to Resource Topics
of Canadian Aircraft
is a design change
The maintenance release for a modification
The AC 43.13 as specified data for
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
Mechanics, Engineers and good design
Whose responsibility is the aircraft
Change Product Rule and the basis
determine the certification requirements for an aeronautical product
design change (the basis of certification) the starting point is
the original certification basis of the aircraft. You can find this
listed on the aircraft’s Type Data Sheet. Think of the basis
of certification like a building code, as time goes on the code
gets more stringent increasing the cost and effort for certification
of new designs. The trade off is increased minimum level of safety
for new designs. The basis of certification is the point in time
(at what amendment level) the design change will comply to.
to the Change Product Rule, which is effect now in CAR 511 and 513,
the design change certification basis was usually always the original
certification basis of the aircraft. Now the Change Product Rule
has to be considered when determining the basis of certification
for a modification. The effect of this is that some modifications
may be required to comply with a more current basis of certification.
This could make some modifications much more costly that they were
in the past.
has this happened you might ask? Imagine that you are an aircraft
manufacture and you wish to develop a new aircraft. Very costly,
at the time of design conception you have to comply with the latest
regulations. So why not take an existing airframe and extensively
modify it creating a new derivative. This new derivative is therefore
not a “new design” but a design change. The basis of
certification remains with the older regulations of the original
aircraft design thus significantly reducing the cost of certification.
This is the practice that the Change Product Rule is aiming at stopping.
now we have the Change Product Rule to make life even more fun.
Airworthiness Manual Advisor AMA 500/16 has been created by Transport
Canada defining a recommended procedure to follow when applying
the Change Product Rule. The interesting part about this is that
it introduces new terms that have to be considered. If you thought
understanding major and minor modification was fun now we have new
terms such as; is the design change “substantial” and
is the design change “significant”. The consolation
is that mechanics will not be exposed to this. The decision of the
basis of certification for a modification is the DAR, DAO or Transport
Canada. The second consolation is that the Change Product Rule does
not apply to repairs and the issuance of an RDC.
long and the short of it is that the Change Product Rule is not
going to affect 90% of the day to day design change modifications