14 CFR § 121.105
Servicing and maintenance facilities
July 13, 2020
Each certificate holder conducting domestic or flag operations must show that competent personnel and adequate facilities and equipment (including spare parts, supplies, and materials) are available at such points along the certificate holder's route as are necessary for the proper servicing, maintenance, and preventive maintenance of airplanes and auxiliary equipment.
[Doc. No. 28154, 61 FR 2610, Jan. 26, 1996]