Part V - Standard 571 Appendix A - Criteria for the Classification of Modifications and Repairs
Canadian Aviation Regulations (CARs) 2019-1
Content last revised: 2002/06/01
The following criteria outline a decision process for assessing the classification of a modification or repair.
For each issue it shall be determined whether the modification or repair to be accomplished could have other than a negligible effect on those characteristics contained in the definitions of "Major Modification" and "Major Repair", pursuant to section 571.06 of this standard. The following questions are answered with either a YES or NO response. A YES answer to any individual question indicates that the modification or repair shall be classified major.
(a) Operating Limitations
Does the modification or repair involve a revision in the operating limitations specified in the approved type design?
(b) Structural Strength
The questions contained in this paragraph shall be applied to alterations of an airframe, engine, propeller, or component.
Does the modification or repair alter:
(1) a principal component of the aircraft structure such as a frame, stringer, rib, spar, skin or rotor blade?
(2) a life-limited part or a structural element that is subject to a damage tolerance assessment or fail-safe evaluation?
(3) the strength or structural stiffness of a pressure vessel?
(4) the mass distribution in a structural element?
This might involve the installation of an item of mass that would necessitate a structural re-evaluation.
(5) a containment or restraint system intended for occupants or the storage of items of mass (e.g. cargo)?
(6) the structure of seats, harnesses, or their means of attachment?
(c) Powerplant Operation
Does the modification or repair:
(1) affect the power output or control qualities of the powerplant, engine, propeller, or their accessories?
(2) alter the approved operating limitations?
(d) Performance and Flight Characteristics
Does the modification or repair involve alterations that:
(1) significantly increase drag or exceed aerodynamic smoothness limits?
(2) significantly alter thrust or power output?
(3) affect stability or controllability?
(4) induce flutter or vibration?
(5) affect the stall characteristics?
(e) Other Qualities Affecting Airworthiness
Does the modification or repair:
(1) change the information on, or the location of, a placard required by the type design or an Airworthiness Directive?
(2) alter any information contained in the approved section of the aircraft flight manual or equivalent publication?
(3) affect the flight-crew's visibility or their ability to control the aircraft?
(4) affect egress from the aircraft?
(5) reduce the storage capacity of an oxygen system, or alter the oxygen rate of flow?
(6) affect flight controls or an autopilot?
(7) alter an electrical generation device, or the electrical distribution system between the generating source and either its primary distribution bus, or any other bus designated as an essential bus?
The electrical distribution system includes its associated control devices, and all its protection devices.
(8) reduce the storage capacity of the primary battery?
(9) affect a communication system required by the approved type design?
(10) affect instruments, or indicators that are installed as part of a system required by the approved type design?
(f) Other Qualities Affecting Environmental Characteristics
Does the modification or repair increase aircraft noise levels or emissions?