AMC M.A.305(e)(3) Aircraft continuing airworthiness record system
CAA ORS9 Decision No. 1
(a) An CAA Form 1 and detailed maintenance records are not required to be kept to support every installation/removal shown in the in-service history records.
(b) Conservative methods to manage missing historical periods are acceptable to establish the current status of the life-limited part. In case of use of a conservative method, the supporting documents should be endorsed. Recommendations from the design approval holder on the procedures to record or reconstruct the in-service history should be considered.