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Critical Design Configuration Control Limitations (CDCCL)


CDCCL – Critical Design Configuration Control Limitations identify the critical design features such as proper wire separation, proper installation of a panel gasket, minimum bonding jumper resistance levels, etc., that must be maintained in exactly the same manner throughout the life of the aircraft in order to comply with the type certificate and maintain airworthiness.

The purpose of the Critical Design Configuration Control Limitation (CDCCL) is to provide instructions to ensure these critical features are present throughout the life of the airplane and are Inspected and verified when alterations, repairs, or maintenance actions occur in the area.

Related to SFAR 88

Design features that are CDCCLs are defined and controlled by Special Federal Aviation Regulation (SFAR) 88 and preserves critical features of the airplane needed for the Flammability Reduction Means (FRM) or IMM to perform their intended function and prevent the occurrence of an unsafe condition.

 Mandatory Airworthiness Limitations

CDCCL’s are a type of Airworthiness Limitation and 14 CFR 43.16 makes it mandatory for the AMT’s and Aircraft Operators to comply with all Airworthiness Limitations.

CDCCLs are mandatory,  FAA approved and cannot be changed or deleted without the approval of the FAA office that is responsible for the airplane model Type Certificate, or applicable regulatory agency.

CDCCL’s must be accomplished in exactly the same manner as specified in the AMM Any use of parts, methods, techniques or practices different than what is written in the CDCCL must be approved by the FAA ACO that is responsible for the airplane model Type Certificate . Any maintenance actions or subsequent changes to the product made by operators or the manufacturer MUST NOT DEGRADE the level of safety of the original type design.

CDCCL’s cannot be deferred or carried over. There are no extensions available to comply with any CDCCL at a later date and the aircraft cannot operate without being in compliance with the condition and design features specified.

No Set Inspection Interval

A CDCCL Inspection has no time or cycle interval. Whenever maintenance is being performed in the area applicable to the CDCCL the inspection must be accomplished regardless of where the aircraft is located .Whether the aircraft is at the gate with passengers loaded or is undergoing heavy maintenance it makes no difference to the requirement. The CDCCL must be accomplished.

Critical Design Limitation Control Limitations are one of three system airworthiness limitations. One is an ALI inspection that has a specific task and interval, such as 10 years. A second type is ALI procedures that could have specific task intervals. The third type is the CDCCL that has no interval but establishes configuration limitations to maintain and to protect the “critical design feature” identified.

CDCCL’s Are Not CMR’s – Certification Maintenance Requirements (CMR) only address mandatory maintenance that is applied to the airplane at the time of original certification. The rule for CDCCL’s addresses not only MANDATORY maintenance actions, but also design features that cannot be ALTERED except in accordance with the Instructions for Continued Airworthiness (ICA).

What are some typical tasks that involve CDCCL inspections?

  • Fuel Tank Panel Replacement
  • Heat Exchanger Removal & Replacement
  • Accessing areas floorboards in the the vicinity of fuel tanks
  • Resetting  tripped fuel pump circuit breakers
  • Engine fuel valve replacement
  • Passenger Cabin floor Panel Installation
  • Flame Arrestor Installation


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