) Install the spinner rear cone (Ref. AMM TASK 72-21-00-400-006).
(3) Install the spinner front cone (Ref. AMM TASK 72-21-00-400-005).
(4) Make sure that the work area is clean and clear of tools and other items.
(5) Remove the ACCESS PLATFORM 1M(3 FT).
(6) Remove the WARNING NOTICE(S).

[Rev.10 from 2021] 2026.04.01 02:41:54 UTC