The aft pressure bulkhead or rear pressure bulkhead is the rear component of the pressure seal in all aircraft that cruise in a tropopause zone in the Earth's atmosphere. [1] It helps maintain pressure when stratocruising and protects the aircraft from bursting due to the higher internal pressure.
Aft pressure bulkheads can either be curved, which reduces the amount of metal needed at the cost of reducing the usable space in the airliner, or flat, which gives more internal space but also more weight. [2] [3] Patents have been filed that propose deliberately creating cavities within the rear bulkhead with the purpose of providing more usable cabin space. [4] On several airliners, production of the rear pressure bulkhead has been outsourced to third party manufacturers. [5] [6] [7] While typically being a time-consuming and somewhat uncommon process, an aircraft's aft pressure bulkhead can be wholly replaced. [8]
During the twenty-first century, various parties became increasingly interested in developing aft pressure bulkheads composed from composite materials, seeking benefits such as lower manufacturing costs, easier sealing, elimination of corrosion risk, along with weight and part count reductions. [9] During the early 2000s, Airbus Group developed the largest manufactured resin film infusion structure then in production to function as the aft pressure bulkhead for their double-decker A380 airliner. [10] the German aerospace supplier Premium AEROTEC, which successfully manufactured the world's first thermoplastic-based rear pressure bulkhead during the 2010s; according to the firm, the new unit had reportedly resulted in a 75% reduction in processing and assembly time as well as a noticeable weight saving over traditional aluminium counterparts. [11]
Multiple instances of damage to the aft pressure bulkhead have occurred; while a few cases have led to serious failures leading to aircraft losses, others have proven to be survivable. [12] [13] [14] Aviation certifying authorities have often mandated inspections of an aircraft's aft pressure bulkhead in the interest of safety. [15] [16] Various techniques have been devised to determine the integrity of the rear pressure bulkhead; these have been used not only to inspect in-service examples but also in the design process, helping to design efficient bulkheads that possess sufficient strength to ensure a safe operational life. [17]
In 1971, British European Airways Flight 706 crashed in Belgium, killing all 63 on board; the cause was determined to be corrosion of the rear pressure bulkhead by fluid contamination, perhaps from the lavatory. The corrosion was not detectable by the inspection techniques at the time.
In 1985, Japan Airlines Flight 123 crashed after a catastrophic failure of the aft pressure bulkhead. [18] The failure occurred due to faulty repair of the bulkhead after a tailstrike seven years earlier, when a single repair patch plate was incorrectly cut in two "to make it fit". Failure of the bulkhead damaged hydraulic pipes passing through. Boeing later calculated that the incorrect installation would be expected to fail after approximately 10,000 pressurizations; the repaired aircraft accomplished 12,318 successful flights before the crash. [19] [20]
During 2013, National Airlines Flight 102 crashed after loose freight on the main deck is believed to have penetrated the aft pressure bulkhead and caused damage to control systems in the vicinity of the bulkhead. [21]
The Boeing 767 is an American wide-body aircraft developed and manufactured by Boeing Commercial Airplanes. The aircraft was launched as the 7X7 program on July 14, 1978, the prototype first flew on September 26, 1981, and it was certified on July 30, 1982. The initial 767-200 variant entered service on September 8, 1982, with United Airlines, and the extended-range 767-200ER in 1984. It was stretched into the 767-300 in October 1986, followed by the extended-range 767-300ER in 1988, the most popular variant. The 767-300F, a production freighter version, debuted in October 1995. It was stretched again into the 767-400ER from September 2000.
The Boeing 747 is a large, long-range wide-body airliner designed and manufactured by Boeing Commercial Airplanes in the United States between 1968 and 2023. After introducing the 707 in October 1958, Pan Am wanted a jet 2+1⁄2 times its size, to reduce its seat cost by 30%. In 1965, Joe Sutter left the 737 development program to design the 747. In April 1966, Pan Am ordered 25 Boeing 747-100 aircraft, and in late 1966, Pratt & Whitney agreed to develop the JT9D engine, a high-bypass turbofan. On September 30, 1968, the first 747 was rolled out of the custom-built Everett Plant, the world's largest building by volume. The 747's first flight took place on February 9, 1969, and the 747 was certified in December of that year. It entered service with Pan Am on January 22, 1970. The 747 was the first airplane called a "Jumbo Jet" as the first wide-body airliner.
The Boeing 777, commonly referred to as the Triple Seven, is an American long-range wide-body airliner developed and manufactured by Boeing Commercial Airplanes. The 777 is the world's largest twinjet and the most-built wide-body airliner. The jetliner was designed to bridge the gap between Boeing's other wide body airplanes, the twin-engined 767 and quad-engined 747, and to replace aging DC-10 and L-1011 trijets. Developed in consultation with eight major airlines, the 777 program was launched in October 1990, with an order from United Airlines. The prototype was rolled out in April 1994, and first flew in June. The 777 entered service with the launch operator United Airlines in June 1995. Longer-range variants were launched in 2000, and first delivered in 2004.
The Boeing 787 Dreamliner is an American wide-body airliner developed and manufactured by Boeing Commercial Airplanes. After dropping its unconventional Sonic Cruiser project, Boeing announced the conventional 7E7 on January 29, 2003, which focused largely on efficiency. The program was launched on April 26, 2004, with an order for 50 aircraft from All Nippon Airways (ANA), targeting a 2008 introduction. On July 8, 2007, a prototype 787 without major operating systems was rolled out; subsequently the aircraft experienced multiple delays, until its maiden flight on December 15, 2009. Type certification was received in August 2011, and the first 787-8 was delivered in September 2011 before entering commercial service on October 26, 2011, with ANA.
A stick shaker is a mechanical device designed to rapidly and noisily vibrate the control yoke of an aircraft, warning the flight crew that an imminent aerodynamic stall has been detected. It is typically present on the majority of large civil jet aircraft, as well as most large military planes.
China Airlines Flight 611 was a regularly scheduled passenger flight from Chiang Kai-shek International Airport in Taiwan to Hong Kong International Airport in Hong Kong.
Japan Air Lines Flight 123 was a scheduled domestic passenger flight from Tokyo to Osaka, Japan. On August 12, 1985, the Boeing 747 flying the route suffered a severe structural failure and decompression 12 minutes into the flight. After flying under minimal control for a further 32 minutes, the 747 crashed in the area of Mount Takamagahara, 100 kilometres from Tokyo.
The mechanical structure of an aircraft is known as the airframe. This structure is typically considered to include the fuselage, undercarriage, empennage and wings, and excludes the propulsion system.
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 without further incident.
The Boeing 747SP is a shortened version of the Boeing 747 wide-body airliner, designed for a longer range. It is the highest flying subsonic passenger airliner, with a service ceiling of 45,100 feet . Boeing needed a smaller aircraft to compete with the McDonnell Douglas DC-10 and Lockheed L-1011 TriStar tri-jet wide-bodies, introduced in 1971/1972. Pan Am requested a 747-100 derivative to fly between New York and the Middle East, a request also shared by Iran Air, and the first order came from Pan Am in 1973.
The Japan Airlines Safety Promotion Center is a museum and educational center operated by Japan Airlines to promote airline safety. It is located on the grounds of Tokyo International Airport in Ota, Tokyo, Japan. The center estimates that its facility is within two minutes walking distance from the Tokyo Monorail Shin Seibijō Station.
As of July 2020, a total of 60 Boeing 747 aircraft, or just under 4% of the total number of 747s built, first flown commercially in 1970, have been involved in accidents and incidents resulting in a hull loss, meaning that the aircraft was either destroyed or damaged beyond economical repair. Of the 60 Boeing 747 aircraft losses, 32 resulted in no loss of life; in one, a hostage was murdered; and in one, a terrorist died. Some of the aircraft that were declared damaged beyond economical repair were older 747s that sustained relatively minor damage. Had these planes been newer, repairing them might have been economically viable, although with the 747's increasing obsolescence, this is becoming less common. Some 747s have been involved in accidents resulting in the highest death toll of any civil aviation accident, the highest death toll of any single airplane accident, and the highest death toll of a midair collision. As with most airliner accidents, the root of cause(s) in these incidents involved a confluence of multiple factors that rarely could be ascribed to flaws with the 747's design or its flying characteristics.
Zonal Safety Analysis (ZSA) is one of three analytical methods which, taken together, form a Common Cause Analysis (CCA) in aircraft safety engineering under SAE ARP4761. The other two methods are Particular Risks Analysis (PRA) and Common Mode Analysis (CMA). Aircraft system safety requires the independence of failure conditions for multiple systems. Independent failures, represented by an AND gate in a fault tree analysis, have a low probability of occurring in the same flight. Common causes result in the loss of independence, which dramatically increases probability of failure. CCA and ZSA are used to find and eliminate or mitigate common causes for multiple failures.
Premium AEROTEC is a German aerospace manufacturing business, headquartered in Augsburg in Germany. It is a subsidiary of Airbus.
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.
British European Airways Flight 706 (BE706/BEA706) was a scheduled international passenger flight from United Kingdom to Salzburg, Austria. On 2 October 1971, whilst en route at 19,000 feet (5,791 m), the Vickers Vanguard suffered a failure with its rear cabin pressure bulkhead. The resulting depressurisation of the tail section caused the surfaces of the tailplanes to separate. The aircraft entered an uncontrollable dive and crashed near Aarsele, Belgium, killing all 63 passengers and crew on impact. A piece of debris from the aircraft struck a passing car, causing minor injuries to one of its occupants.
The Boeing 777X is the latest series of the long-range, wide-body, twin-engine jetliners in the Boeing 777 family from Boeing Commercial Airplanes. The 777X features new GE9X engines, new composite wings with folding wingtips, greater cabin width and seating capacity, and technologies from the Boeing 787. The 777X was launched in November 2013 with two variants: the 777-8 and the 777-9. The 777-8 provides seating for 384 passengers and has a range of 8,745 nautical miles [nmi] while the 777-9 has seating for 426 passengers and a range of over 7,285 nmi.
A four-engined jet, sometimes called a quadjet, is a jet aircraft powered by four engines. The presence of four engines offers increased power, allowing such aircraft to be used as airliners, freighters, and military aircraft. Many of the first purpose-built jet airliners had four engines, among which stands the De Havilland Comet, the world's first commercial jetliner. In the decades following their introduction, their use has gradually declined due to a variety of factors, including the approval of twin-engine jets to fly farther from diversion airports as reliability increased, and an increased emphasis on fuel efficiency.
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 from San Francisco International Airport (SFO) 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.
