Major Repair or Major Modification?

[Mighty 150 Flyer]

I've been looking throught TC's website looking for the definition
of a major repair or modification, can't find it. Anyone know what the definition is ? Or even better provide a link. Thx

[carholme]

There is a lot of information at the TC site but here is a link to a brief idea of what it entails.

http://www.canlii.org/ca/regu/sor96-433/sec571.06.html

carholme

[MCRS]

Dictionary:
Repair - fix; mend, make ammends for
modification - change or limit slightly
Modification I would assume from a TC stand point is a change to the original design of the product. ie a ski tray in the tail section of a Beaver, Change of the Engine type of Piston to Turbine.
Repair - So repair would be just that ie. Wing Spar needs replacement because it's been cracked, Need to replace a Bathtub fitting. I am also lumping in the rapairs that require major patches Engineering drawings..... As long as it doesn't change the Original intent of the product as I understand it. Maybe I am still unclear but hope not!

Appears I stand corrected by BR's post below. Well you learn something new everyday. Thanks for the research and enlightenment for us Non structural types!

[Bullet Remington]

Canadian Aviation Regulations (CARs)
Part V - Airworthiness



Standard 571 Appendix A - Criteria for the Classification of Modifications and Repairs
Content last revised: 2002/06/01


(1) General

The following criteria outline a decision process for assessing the classification of a modification or repair.

Information Note:

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.

(2) Criteria

(a) Operating Limitations

Does the modification or repair involve a revision in the operating limitations specified in the approved type design?

(b) Structural Strength

Information Note:

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?

Information Note:

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?

Information Note:

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?

(amended 2002/06/01; previous version)



Return to previous page

571.06 Repairs and Modifications
(1) The following definitions apply to this section:
“major modification” - as per the definition found in Subpart 101 of the CARs.
(amended 2000/12/01; previous version)
Information Note:
For convenience, the Subpart 101 definition is reproduced here.
“major modification” - means an alteration to the type design of an aeronautical product in respect of which a type certificate has been issued that has other than a negligible effect on the weight and centre-of-gravity limits, structural strength, performance, power plant operation, flight characteristics or other qualities affecting its airworthiness or environmental characteristics;
(amended 2000/12/01; previous version)
“major repair” - as per the definition found in Subpart 101 of the CARs.
(amended 2000/12/01; previous version)
Information Note:
For convenience, the Subpart 101 definition is reproduced here.
"major repair" - means a repair to an aeronautical product in respect of which a type certificate has been issued, that causes the aeronautical product to deviate from the type design defined by the type certificate, where the deviation from the type design has other than a negligible effect on the weight and centre-of-gravity limits, structural strength, performance, power plant operation, flight characteristics or other qualities affecting the aeronautical product's airworthiness or environmental characteristics;
(amended 2000/12/01; previous version)

[SeptRepair]

Nice timing for this question. I'm in the middle of installing a mod i consider minor yet i have others thinking it might be major. I'm installing NAT external speakers on a 206 amphibian and i am going to be making a 0.125 2024-t3 plate and installing it over the fueling step picking up the existing holes. The plate will have a slight bend in it to point the speakers straight down. The step will be still functional so in worse case scenario if i was ever to be ramped and have some bullshit inspector give me grief the mod will be quickly removable. The factory step installation has the doubler extending between the upper and lower stringer so the structural strength is there. That step is made to carry at the most a 300lb pilot ( cut me slack, I'm pulling a number off the top of my head on what the fattest pilot out there might weigh, heck even the smallest runt of a pilot out there may only weigh 110lbs soaking wet) so my addition of a 3.85lb weight is negligible. I used the same criteria from CARS and i answered no to all questions in determining if its minor or major. I'm going to go ahead and install the mod and make the log book entry stating what i have done. I cant be bothered to approach transport as we all know they thrive on paper work and ass covering. I would talk to our local DAR but they don't come cheap, in this instance i feel it is unjustified as no approval is needed. Any fellow AME's out there see any problem with this?

[carholme]

SeptRepair;

My personal opinion in that it is outside of the Type Certificate of the aircraft and will involve some additional wiring to an external speaker, you are at the least going to have to submit an LSTC, one to verify the weight carrying ability of the mod and secondly for the addition to the electrical load analysis.

If you can at least give your inspector a call and describe what it is that you are proposing, you may remove any doubt of what is required.

carholme

[CID]

My personal opinion in that it is outside of the Type Certificate of the aircraft and will involve some additional wiring to an external speaker, you are at the least going to have to submit an LSTC, one to verify the weight carrying ability of the mod and secondly for the addition to the electrical load analysis.

There is so much wrong with that statement it's difficult to figure out where to begin so i'll just say completely scrap (ignore) it.

SeptRepair, it's often tricky to figure out if you're dealing with a major or "not major" modification. Minor modifications can be peformed in accordance with "acceptable" data. Major modifications need "approved" or "specified" data. (Refer to CAR 571.06)

Luckily, for a 206, AC 43.13-1 and AC 43.13-2 pass as either acceptable or specified data. The CARS contain the following guidelines for using AC 43 as specified data:

(d) FAA Advisory Circulars AC 43.13-1 and AC 43.13-2, subject to the following conditions:

(i) the aircraft is a small aircraft, and the alteration does not affect dynamic components, rotor blades, structure that is subject to pressurization loads, or the primary structure of a rotorcraft;

(ii) the alteration does not affect an existing limitation (including the information contained on mandatory placards) or change any data contained in the approved sections of the Aircraft Flight Manual, or equivalent;

(iii) the data are appropriate to the product being altered, and are directly applicable to the alteration being made; and,

(iv) the data are not contrary to the aircraft manufacturer’s data.

So do your mod, complete a modification report with a description of the modification and the specific sections of AC 43 that you followed. Make a log book entry and submit a copy of the report to your PMI.

Amend the weight and balance report and electrical load analysis document as required.

One thing to be careful about is any "specialized maintenance" that your modification requires. Having an approval (of any kind) doesn't automatically authorize you to install it if you don't have the appropriate ratings. I don't expect any such problems based on your description but it's a common error so I thought I'd bring it up.

To address the original question, simply put, a "repair" is a process that restored the aircraft's structural integrity. A modification typically adds a function or capability.

[carholme]

SeptRepair;

Sorry for the opinion, I didn't realize that CID was around with his infinite wisdom. I am sure you will figure it out.

carholme

[Cat Driver]

carholme how would you like CID to come to your maintenance shop and do an audit on how you run it?

[carholme]

.;

He is more than welcome anytime.

carholme

[Chuck Ellsworth]

That was not exactly what I was driving at.......

[SeptRepair]

Thanks for the input guys, i can see where Carholme is coming from in a sense. However, i'm at least glad to see CID is thinking along the same lines as myself. Im going to do up the 0045 form ( ya i know its not called that anymore, but you know what i mean.) I was going to use AC 43-13 as my specified data and go with that. My ratings are approriate for the task at hand so im not worried there. Anyways, once again thanks for the opinions.