California Code, Code of Civil Procedure - CCP § 1208.62

That portion of such lien in excess of two hundred fifty dollars ($250) for work or services rendered or performed at the request of any person other than the holder of the legal title is invalid, unless prior to commencing such work or service the person claiming the lien gives actual notice to the legal owner and the mortgagee, if any, of the aircraft, and the written consent of the legal owner and the mortgagee of the aircraft is obtained before such work or services are performed. For the purposes of this chapter the person named in the federal aircraft registration certificate issued by the Administrator of Civil Aeronautics shall be deemed to be the legal owner.