An uncontrolled decompression is an undesired drop in the pressure of a sealed system, such as a pressurised aircraft cabin or hyperbaric chamber, that typically results from human error, structural failure, or impact, causing the pressurised vessel to vent into its surroundings or fail to pressurize at all.
Cabin pressurization is a process in which conditioned air is pumped into the cabin of an aircraft or spacecraft in order to create a safe and comfortable environment for humans flying at high altitudes. For aircraft, this air is usually bled off from the gas turbine engines at the compressor stage, and for spacecraft, it is carried in high-pressure, often cryogenic, tanks. The air is cooled, humidified, and mixed with recirculated air by one or more environmental control systems before it is distributed to the cabin.
United Airlines Flight 811 was a regularly scheduled airline flight from Los Angeles to Sydney, with intermediate stops at Honolulu and Auckland. On February 24, 1989, the Boeing 747-122 serving the flight experienced a cargo-door failure in flight shortly after leaving Honolulu. The resulting explosive decompression blew out several rows of seats, killing nine passengers. The aircraft returned to Honolulu and landed with no further incident.
An emergency landing is a premature landing made by an aircraft in response to an emergency involving an imminent or ongoing threat to the safety and operation of the aircraft, or involving a sudden need for a passenger or crew on board to terminate the flight. It typically involves a forced diversion to the nearest or most suitable airport or airbase, or an off airport landing or ditching if the flight cannot reach an airfield. Flights under air traffic control will be given priority over all other aircraft operations upon the declaration of the emergency.
Southwest Airlines Flight 1455 was a scheduled passenger flight from McCarran International Airport, Las Vegas, Nevada, to Burbank-Glendale-Pasadena Airport, Burbank, California, that overran the runway during landing on March 5, 2000. The aircraft, a Boeing 737-3T5, registration N668SW, came to rest on a city street adjacent to a gas station. The National Transportation Safety Board found that the incident was due to the pilots attempting to land with excessive speed. They also found that the air traffic controller placed them in a position from which their only option was a go around. Two of the passengers were seriously injured, and there were many minor injuries. As a result of the incident, the airport installed an Engineered Materials Arrestor System (EMAS) at the east end of the incident runway. The aircraft was written off, making the incident the 10th hull loss of a Boeing 737-300. This was the first major accident in the airline's 29-year history.
Adam Air Flight 172 was a scheduled domestic passenger flight from Soekarno–Hatta International Airport to Juanda Airport, Surabaya. On 21 February 2007, the Boeing 737-300 operating the flight made a hard landing at Surabaya and suffered fuselage cracking in the middle of the passenger section. All six of Adam Air's remaining 737s were immediately grounded, and five of them were back in regular service later that year. This incident caused further concerns regarding the safety of flights operated by Adam Air, which had received much criticism after the 1 January 2007 crash of Flight 574.
China Airlines Flight 120 was a regularly scheduled flight from Taiwan Taoyuan International Airport in Taoyuan County, Taiwan to Naha Airport in Okinawa, Japan. On August 20, 2007, the Boeing 737-800 aircraft operating the flight caught fire and exploded after landing and taxiing to the gate area at Naha Airport. Four people—three from the aircraft and one ground crew—sustained injuries in the accident. The fire had been caused by a loose bolt puncturing a fuel tank.
Philippine Airlines Flight 143 (PR143) was a domestic flight from the Manila Ninoy Aquino Airport, Manila, Philippines to Mandurriao Airport, Iloilo City. On May 11, 1990, at Manila Ninoy Aquino International Airport the Boeing 737-300 assigned to the route suffered an explosion in the central fuel tank and was consumed by fire in as little as four minutes. This accident marked the first Hull Loss of a 737-300.
The Boeing 737 Next Generation, commonly abbreviated as 737NG, or 737 Next Gen, is a narrow-body aircraft powered by two jet engines and produced by Boeing Commercial Airplanes. Launched in 1993 as the third generation derivative of the Boeing 737, it has been produced since 1997 and is an upgrade of the 737 Classic (−300/-400/-500) series.
Qantas Flight 30, on 25 July 2008, a Boeing 747-438 operated by Qantas, construction number 25067, registration VH-OJK, was a scheduled flight from London Heathrow to Melbourne with a stopover in Hong Kong. The flight was interrupted on the Hong Kong leg by an exploding oxygen tank that ruptured the fuselage just forward of the starboard wing root. 53-year-old Captain John Bartels and his co-pilots, Bernd Werninghaus and Paul Tabac, made an emergency descent to a breathable altitude of about 10,000 feet and diverted to Ninoy Aquino International Airport, Metro Manila, Philippines. There were no injuries.
On 22 December 2009, an American Airlines Boeing 737-800, operating American Airlines Flight 331 and carrying 148 passengers and six crew, overran runway 12 on landing at Kingston in poor weather. The plane continued on the ground outside the airport perimeter and broke apart on the beach, causing injuries.
Southwest Airlines Flight 812 was a Boeing 737-300 passenger jet that on April 1, 2011, suffered rapid depressurization while cruising at 34,000 ft (10,000 m) near Yuma, Arizona, leading to an emergency landing at Yuma International Airport. Two of the 123 people on board suffered minor injuries. The aircraft was operating Southwest Airlines' domestic scheduled service from Phoenix, Arizona, to Sacramento, California.
Northwest Airlines Flight 85 was a scheduled international passenger flight from Detroit Metropolitan Wayne County Airport in the United States to Narita International Airport in Japan. On October 9, 2002, while over the Bering Sea, the Boeing 747-400 experienced a lower rudder hardover event, which occurs when an aircraft's rudder deflects to its travel limit without crew input. The 747's hardover gave full left lower rudder, requiring the pilots to use full right upper rudder and right aileron to maintain attitude and course.
Delta Air Lines Flight 1288 was a regularly scheduled flight from Pensacola, Florida to Atlanta, Georgia. On July 6, 1996, the aircraft serving the flight, a McDonnell Douglas MD-88, was on takeoff roll from Runway 17 at Pensacola when it experienced an uncontained, catastrophic turbine engine failure that caused debris from the front compressor hub of the left engine to penetrate the left aft fuselage. The cause of the engine failure was found to have been a fault in the manufacture of the fan. The failure of the airline to spot the resulting crack in the blade was a contributing factor.
Southwest Airlines Flight 3472 was a regularly scheduled passenger flight operating from New Orleans International Airport in New Orleans, Louisiana to Orlando International Airport in Orlando, Florida. On August 27, 2016, the Boeing 737-7H4, with 99 passengers and five crew, 12 minutes after departure from New Orleans, was climbing through 31,000 feet and heading east over the Gulf of Mexico when the aircraft's number one CFM International CFM56-7 engine suffered an engine failure. A fan blade in the engine broke due to a fatigue crack. The separated portion of the blade rotated within the engine, moving forward, striking the engine inlet. Debris from the damaged engine inlet punctured the left side of the fuselage causing a loss of cabin pressure and damaged the wing and empennage. Oxygen masks were deployed to passengers while the crew initiated an emergency descent to 10,000 feet. The aircraft then diverted to Pensacola International Airport for a safe landing about 20 minutes later without further incident. While the aircraft sustained substantial damage, there were no injuries.
On February 13, 2018, around noon local time, a Boeing 777-222 airplane, operating as United Airlines Flight 1175 (UA1175), experienced an in-flight separation of a fan blade in the No. 2 (right) engine while over the Pacific Ocean en route to the Daniel K. Inouye International Airport (HNL), Honolulu, Hawaii. During level cruise flight shortly before beginning a descent from flight level 360, and about 120 miles from HNL, the flight crew heard a loud bang, followed by a violent shaking of the airplane, followed by warnings of a compressor stall. The flight crew shut down the failed engine, declared an emergency, and began a drift-down descent, proceeding direct to HNL where they made a single-engine landing without further incident at 12:37 local time. There were no reported injuries to the 374 passengers and crew on board and the airplane damage was classified as minor under National Transportation Safety Board (NTSB) criteria.
Southwest Airlines Flight 1380 was a Boeing 737-700 that experienced a contained engine failure in the left CFM56-7B engine after departing from New York–LaGuardia Airport en route to Dallas Love Field on April 17, 2018. The engine cowl was broken in the failure and cowl fragments damaged the fuselage, causing explosive depressurization of the aircraft after damaging a cabin window. Other fragments caused damage to the wing. The crew carried out an emergency descent and diverted to Philadelphia International Airport. One passenger was partially ejected from the aircraft and sustained fatal injuries, while eight other passengers sustained minor injuries. The aircraft was substantially damaged.
On February 20, 2021, United Airlines Flight 328 (UA328/UAL328), a scheduled U.S. domestic passenger flight from Denver to Honolulu, suffered a contained engine failure four minutes after takeoff from Denver International Airport (DEN). Parts departing from the engine cowling of the Boeing 777-222 aircraft resulted in a debris field at least 1 mile (1.6 km) long over suburban residential areas of Broomfield, Colorado. Falling debris was recorded by eyewitnesses using smartphone cameras and a dash cam. Debris fell through the roof of a private home and significantly damaged a parked vehicle.
