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Modification of Canadian Aircraft

What is a design change
The maintenance release for a modification design change
The AC 43.13 as specified data for major modifications
Approved data for major modifications
How do you obtain a design change approval
What is a DAR and a DAO
Why use a DAR or DAO
Standards and Approvals

But the item has a TSO (Technical Standard Order) why can’t I just bolt it in? Have you heard this or though this? It is a common misconception.

We function together as humans because of standards. A red light means stop, you can read this because we share a language standard. A TSO is a construction standard. A TSO’ed item means that the item has been manufactured to some defined standard. This is good but now you want to install the item in your certified aircraft. If the item is a new installation it will have to comply with the design standards of the aircraft. That is the standards or regulations that the aircraft was certified to. This means a design change approval such as a STC LSTC or a PDA. Think of it this way, the TSO states the standard to which the item was constructed to and the design change approval states that TSO item and installation comply with the standards of the aircraft.

So can you install non-TSO’ed items on an aircraft? Sure, however, this will be more work and it will have to be insured that the non-TSO’ed item complies with all the pertinent certification requirements for the installation.

Do you always need an approval to install a TSO’ed? Not always. Obviously if the item is the same as the item removed no approval is needed. If the item is a new installation and the installation can be classified as a minor modification acceptable data may be used if available. If the item is a new installation and the installation is classified as a major modification specified data may be used if available.

Mechanics, Engineers and good design
Whose responsibility is the aircraft modification
Change Product Rule and the basis of certification