14 CFR § 21.127 - Tests: aircraft.
(a) Each person manufacturing aircraft under a type certificate must establish an approved production flight test procedure and flight check-off form, and in accordance with that form, flight test each aircraft produced.
(b) Each production flight test procedure must include the following:
(2) An operational check of each part or system operated by the crew while in flight to establish that, during flight, instrument readings are within normal range.
(3) A determination that all instruments are properly marked, and that all placards and required flight manuals are installed after flight test.
(4) A check of the operational characteristics of the aircraft on the ground.