Introduction Continuing Airworthiness Concepts related to Structural Integrity

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Sofema Aviation Services (SAS) www.sassofia.com considers the need for the industry to manage structural integrity in compliance with AMC4 CAMO.A.305(g) Personnel requirements (ED Decision 2020/002/R) - Related to AMC 20-20 ‘Continuing Structural Integrity Programme’

Sofema Aviation Services offers the following training in support of the understanding regarding the regulatory obligations –

https://sassofia.com/course/amc-20-20-continuing-structural-integrity-programme-1-day/

Historical Background Continuing Airworthiness & Structural Integrity

Continuing Airworthiness Concerns for aging jet transports has received much attention over the last 15 - 20 years.

Boeing and other TCH’s developed Supplemental Structural Inspection Programs.

In the late1970’s and early 1980’s intended to address fatigue problems. And much focus was placed on fail-safe structural designs.

The aloha incident became a milestone in respect of understanding the effects of widespread fatigue damage.

Whilst Boeing initiated aging fleet surveys by engineering teams in the mid-1980s, The Aloha explosive decompression incident became a milestone in respect of understanding the effects of widespread fatigue damage. See here for details https://en.wikipedia.org/wiki/Aloha_Airlines_Flight_243

Primary Driver for Structural Integrity

The primary method of driving Structural integrity relies on

  • Operator feedback together with
  • Service Bulletin SB reviews and
  • Mandatory Inspections (Sometimes AD driven sometimes Alert Service Bulletin Driven ASB).

Note - Previously structural airworthiness integrity was wholly dependent on repetitive inspections. Aging airplane concerns prompted a reassessment of the viability of repetitive inspections as a mechanism of protection.

MSG-3 Maintenance Review Board – Objectives

The goal for the MRB structures working group is to preload integrity into the structure not rely on inspecting, fix, report, followed by SB action and fleet campaigns.

Across the worlds fleets an accumulation of knowledge and experience has benefited current designs by an order of magnitude.

Corrosion Prevention and Control Programs (CPCP) were built into MSG3 programs. As we are aware If left unchecked corrosion has the potential to weaken the structure which can lead to fatigue cracking, and a deterioration in Structural Integrity.

The individual characteristics of the CPCP programs vary between models and TCH but all follow the same basic principles to deliver an effective and managed approach to ensure all necessary areas are accessed inspected and treated in the approved manner.

to deliver EASA Continuing Airworthiness Related to Aircraft Structures in an effective way will require Procedures to ensure a full understanding of the mechanics of the purpose process and techniques to be used to ensure effective treatment is provided.

It is an unfortunate fact of life that Aircraft gather repairs with many of them being associated with ground damage. The Structure Repair Manual SRM is the first step in assessing any newly found damage.

The SRM contains many standard types of repairs that may be performed, with larger repairs being managed by Part 21 approved organizations.

Whilst the primary need is for repairs to be compliant with the need for both static strengths and fail-safe attributes.

Increasingly when considering continuing airworthiness aspects, there is a need for ongoing inspection to ensure future detection of any deterioration. (is the existing MSG3 inspection process sufficient).

Repairs assessment thresholds are normally based on fatigue damage considerations and specified for each aircraft model usually in Fight cycles or Hours

Typically varying between manufacturers, they are usually some based on  75% of design service objectives and range from 15,000 to 60,000 Airframe Hours (AFH)  (depending on whether the operation is short haul or long haul).

The MSG3 analysis process includes assessments for environmental, accidental, and fatigue damage as part of the Structures Working Group.

Damage detection is a critical element of maintaining damage tolerance assurance with training and knowledge being an essential element of the process how is your organization or maintainer managing the competencies of the inspection staff.

Please see the following related to Part CAMO Transition Support - https://sassofia.com/download-area/#part-camo-transition-support

For additional questions or to register please email team@sassofia.com

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