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 Air Lines 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 747 is a long-range wide-body airliner designed and manufactured by Boeing Commercial Airplanes in the United States between 1968 and 2023. After the introduction of 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 aircraft rolled out in April 1994, and first flew in June of that year. 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, it 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.
Aloha Airlines Flight 243 was a scheduled Aloha Airlines flight between Hilo and Honolulu in Hawaii. On April 28, 1988, a Boeing 737-297 serving the flight suffered extensive damage after an explosive decompression in flight, caused by part of the fuselage breaking due to poor maintenance and metal fatigue. The plane was able to land safely at Kahului Airport on Maui. The one fatality, flight attendant Clarabelle "C.B." Lansing, was ejected from the airplane. Sixty-five passengers and crew were injured. The substantial damage inflicted by the decompression, the loss of one cabin crew member, and the safe landing of the aircraft established the accident as a significant event in the history of aviation, with far-reaching effects on aviation safety policies and procedures.
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 international 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.
In aviation, a tailstrike or tail strike occurs when the tail or empennage of an aircraft strikes the ground or other stationary object. This can happen with a fixed-wing aircraft with tricycle undercarriage, in both takeoff where the pilot rotates the nose up too rapidly, or in landing where the pilot raises the nose too sharply during final approach, often in attempting to land too near the runway threshold. It can also happen during helicopter operations close to the ground, when the tail inadvertently strikes an obstacle.
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 (13,700 m). 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 January 2025, a total of 64 Boeing 747 aircraft, or just above 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 64 Boeing 747 aircraft losses, 32 resulted in no loss of life; in one, a hostage was murdered; and in one, a terrorist died.
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 122 people on board suffered minor injuries. The aircraft was operating Southwest Airlines' domestic scheduled service from Phoenix, Arizona, to Sacramento, California.
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 changes for 777X include General Electric GE9X engines, 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 395 passengers and has a range of 8,745 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 and redundancy, 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 to the Daniel K. Inouye International Airport, 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 378 passengers and crew on board and the airplane damage was classified as minor under National Transportation Safety Board (NTSB) criteria.
