As the MD-80 was not in effect a new aircraft, it continues to be operated under an amendment to the original DC-9 FAA aircraft type certificate (a similar case to the later MD-90 and Boeing 717 aircraft).
Xa que o MD-80 non era de feito un avión novo, continúa sendo operado baixo unha modificación do certificado da FAA do orixinal DC-9 (un caso semellante ocorreu cos posteriores MD-90 e Boeing 717).