ARRANGEMENTS Natural or legal persons that hold or that have applied for a type certificate (TC), a supplemental type certificate (STC), a major repair design approval, a permit to fly, a certificate of airworthiness, a restricted certificate of airworthiness, a noise certificate or a restricted noise certificate, that have declared design compliance, that have declared their design or production capability or that produce aircraft, engines, propellers or parts under Subpart R are required to allow the competent authority to make investigations that include the complete organisation including its partners, subcontractors and suppliers, whether they are in the State of the natural or legal person or not. The investigations may include audits, enquiries, questions, discussions and explanations, monitoring, witnessing, inspections, checks, flight and ground tests, and inspections of completed products or parts that are either designed or produced. In order to maintain its confidence in the standards achieved by the natural or legal person, the competent authority may conduct an investigation of a sample product or part and of its associated records, reports and certifications/declarations. The arrangements are required to enable the natural or legal person to assist the competent authority and cooperate with it in conducting the investigation during the initial assessment and for the subsequent surveillance. ‘Cooperation in performing investigations’ means the competent authority has been granted full and free access to the facilities and to any information relevant to demonstrating compliance with the Part 21 Light requirements, and has provided assistance as necessary. ‘Assistance to the competent authority’ includes all the appropriate means regarding the facilities of the natural or legal person to allow the competent authority to conduct the investigation, such as meeting rooms, offices, support personnel, records, documentation, computer data, and communication facilities, all properly and promptly made available as necessary. The competent authority seeks to have a good working relationship with the natural or legal person, and suitable liaison staff are required to be nominated to facilitate this, including one or more suitable representative(s) to accompany competent authority staff during visits, not only at the natural or legal person’s own facilities, but also with subcontractors, partners or suppliers.