How to obtain an airworthiness certificate for a helicopter that lost it.

[educob]

Hi.

I have seen a helicopter that lost the airworthiness certificate cause they don't have the logs.

What would I have to do to get a new airworthiness certificate?

Thanks.

[Disguise Delimit]

Be very suspicious about "lost log books", as you cannot verify the maintenance history of the aircraft. No evidence that it has not been crashed or damaged or even serviced.  If you are talking about the homebuilt Rotorway Exec in your other post, then turn 180 degrees and run as fast as you can.