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AAC NO. 4 of 2000

Date: 4th

September 2000

GOVERNMENT OF INDIA

CIVIL AVIATION DEPARTMENTDIRECTOR GENERAL OF CIVIL AVIATION

AIRWORTHINESS

ADVISORY CIRCULAR

SUBJECT: MAINTENANCE OF AGING AIRCRAFT__________________________________________________________________

PURPOSE: This Advisory Circular is intended to provide guidelines for the maintenance

of all aircraft including private aircraft which have crossed 20 years since manufacture.

BACKGROUND: There have been instances wherein aircraft were involved in incidents

due to failure of significant structural item of the aircraft. To take care of the continuedairworthiness of such structural items manufacturers have issued

a) Service Bulletins (SBs) requiring structural inspection of specific areas at certainintervals,

b) Supplemental Structural Inspection Document (SSID)c) Aging Aircraft Repair and Modification Programme

d) Corrosion Prevention and Control Programme (CPCP)e) Repair Assessment Programme (RAP), etc.

In some of the cases, SBs calling for structural inspections have been declaredmandatory by DGCA based on the Airworthiness Directives issued by the Regulatoryauthority of the country of Manufacture. Further, SSID, CPCP, and Aging aircraftRepair and Modification Programme have also been made mandatory by DGCA.

Notwithstanding the above, it has been considered prudent to subject such of thoseaircraft which have crossed 20 years since manufacture to frequent structuralinspections as given in the Manufacturer's Maintenance Planning Document (MPD) orany other equivalent document.

PROCEDURES: To ensure continued structural integrity of all aircraft including private

aircraft, which have crossed 20 years, the following procedures be followed:

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1. The C of A be renewed every six months as against normal validity of twelvemonths. Aircraft need not be subjected to test flight during every renewal. However,

the test flight wherever applicable shall be carried out annually as per the

requirements given in CAR Section 2, Series 'T' Part II. The aircraft may also besubjected to test flight any time as required in the above said CAR.

2. The items of structural inspection as given in the MPD/Manufacturer's Document

and included in the approved routine schedule higher than flight release schedule,be subjected to frequent inspection by reducing the inspection intervals by 20%.

3. All structural inspections required to be complied as per SSID, CPCP, Aging AircraftProgramme, DGCA mandatory modifications may continue to be carried out at the

threshold given in the relevant documents, such as, SBs/ADs, SSID, CPCP, AgingAircraft Programme, etc.

4. Life of major components should be closely monitored to ensure that the lifeapproved by DGCA is achieved. If it is observed that there is a wide variationbetween the approved life and the average life achieved, in which case, theapproved life should be down graded to the average life achieved. Otherwise, the

exact reason for reduction in the approved life should be analyzed and appropriatesteps taken in the form of compliance of SBs, procurement of spares from reputedsources, refresher training of personnel to improve the quality of workmanship etc.so that the approved life is achieved.

5. All minor and major defects should be thoroughly analysed and exact reason as to

the cause of the defect established. Appropriate corrective action should be taken toensure that the defects are not repeated and the occurrence of defects minimised.Major defects should be promptly reported to DGCA

Sd/-(L.A.Mahalingam)

Director of AirworthinessFor Director General of Civil Aviation

Note: This Advisory Circular supercedes Advisory Circular No. 3 of 1997 in its entirety.