Question: Who built the type of jet that made an emergency landing in Detroit on April 4, 1979?

Context paragraphs:
Emergency landing: An emergency landing is a priortised landing made by an aircraft in response to an emergency which contains an imminent or on-going threat to the safety and operation of the aircraft or involves a sudden need for a passenger or crew on board to be on land such as a medical emergency.

TWA Flight 841 (1979): TWA Flight 841 was a domestic, scheduled passenger flight from John F. Kennedy International Airport in New York City, en route to Minneapolis-Saint Paul International Airport in Minneapolis, Minnesota.  On April 4, 1979, at or around 9:48 p.m. Eastern Standard Time (01:48 UTC), while flying over Saginaw, Michigan, the Boeing 727-31 airliner began a sharp, uncommanded roll to the right, and subsequently went into a spiral dive.  The pilots were able to regain control of the aircraft and made a successful emergency landing at Detroit Metropolitan Airport.

Forced landing: A forced landing is a landing by an aircraft made under factors outside the pilot's control, such as the failure of engines, systems, components or weather which makes continued flight impossible.  For a full description of these, see article on "emergency landing".  However the term also means a landing that has been forced by interception.

Crash Landing (disambiguation): Crash landing, or emergency landing, is an unplanned landing made by an aircraft.

Advance Airlines Flight 4210: Advance Airlines Flight DR4210 was a scheduled passenger flight which crashed at Sydney Airport on 21 February 1980, killing all 13 people on board the Advance Airlines Beech Beechcraft King Air 200.  After taking off on runway 25 for a scheduled flight the aircraft's left (port) engine failed and the pilot requested an emergency landing on runway 34.  The plane crashed into the sea wall while attempting the emergency landing.  The accident caused the greatest number of fatalities in a civil aircraft crash in Australia since MacRobertson Miller Airlines Flight 1750, a Vickers Viscount that crashed near Port Hedland in Western Australia on 31 December 1968 killing all 26 on board.

Marden Airfield: Marden Airfield was an airfield in Marden, Kent, United Kingdom.  It was operation from 1917 to 1935.  Initially a Royal Flying Corps airfield during the First World War it was used post-war as an Emergency Landing Strip, RAF Marden by the Royal Air Force.  It was also known as Pagehurst Emergency Landing Ground.  Later serving as a civil Emergency Landing Ground, the airfield closed in 1935.  The site housed a Royal Air Force transmitter station during the Second World War.

Emergency Landing (1941 film): Emergency Landing (a.k.a. Robot Pilot) is a 1941 American aviation spy-fi romantic screwball comedy film directed by William Beaudine.  The film stars Forrest Tucker in his second film and in his first leading role with co-stars Carol Hughes and Evelyn Brent.  "Emergency Landing" features lots of mismatched stock footage of various types of aircraft.

Boeing 727: The Boeing 727 is a midsized, narrow-body three-engined jet aircraft built by Boeing Commercial Airplanes from the early 1960s to 1984.  It can carry 149 to 189 passengers and later models can fly up to 2700 nmi nonstop.  Intended for short and medium-length flights, the 727 can use relatively short runways at smaller airports.  It has three Pratt & Whitney JT8D engines below the T-tail, one on each side of the rear fuselage with a center engine that connects through an S-duct to an inlet at the base of the fin.  The 727 is Boeing's only trijet aircraft.

LOT Polish Airlines Flight 16: LOT Polish Airlines Flight 16 was a passenger flight which made an emergency landing at Warsaw Chopin Airport, Poland, on 1 November 2011 after its landing gear failed to extend.  All 231 aboard survived without any significant injuries.  The aircraft involved, a Boeing 767-300ER, was operating as LOT Polish Airlines' scheduled international service from Newark Liberty International Airport, New Jersey, USA, to Warsaw.  The preliminary report found that a hydraulic leak occurred shortly after takeoff, which resulted in a loss of all the hydraulic fluid that powered the primary landing gear system.

Fuel dumping: Fuel dumping (or a fuel jettison) is a procedure used by aircraft in certain emergency situations before a return to the airport shortly after takeoff, or before landing short of its intended destination (emergency landing) to reduce the aircraft's weight.

Supporting paragraphs: TWA Flight 841 (1979) Boeing 727
Answer: Boeing Commercial Airplanes