Visually Examine the Mixed Exhaust System - Allowable Damage Data [IAE]

TASK 78-10-00-200-013-A
Visually Examine the Mixed Exhaust System - Allowable Damage Data

FIN: 1000EM1 ** ON A/C NOT FOR ALL
FIN: 1000EM2 ** ON A/C NOT FOR ALL

1. Reason for the Job
General - Allowable damage data are intended to permit an operator to determine whether a damaged nacelle component may be returned to service without repair. Damage permitted by these data will have no significant effect on the strength or fatigue life of the structure, which will still be able to fulfill its design function. The types of allowable damage permitted are defined and brief descriptions are given of the cleanup procedures needed to either prevent damage propagation or improve the aerodynamic smoothness of the damaged part.
Material Types - The basic material used in the construction of the CNA and the exhaust cone are titanium and aluminium sheet.
Damage - All damage limits assume that exposed edges do not extend above the skin contour. Any such damage should be reworked to remove or feather the extensions. Allowable damage is classified as either unlimited or time limited.

Unlimited usage damage is defined as minor damage which does not affect the structural integrity or functional capability of the component and which needs no repairs over the aircraft design life.
Time limited damage is defined as minor damage which does not affect the structural integrity of the component in normal operation, but could reduce the design life of the component. Therefore, damage must be permanently repaired no later than the next maintenance "C" check. The location and size of the damage is to be noted and checked at each subsequent "A" check to make sure that the damage has not grown beyond the time limited damage allowances.
Damage Types - The types of allowable damage permitted on the CNA components are defined below. They apply only to the parent material and do not include damage to surface finishes such as paint.
Abrasion - An abrasion is a damage area which results in a cross sectional area change because the area was scuffed, rubbed, scraped or had other surface erosion. An abrasion usually appears rough and irregular.
Gouge - A gouge is a damage area of any size which results in a cross sectional area change. It is usually caused by contact with a relatively sharp object which produces a continuous, sharp or smooth channel-like groove in the material.
Nick - A nick is a local gouge with sharp edges. Consider a series of nicks in a line to be a gouge.
Scratch - A scratch is a line of damage in the material and results in a cross sectional area change. It is usually caused by contact with a very sharp object.
Crack - A crack is a partial fracture or complete break in the material and produces a most significant cross sectional area change. It usually appears as an irregular line.
Dent - A dent is damage area which is depressed with respect to its normal contour. There is no change in the cross sectional area. Area boundaries are smooth. Its form is usually the result of contact with a smoothly contoured object.
Hole - A hole is a complete penetration of the material.
This task gives the procedure for the inspection of the mixed exhaust system to determine allowable damage.

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

REFERENCE	QTY	DESIGNATION
No specific	AR	ACCESS PLATFORM 2M (6 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 71-13-00-010-010-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 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
NSRM 544000
Mixed Exhaust System

3. Job Set-up
Subtask 78-10-00-941-053-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 78-10-00-010-056-A ** ON A/C NOT FOR ALL

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

Subtask 78-10-00-040-053-A ** ON A/C NOT FOR ALL

C. Deactivate the Thrust Reverser

WARNING: MAKE SURE THAT THE THRUST REVERSER HYDRAULIC CONTROL UNIT (HCU) IS DEACTIVATED BEFORE YOU DO WORK ON OR AROUND THE THRUST REVERSER. IF THE HCU IS NOT DEACTIVATED, THERE IS A RISK OF UNWANTED THRUST REVERSER OPERATION WHICH CAN CAUSE INJURY TO PERSONS AND/OR DAMAGE TO EQUIPMENT.

(1) Deactivate the thrust reverser Hydraulic Control Unit (HCU) (Ref. AMM TASK 78-30-00-040-012).

Subtask 78-10-00-010-057-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

4. Procedure
Subtask 78-10-00-210-053-A ** ON A/C NOT FOR ALL

A. Examine the Mixed Exhaust System

Mixed Exhaust System ** ON A/C NOT FOR ALL

(1) Any damage.
(a) Refer to NSRM 544000, Common Nozzle Assembly (CNA) and exhaust cone allowable damage, paragraph 3.B., table 101.

5. Close-up
Subtask 78-10-00-410-056-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 halves (Ref. AMM TASK 78-32-00-410-010):
(a) FOR [1000EM1] (ENGINE-1)
451AL 452AR
(b) FOR [1000EM2] (ENGINE-2)
461AL 462AR

Subtask 78-10-00-440-053-A ** ON A/C NOT FOR ALL

B. Activate the Thrust Reverser Hydraulic Control Unit (Ref. AMM TASK 78-30-00-440-012).

Subtask 78-10-00-410-057-A ** ON A/C NOT FOR ALL

C. Close Access
(1) Close the fan cowls doors (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 03:26:59 UTC