2011‑NM‑132‑AD The Boeing Company Model DC-9-10, DC‑9-20, DC‑9‑30, DC‑9‑40, and DC‑9‑50 series airplanes; and Model DC‑9‑81 (MD‑81), DC‑9‑82 (MD‑82), DC‑9‑83 (MD‑83), DC‑9‑87 (MD‑87), MD-88, and MD‑90-30 airplanes