I am involved in a program where the aircraft (B737) will undergo a major modification taking approximately 2 years which will ultimately result in a new type certificate being issued under a new authority. (Foreign) My question is do you continue with the continuing airworthiness requirements of the current document set i.e. MPD and other such manuals published as part of the current type certificate (A16WE) issued by the FAA until such time that the modification is released and new type certificate issued or does the design organization embodying the modification take control of all continuing airworthiness documentation and decide what happens and when?

My thinking is, irrespective of the aircraft eventually becoming a new type it has history and it has a current type certificate therefore my expectation would be you should continue to manage the current continuing airworthiness requirements associated with its current type certificate requirements. Only once the modification is completed does the new document set become applicable because only then would the new type certificate come into effect.

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    $\begingroup$ In case it is relevant: could you add in which country the modification is done or at which authority the new type certification will be applied for? $\endgroup$
    – Bianfable
    Commented Aug 26, 2021 at 12:36
  • $\begingroup$ I would expect it depends on what is being modified. The expectation would be that parts not being modified and subject to CAR would have to be compliant with CAR under the new TC - through either routine action or a catchup action prior to return to service. The parts being modified would need to be assessed and new CAR submitted as part of the application for the new TC. Sit down with the cert authority and make a plan. They make the rules and you have to show compliance. $\endgroup$
    – Gerry
    Commented Aug 26, 2021 at 13:19
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    $\begingroup$ I'm in the US, "foreign" means "not in the US". However, if I was British, "foreign" means "not in England". "Foreign" doesn't really mean much... $\endgroup$
    – FreeMan
    Commented Aug 26, 2021 at 18:06

1 Answer 1


Assuming you are in the US or a country with regs like the FAR's, this is no different than using type certified components on an aircraft with an experimental airworthiness certificate. In that case you are still required to keep up with AD's and SB's for those components. The minute you start modifying the airframe it is no longer compliant with the type certificate or former airworthiness certificate and you now have something that can only be flown under an experimental certificate of some kind. So for those TC'd components you intend to continue using on the aircraft after you finish modifications and get a new TC for the aircraft as a whole, you had better keep up with all the requirements, otherwise you'll have a steep climb catching up at the end of the game getting the airworthiness certificate when all is said and done. Whomever is the DAR is going to want to see all that before you are given a signoff.


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