Who pays for the compliance with Airworthiness Directives (AD)? Airworthiness Directives (ADs) are legally enforceable regulations issued by the FAA in accordance with 14 CFR part 39 to correct an unsafe condition in a product. 


Hence when an AD is issued, owner must comply with the AD within the stated time period in order to remain airworthy. This compliance ,of course, come with some cost. Who pay for this cost of compliance? Owner of the plane? Manufacturer? Or they somehow share the cost?
It depends on the agreements between the operator/owner of the aircraft on one side and the manufacturer of the aircraft and its suppliers on the other side. 

Often there will be some form of compensation involved if an AD is issued when that AD is addressing non-compliance with regulations / standard in effect when the aircraft was produced. Normally there is some time limited warranty covering the costs of ADs at least partially.