§ 22.135 Instruments and equipment.
(a) The aircraft must have all instruments and equipment necessary for safe flight, to include those instruments necessary for systems control and management.
(b) The aircraft must include all instruments and equipment required for the kinds of operations for which it is authorized.
(c) The aircraft's, instruments, equipment, and systems must perform their intended functions under all operating conditions specified in the pilot's operating handbook. Likely failure or malfunction of equipment or a system must not cause loss of control of the aircraft. Equipment and systems must be considered separately and in relation to each other.