text:
Talk:Absolute value

Absolute number listed at Redirects for discussion
An editor has asked for a discussion to address the redirect Absolute number. Please participate in the redirect discussion if you wish to do so. — Arthur Rubin (talk) 10:43, 19 May 2019 (UTC)

Short description
The purpose of a short description is to aid disambiguation, not to be a comprehensive mini-definition of the subject. Sometimes mini-definitions can work, but in this case it'd require going over the 40-character target (the previous description was 60 characters). {{u| Sdkb  }}  talk 19:49, 14 May 2021 (UTC)
 * "Concept" is even shorter and is almost as useful as "Mathematics concept". Moreover, "Mathematics concept" is gramatically dubious and, in any case, ambiguous: it may mean "concept of mathematics" or "concept in mathematics", but certainly not "concept used in mathematics" which seems to be the intended meaning. Also, the limit of 40 characters is a recommendation, not a policy.
 * This being said the current formulation is not very good, not because its number of characters, but because it is too cumbersome. I'll try for a better formulation. D.Lazard (talk) 20:35, 14 May 2021 (UTC)
 * Another possibility might be "distance of a number from zero" (30 characters). —David Eppstein (talk) 20:56, 14 May 2021 (UTC)
 * I like that a lot. {{u| Sdkb  }}  talk 21:09, 14 May 2021 (UTC)
 * Me too. Paul August ☎ 00:58, 15 May 2021 (UTC)
 * Before reading David's suggestion, I have changed the sd into "Magnitude of a possibly negative number" (39 character). IMO, the two versions are acceptable. I have thought to a version using "distance", but I have rejected it because this use of "distance" may be confusing for a non-mathematician. Another reason of my choice is that it emphasizes that the absolute value makes sense only if non-positive numbers are considered. I'll not be bothered if there is a consensus for David's version. D.Lazard (talk) 08:50, 15 May 2021 (UTC)

Absolute value as a maximum
I have just seen the equation $$|x| = \max(x, -x)$$ and I am absolutely baffled that I had not come across this until now! Surely this should be included somewhere in the article, as it is much more compact than the piecewise definition – indeed it "piggybacks" off of the piecewise definition of the maximum, $$\max(a, b) = \begin{cases} a, & a \geq b \\ b, & a < b \end{cases}$$, so that one only has to define one of $$|\ |$$ and $$\max(\, )$$ by a piecewise formula, not both. The fact that this formula is not in the article suggests to me that many other people also have not seen this property (of course it's obvious once you have seen it, but without seeing it most people wouldn't think of it). Joel Brennan (talk) 22:26, 18 April 2022 (UTC)

|x| <= a doesn't imply -a<= x <= a
From -a <= x <= a, we would have x = a and x = -a, a contradiction. Maybe the intention was to write:

 * x| < a iff -a < x < a.

I never saw a book that explains this equivalences. I mean, though intuitive, what is the logical justification why we get the logical "and" in a situation and the logical "or" in another? For example:

 * x| = a iff x = a or x = -a

 * x| < a iff x -a

 * x|> a iff x > a or x > -a

The explanation I gave to myself is that the definition of abs is equivalent to:

(x>=0 and |x| := x) or (x<0 and |x| := - x).

For example |x| < a iff

(x >= 0 and x < a) or ( x < 0 and -x < a).

And then it's just interval calculations and distributions of logical operations. Sr cricri (talk) 18:32, 2 April 2023 (UTC)

 * Perhaps rather than trying to convince us by drawn-out explanations you could provide an explicit example of two numbers $$x$$ and $$a$$ for which $$|x|\le a$$ but not $$-a\le x\le a$$. If you could do that, it would make for a more convincing argument. —David Eppstein (talk) 18:36, 2 April 2023 (UTC)
 * Oh, I see now, you are right David. I didn't see that |x| <= a is x < a or x = a. Maybe it is better to delete this topic discussion. Sr cricri (talk) 18:56, 2 April 2023 (UTC)

Absolute Value = Modulus? Is this entirely accurate?
"In mathematics, the absolute value or modulus " - are these terms equal or does it depend on context?

This discussion came up in a stack overflow thread which referenced this article as evidence that absolute value = modulus. However, some additional reading suggests that these may not be entirely interchangeable terms, perhaps making this article a source of misinformation. It's been about 20 years since my last math class, so I'm hoping someone more familiar with this subject matter might be able to clarify this as it is causing discussion and confusion elsewhere:

https://stackoverflow.com/questions/664852/which-is-the-fastest-way-to-get-the-absolute-value-of-a-number

https://math.stackexchange.com/questions/472856/what-is-the-difference-between-modulus-absolute-value-and-modulo Oudent (talk) 05:36, 18 July 2023 (UTC)

 * This is going to depend on some specific source's precise definitions. As with most things of mathematics, conventions are not entirely standardized and vary a bit from country to country, year to year, source to source. Some sources surely treat these as interchangeable synonyms. Other sources might use "absolute value" for real numbers and "modulus" for complex numbers, vectors, matrices, or other kinds of quantities. This article seems fine though. –jacobolus (t) 06:14, 18 July 2023 (UTC)

n-fold derivative
My edit correcting the formula of the derivative was undone. The formula given currently is: $${d^n \over dx^n} f(\left\vert x \right\vert) = {x \over |x|} ({d^n \over dx^n} f(|x|))$$

which has the typographical mistake that the derivative of the function f(|x|) is conflated with the derivative of the function f that is since postcomposed with |x|. My remedy was to write it instead as:

$${d^n \over dx^n} f(\left\vert x \right\vert) = {x \over |x|}(f^{(n)}(|x|))$$

But if there is a dislike of Newton notation, one could write it as:

$${d^n \over dx^n} f(\left\vert x \right\vert) = {x \over |x|} ({d^n f \over dx^n} (|x|))$$

as well. Regardless the current formula is incorrect. Qsdd (talk) 14:08, 12 October 2023 (UTC)
 * The problem is that the two versions are wrong, since the right formula is The formula that follows is also wrong, and the sentence that introduces these two formula is nonsensical. Moreover, AFAIK, higher derivatives of the absolute value are rarely considered, and I am thus unable to provide reliable sources for these formulas.
 * For these reasons, I have removed the two formulas and their introduction. Feel free to provide the right formulas if you are able to provide a reliable source. D.Lazard (talk) 18:26, 12 October 2023 (UTC)

title: Talk:Absolute value


text:
Talk:Advanced Encryption Standard

Citation Needed for Optimization of Cipher
Where did the information in this section come from? 129.74.154.239 (talk)

Poorly referenced assertion that ChaCha is better.
In this diff, someone added the following content:

 * Where the CPU hardware does not support AES acceleration, ChaCha is an alternative cipher with better performance and without sacrificing security.

AES-128 broken to a complexity of 2^96
join the effort it's open! The main programmer who is doing this work, is limited to a 4 core Xeon 1275 with 3 active cores. We need people with fast boxes and a will to look at the code and improve it.

Supported by the following refs:

 * (Blog, unreliable source)
 * (The website of the maker of ChaCha is not going to be neutral w.r.t ChaCha)

This violates WP:UNDUE, especially since the references supporting this assertion are rather dubious. Blogs are not reliable sources, as per WP:BLOGS. The website of the designer of ChaCha is not a neutral nor reliable source, as per WP:NPOV and WP:SPS. Samboy (talk) 21:20, 29 January 2022 (UTC)

Neither of those references supports the claim in any way. —Naddy (talk) 10:24, 9 May 2024 (UTC)

license: Creative Commons - Attribution Share-Alike - https://creativecommons.org/licenses/by-sa/4.0/

title: Talk:Advanced Encryption Standard


text:
Adelaide of Italy

Adelaide of Italy (Adelheid; 931 – 16 December 999 AD), also called Adelaide of Burgundy, was Holy Roman Empress by marriage to Emperor Otto the Great. She was crowned with him by Pope John XII in Rome on 2 February 962. She was the first empress designated consors regni, denoting a "co-bearer of royalty" who shared power with her husband. She was essential as a model for future consorts regarding both status and political influence. She was regent of the Holy Roman Empire as the guardian of her grandson in 991–995.

Early life
Adelaide was born in Orbe Castle, Orbe, Kingdom of Upper Burgundy (now in modern-day Switzerland), to Rudolf II of Burgundy, a member of the Elder House of Welf, and Bertha of Swabia.

Adelaide was involved from the outset in the complicated fight to control not only Burgundy but also Lombardy. The battle between her father Rudolf II and Berengar I to control northern Italy ended with Berengar's death, enabling Rudolf to claim the throne.

Not happy with this, the inhabitants of Lombardy appealed to another ally, Hugh of Provence, who had long considered Rudolf an enemy. Although Hugh challenged Rudolf for the Burgundian throne, he only succeeded when Adelaide's father died in 937. So as to control Upper Burgundy, Hugh decided to marry his son Lothair II, the nominal King of Italy, to the 15-year-old Adelaide (in 947, before 27 June).

The marriage produced a daughter, Emma of Italy, born about 948. Emma became Queen of West Francia by marrying King Lothair of France.

Marriage and alliance with Otto I

The calendar of saints states that Lothair was poisoned on 22 November 950 in Turin by the holder of real power, his successor, Berengar II of Italy.

There were some suspicions amongst the people of Lombardy that Adelaide wanted to rule the kingdom by herself. Berengar attempted to thwart this and cement his political power by forcing her to marry his son Adalbert. Adelaide refused and fled, taking refuge in the castle of Como. However, she was quickly tracked down and was imprisoned for four months at Garda.

According to Adelaide's contemporary biographer, Odilo of Cluny, she managed to escape from captivity. After a time spent in the marshes nearby, she was rescued by a priest and taken to a "certain impregnable fortress," likely the fortified town of Canossa Castle near Reggio. She was able to send an emissary to the East Frankish king Otto I asking for his protection. Adelaide met Otto at the old Lombard capital of Pavia and they married on 23 September 951. Early in their marriage, Adelaide and Otto had two children, Henry and Bruno, both of whom died before reaching adulthood.

A few years later, in 953, Liudolf, Duke of Swabia, Otto's son by his first marriage, instigated a big revolt that was quelled by his father. As a consequence, Otto decided to dispossess Liudolf of his ducal title. This decision favoured the position of Adelaide and her descendants at court. Adelaide also managed to retain her entire territorial dowry.

After returning to Germany with his new wife, Otto cemented the Holy Roman Empire by defeating the Hungarian invaders at the Battle of Lechfeld on 10 August 955. He then extended the boundaries of East Francia beyond the Elbe River, defeating the Obotrites and other Slavs of the Elbe at the battle of Recknitz on 16 October 955. That same year, Adelaide gave birth to Otto II. In 955 or 956, she gave birth to a daughter who would become Matilda, Abbess of Quedlinburg.

Holy Roman Empress
Adelaide accompanied her husband on his second expedition to Italy to subdue the revolt of Berengar II and to protect Pope John XII. In Rome, Otto the Great was crowned Holy Roman Emperor on 2 February 962 by Pope John XII. Breaking new ground, Pope John XII also crowned Adelaide as Holy Roman Empress. In 960, a new ordo was created for her coronation and anointing, including prayers to biblical female figures, especially Esther. The ordo presents a theological and political concept that legitimizes the empress's status as a divinely ordained component of the earthly rule. In 966, Adelaide and the eleven-year-old Otto II, travelled again with Otto on his third expedition to Italy, where the Emperor restored the newly elected Pope John XIII to his throne (and executed some of the Roman rioters who had deposed him). Crucial to Otto's establishing legitimacy in his conquest of Italy and in bringing the imperial crown to the couple, was the support of Adelaide and her extensive network of relations. As heir to the Italian throne, Adelaide established for late Carolingian traditions the legitimate claim over Italy by the imperial throne.

Adelaide remained in Rome for six years while Otto ruled his kingdom from Italy. Otto II was crowned co-emperor in 967, then married the Byzantine princess Theophanu in April 972, resolving the conflict between the two empires in southern Italy and ensuring the imperial succession. Adelaide and her husband returned to Germany, where Otto I died in May 973, at the same Memleben palace where his father had died 37 years earlier.

After her coronation, which increased her power as she was now consors regni and able to receive people from the entire Empire, Adelaide's interventions in political decisions increased. According to Buchinger, "Between 962 and 972 Adelheid appears as intervenient in seventy-five charters. Additionally Adelheid and Otto I are named together in Papal bulls". She often protected the ecclesiastic institutions, seemingly to gain a sphere of influence separate from that of her husband. Between 991 and 993, the brothers of Feuchtwang wrote to her and requested to be "protected by the shadow of your rule from now on, we may be safe from the tumults of secular attacks". They promised they would pray for her so that her reign would be long and stable.

Adelaide wielded a great amount of power during her husband's reign, as evidenced by several requests made to her. A letter, written in the 980s by her daughter Emma demanded that Adelaide intervene against Emma's enemies and mobilize forces in the Ottonian Empire. She also asked that Adelaide capture Hugh Capet, who was already elected king of West Frankia in 987. Another enemy of Emma's was Charles, the brother of Emma's deceased consort Lothar, who had accused his sister-in-law of adultery. Another pleader was Gerbert of Aurillac, at that time archbishop of Reims (the later Pope Sylvester II), who wrote to Adelaide to ask for protection against his enemies. Buchinger remarks that, "These examples are remarkable, because they imply that Adelheid had the possibilities to help in both cases or at least Emma and Gerbert do believe that she could have intervened and succeeded. Both are themselves important political figures in their realm and still they rely on Adelheid. Adelheid’s power and importance must have been extremely stable and reliable to do as wished by the pleaders."

Otto II's era
In the years following Otto I's death, Adelaide exerted a powerful influence at court. However, Adelaide was in conflict with her daughter-in-law, the Byzantine princess Theophanu, as only one woman could be queen and hold the associated functions and powers at court. Adelaide was able to maintain the title imperatrix augusta even though Theophanu now also used it. Moreover, Theophanu opposed Adelaide in the use of her dowry lands, which Adelaide wanted to continue to use and donate to ecclesiastical institutions, ensuring her power base. Adelaide had the right to make transactions of her Italian lands as she pleased, but she needed the permission of the emperor to use her Ottonian lands. Adelaide also sided with her extended kin against Otto II. Wilson compares this action with those of other royal women: "Royal women possessed agency and did not always do the bidding of male relatives. Engelberge greatly influenced her husband, Emperor Louis II, in his attempts to extend imperial control to southern Italy in the 870s. Matilda’s favouritism for her younger son Heinrich caused Otto I considerable trouble, while Adelaide sided with her extended kin against her own son, Otto II, until he temporarily exiled her to Burgundy in 978. Agency was clearest during regencies, because these lacked formal rules, offering scope for forceful personalities to assert themselves." After being expelled from court by Otto II in 978, she divided her time between living in Italy in the royal palace of Pavia and Arles with her brother Conrad I, King of Burgundy, through whom she was finally reconciled with her son. In 983 (shortly before his death) Otto II appointed her his viceroy in Italy.

Regency
In 983, her son Otto II died and was succeeded by Adelaide's grandson Otto III under the regency of Theophanu while Adelaide remained in Italy. For some time, Adelaide and Theophanu were able to put aside their separate interests and work together to ensure Otto III's succession. This is seen through their joint appearance in the charters. According to the Annales Quedlinburgenses, after Otto II's death, Henry, duke of Bavaria kidnapped Otto III. The narrative claims that Adelaide returned from Lombardy to join with Theophanu, Matilda, and other leaders of Europe and reclaim the child.

When Theophanu died in 990, Adelaide assumed regency on behalf of Otto III until he reached legal majority four years later. Adelaide's role in establishing Otto's position can be seen in a letter Otto III wrote to his grandmother in 996: "According to your [Adelheid’s] wishes and desires, the divinity has conferred the rights of an empire on us [Otto III] with a happy outcome".

Troubles in the East continued under Adelaide, as Boleslaus of Bohemia wavered in his loyalty. In 992, there was war between Bohemia and Poland, and again like in Theophanu's time, the Ottonian regime sided with Poland. Jestice comments that, "Christianity was not re-established in the land of the Liutizi during their lifetimes. But there were territorial gains, and by 987 it was possible to begin rebuilding destroyed fortresses along the Elbe". A Saxon army, with Otto III's presence, took Brandenburg in 991. The Hildesheim annal reports that there was another expedition in 992.

Thietmar of Merseburg reports that Otto III dismissed his grandmother after his mother's death, but Althoff doubts this story. Even after Otto attained majority, Adelaide often accompanied him in his travels and influenced him, along with other women.

In Burgundy, Adelaide's homeland, the counts and castellans behaved increasingly independently from their king Rudolph III. Just before her death in 999, she had to intervene in Burgundy to restore peace.

Later years
Adelaide resigned as regent when Otto III was declared to be of the legal majority in 995. From then on, she devoted herself exclusively to her works of charity, in particular to the foundation and restoration of religious houses, i.e. monasteries, churches and abbeys.

Adelaide had long entertained close relations with Cluny, then the center of the movement for ecclesiastical reform, and in particular with its abbots Majolus and Odilo. She retired to a nunnery she had founded in c. 991 at Selz in Alsace.

On her way to Burgundy to support her nephew Rudolf III against a rebellion, she died at Selz Abbey on 16 December 999, days short of the millennium she thought would bring the Second Coming of Christ. She was buried in the Abbey and Pope Urban II canonized her in 1097. After serious flooding, which almost completely destroyed it in 1307, Adelaide's relics were moved elsewhere. A goblet reputed to have belonged to Saint Adelaide has long been preserved in Seltz.; it was used to give potions to people with fever and the healings were said to have been numerous. Adelaide constantly devoted herself to the service of the church and peace, and to the empire as guardian of both; she also interested herself in the conversion of the Slavs. She was thus a principal agent — almost an embodiment — of the work of the pre-schism Church at the end of the Early Middle Ages in the construction of the religious culture of Central Europe. Some of her relics are preserved in a shrine in Hanover. Her feast day, 16 December, is still kept in many German dioceses.

Issue
In 947, Adelaide was married to King Lothair II of Italy. The union produced one child:
 * Emma of Italy (948 – after 987), queen of France and wife of Lothair of France

In 951, Adelaide was married to King Otto I, the future Holy Roman Emperor. The union produced four children:
 * Henry (952 – 7 April 954)
 * Bruno (953 – 8 September 957)
 * Matilda (early 955 – † 6 February 999), the first Princess-Abbess of Quedlinburg
 * Otto II (end 955 – 7 December 983), later Holy Roman Emperor.

Historiography
Adelaide was one of the most important and powerful medieval female rulers. Historically, as empress and saint, she has been described as powerful, with both male attributes (like strength, justness and prudence) and female attributes (piety, self denying). Modern German historiography tends to focus on her contributions to the Ottonian dynasty and the development of the Holy Roman Empire.

Depictions in art
Adelaide is usually represented in the garb of an empress, with sceptre and crown. Since the 14th century, she is also given as an attribute a model church or a ship (by which she is said to have escaped from captivity).

The most famous representation of Adelaide in German art belongs to a group of sandstone figures in the choir of Meissen Cathedral, which was created around 1260. She is shown here with her husband, who was not canonized, since he founded the diocese of Meissen with her.

Operas

 * Adelaide of Burgundy is the main character of the opera l'Adelaide (1672) by Antonio Sartorio.
 * Adelaide is the subject of a 1723 opera by Nicola Porpora, where she was played by the great castrato Farinelli en travesti.
 * Lotario is a 1729 opera seria in three acts by George Frideric Handel. It is a fictionalisation of some events in the life of Adelaide.
 * Adelaide is the heroine of Adelaide di Borgogna, an opera with two acts (1817) by Gioachino Rossini (music) and Giovanni Schmidt (libretto).
 * Adelaide is the heroine of William Bernard McCabe's 1856 novel Adelaide, Queen of Italy, or The Iron Crown.

Books and novels

 * Adelheid, Mutter der Königreiche (Adelaide, Mother of Kingdoms) published in 1936 by Gertrud Bäumer.
 * Die fremde Königin (The Foreign Queen), published in 2017, Adelaide is one of the central characters in Rebecca Gablé's novel.
 * Empress Adelheid and Countess Matilda: medieval female rulership and the foundations of European society by Penelope Nash (2017).
 * Imperial ladies of the Ottonian Dynasty: women and rule in tenth-century Germany by Phyllis G. Jestice (2018)
 * God's Maidservant: The story of Adelaide of Italy (Women of the Dark Ages) by Anna Chant (2017)

Artwork

 * San Giuseppe con Gesù Bambino tra Sant'Adelaide, Sant'Antonio da Padova, San Lupo e San Michele arcangelo by Francesco Coghetti, 1828
 * Adelaide is a featured figure on Judy Chicago's installation piece The Dinner Party, being represented as one of the 999 names on the Heritage Floor, with the related place setting of Theodora (wife of Justinian I).

title: Adelaide of Italy


text:
Talk:Adelaide of Italy

Untitled
I cut:
 * and favoured an early form of evangelical Christianity.

Because I'm a medievalist and I have NO idea what an 'early form of evangelical Christianity' practiced by a canonized saint at the end of the first millennium would have been. Claiming that she was anything other than a Roman Catholic is - to say it moderately - odd. If what the author means is that having read the life of St. Adelaide he or she is impressed with her evident holiness, woo hoo! Maybe Catholicism isn't quite what you think it is! --MichaelTinkler

No problems: I was trying to cover the bases. I wasn't quite sure I believed it either. sjc

IP's changing of name in title of book
We can not change the spelling of a name that is in the title of a book or chapter such as this, page iii. The IP has on two occasions changed "Adelheid" to "Adelaide". --Kansas Bear (talk) 04:01, 29 February 2016 (UTC)

Adelheid?
This article seems very similar to Adelheid of Burgundy. Who is Adelaide?68.45.174.58 (talk) 00:34, 3 July 2016 (UTC)

External links modified
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Help for Cultural depictions of Adelaide of Italy,; Importance scale

 * I've created the article Cultural depictions of Adelaide of Italy but my access to sources on her as a religious figure and artworks depicting her as such is limited. Online access to Italian historiography concerning her is limited as well as I have trouble finding even summaries. Thank for any help!
 * Also I see that many wiki projects take an interest in her but the importance scale is low to mid. She should not be "rated" as such, even if Wiki does not claim that the importance scale correlates to the "level" of the personality in history. At least for the Holy Roman Empire and Germany. The reasons can be seen in my article.

-Deamonpen (talk) 19:16, 15 July 2022 (UTC)

title: Talk:Adelaide of Italy


text:
Airbus A300

The Airbus A300 is Airbus's first production aircraft and the world's first twin-engine, double-aisle wide-body airliner, developed and manufactured by Airbus from 1971 to 2007.

In September 1967, aircraft manufacturers in the United Kingdom, France, and West Germany signed an initial memorandum of understanding to collaborate to develop an innovative large airliner. West Germany and France reached a firm agreement on 29 May 1969, after the British withdrew from the project on 10 April 1969. The pan-European collaborative aerospace manufacturer Airbus Industrie was formally created on 18 December 1970 to develop and produce it. The A300 prototype first flew on 28 October 1972.

The first twin-engine widebody airliner, the A300 typically seats 247 passengers in two classes over a range of 5,375 to 7,500 km (2,900 to 4,050 nmi; 5,375 to 7,500 km).

Initial variants are powered by General Electric CF6-50 or Pratt & Whitney JT9D turbofans and have a three-crew flight deck. The improved A300-600 has a two-crew cockpit and updated CF6-80C2 or PW4000 engines; it made its first flight on 8 July 1983 and entered service later that year. The A300 is the basis of the smaller A310 (first flown in 1982) and was adapted in a freighter version. Its cross section was retained for the larger four-engined A340 (1991) and the larger twin-engined A330 (1992). It is also the basis for the oversize Beluga transport (1994).

Unlike most Airbus products, it has a yoke rather than a sidestick, and does not use a fly-by-wire system.

Launch customer Air France introduced the type on 23 May 1974. After limited demand initially, sales took off as the type was proven in early service, beginning three decades of steady orders. It has a similar capacity to the Boeing 767-300, introduced in 1986, but lacked the 767-300ER range. During the 1990s, the A300 became popular with cargo aircraft operators, as both passenger airliner conversions and as original builds. Production ceased in July 2007 after 561 deliveries. , there are 197 A300 family aircraft still in commercial service.

Origins

During the 1960s, European aircraft manufacturers such as Hawker Siddeley and the British Aircraft Corporation, based in the UK, and Sud Aviation of France, had ambitions to build a new 200-seat airliner for the growing civil aviation market. While studies were performed and considered, such as a stretched twin-engine variant of the Hawker Siddeley Trident and an expanded development of the British Aircraft Corporation (BAC) One-Eleven, designated the BAC Two-Eleven, it was recognized that if each of the European manufacturers were to launch similar aircraft into the market at the same time, neither would achieve sales volume needed to make them viable. In 1965, a British government study, known as the Plowden Report, had found British aircraft production costs to be between 10% and 20% higher than American counterparts due to shorter production runs, which was in part due to the fractured European market. To overcome this factor, the report recommended the pursuit of multinational collaborative projects between the region's leading aircraft manufacturers.

European manufacturers were keen to explore prospective programmes; the proposed 260-seat wide-body HBN 100 between Hawker Siddeley, Nord Aviation, and Breguet Aviation being one such example. National governments were also keen to support such efforts amid a belief that American manufacturers could dominate the European Economic Community; in particular, Germany had ambitions for a multinational airliner project to invigorate its aircraft industry, which had declined considerably following the Second World War. During the mid-1960s, both Air France and American Airlines had expressed interest in a short-haul twin-engine wide-body aircraft, indicating a market demand for such an aircraft to be produced. In July 1967, during a high-profile meeting between French, German, and British ministers, an agreement was made for greater cooperation between European nations in the field of aviation technology, and "for the joint development and production of an airbus". The word airbus at this point was a generic aviation term for a larger commercial aircraft, and was considered acceptable in multiple languages, including French.

Shortly after the July 1967 meeting, French engineer Roger Béteille was appointed as the technical director of what would become the A300 programme, while Henri Ziegler, chief operating office of Sud Aviation, was appointed as the general manager of the organisation and German politician Franz Josef Strauss became the chairman of the supervisory board. Béteille drew up an initial work share plan for the project, under which French firms would produce the aircraft's cockpit, the control systems, and lower-centre portion of the fuselage, Hawker Siddeley would manufacture the wings, while German companies would produce the forward, rear and upper part of the center fuselage sections. Additional work included moving elements of the wings being produced in the Netherlands, and Spain producing the horizontal tail plane.

An early design goal for the A300 that Béteille had stressed the importance of was the incorporation of a high level of technology, which would serve as a decisive advantage over prospective competitors. For this reason, the A300 would feature the first use of composite materials of any passenger aircraft, the leading and trailing edges of the tail fin being composed of glass fibre reinforced plastic. Béteille opted for English as the working language for the developing aircraft, as well against using Metric instrumentation and measurements, as most airlines already had US-built aircraft. These decisions were partially influenced by feedback from various airlines, such as Air France and Lufthansa, as an emphasis had been placed on determining the specifics of what kind of aircraft that potential operators were seeking. According to Airbus, this cultural approach to market research had been crucial to the company's long-term success.

Workshare and redefinition
On 26 September 1967, the British, French, and West German governments signed a Memorandum of Understanding to start development of the 300-seat Airbus A300. At this point, the A300 was only the second major joint aircraft programme in Europe, the first being the Anglo-French Concorde. Under the terms of the memorandum, Britain and France were each to receive a 37.5 per cent work share on the project, while Germany received a 25 per cent share. Sud Aviation was recognized as the lead company for A300, with Hawker Siddeley being selected as the British partner company. At the time, the news of the announcement had been clouded by the British Government's support for the Airbus, which coincided with its refusal to back BAC's proposed competitor, the BAC 2–11, despite a preference for the latter expressed by British European Airways (BEA). Another parameter was the requirement for a new engine to be developed by Rolls-Royce to power the proposed airliner; a derivative of the in-development Rolls-Royce RB211, the triple-spool RB207, capable of producing of 47500 lbf. The programme cost was US$4.6 billion (in 1993 dollars, equivalent to $ in ).

In December 1968, the French and British partner companies (Sud Aviation and Hawker Siddeley) proposed a revised configuration, the 250-seat Airbus A250. It had been feared that the original 300-seat proposal was too large for the market, thus it had been scaled down to produce the A250. The dimensional changes involved in the shrink reduced the length of the fuselage by 5.62 m and the diameter by 0.8 m, reducing the overall weight by 25 t. For increased flexibility, the cabin floor was raised so that standard LD3 freight containers could be accommodated side-by-side, allowing more cargo to be carried. Refinements made by Hawker Siddeley to the wing's design provided for greater lift and overall performance; this gave the aircraft the ability to climb faster and attain a level cruising altitude sooner than any other passenger aircraft. It was later renamed the A300B.

Perhaps the most significant change of the A300B was that it would not require new engines to be developed, being of a suitable size to be powered by Rolls-Royce's RB211, or alternatively the American Pratt & Whitney JT9D and General Electric CF6 powerplants; this switch was recognized as considerably reducing the project's development costs. To attract potential customers in the US market, it was decided that General Electric CF6-50 engines would power the A300 in place of the British RB207; these engines would be produced in co-operation with French firm Snecma. By this time, Rolls-Royce had been concentrating their efforts upon developing their RB211 turbofan engine instead and progress on the RB207's development had been slow for some time, the firm having suffered due to funding limitations, both of which had been factors in the engine switch decision.

On 10 April 1969, a few months after the decision to drop the RB207 had been announced, the British government announced that they would withdraw from the Airbus venture. In response, West Germany proposed to France that they would be willing to contribute up to 50% of the project's costs if France was prepared to do the same. Additionally, the managing director of Hawker Siddeley, Sir Arnold Alexander Hall, decided that his company would remain in the project as a favoured sub-contractor, developing and manufacturing the wings for the A300, which would later become pivotal in later versions' impressive performance from short domestic to long intercontinental flights. Hawker Siddeley spent £35 million of its own funds, along with a further £35 million loan from the West German government, on the machine tooling to design and produce the wings.

Programme launch

On 29 May 1969, during the Paris Air Show, French transport minister Jean Chamant and German economics minister Karl Schiller signed an agreement officially launching the Airbus A300, the world's first twin-engine widebody airliner. The intention of the project was to produce an aircraft that was smaller, lighter, and more economical than its three-engine American rivals, the McDonnell Douglas DC-10 and the Lockheed L-1011 TriStar. In order to meet Air France's demands for an aircraft larger than 250-seat A300B, it was decided to stretch the fuselage to create a new variant, designated as the A300B2, which would be offered alongside the original 250-seat A300B, henceforth referred to as the A300B1. On 3 September 1970, Air France signed a letter of intent for six A300s, marking the first order to be won for the new airliner.

In the aftermath of the Paris Air Show agreement, it was decided that, in order to provide effective management of responsibilities, a Groupement d'intérêt économique would be established, allowing the various partners to work together on the project while remaining separate business entities. On 18 December 1970, Airbus Industrie was formally established following an agreement between Aérospatiale (the newly merged Sud Aviation and Nord Aviation) of France and the antecedents to Deutsche Aerospace of Germany, each receiving a 50 per cent stake in the newly formed company. In 1971, the consortium was joined by a third full partner, the Spanish firm CASA, who received a 4.2 per cent stake, the other two members reducing their stakes to 47.9 per cent each. In 1979, Britain joined the Airbus consortium via British Aerospace, which Hawker Siddeley had merged into, which acquired a 20 per cent stake in Airbus Industrie with France and Germany each reducing their stakes to 37.9 per cent.

Prototype and flight testing

Airbus Industrie was initially headquartered in Paris, which is where design, development, flight testing, sales, marketing, and customer support activities were centred; the headquarters was relocated to Toulouse in January 1974. The final assembly line for the A300 was located adjacent to Toulouse Blagnac International Airport. The manufacturing process necessitated transporting each aircraft section being produced by the partner companies scattered across Europe to this one location. The combined use of ferries and roads were used for the assembly of the first A300, however this was time-consuming and not viewed as ideal by Felix Kracht, Airbus Industrie's production director. Kracht's solution was to have the various A300 sections brought to Toulouse by a fleet of Boeing 377-derived Aero Spacelines Super Guppy aircraft, by which means none of the manufacturing sites were more than two hours away. Having the sections airlifted in this manner made the A300 the first airliner to use just-in-time manufacturing techniques, and allowed each company to manufacture its sections as fully equipped, ready-to-fly assemblies.

In September 1969, construction of the first prototype A300 began. On 28 September 1972, this first prototype was unveiled to the public, it conducted its maiden flight from Toulouse–Blagnac International Airport on 28 October that year. This maiden flight, which was performed a month ahead of schedule, lasted for one hour and 25 minutes; the captain was Max Fischl and the first officer was Bernard Ziegler, son of Henri Ziegler. In 1972, unit cost was US$17.5M. On 5 February 1973, the second prototype performed its maiden flight. The flight test programme, which involved a total of four aircraft, was relatively problem-free, accumulating 1,580 flight hours throughout. In September 1973, as part of promotional efforts for the A300, the new aircraft was taken on a six-week tour around North America and South America, to demonstrate it to airline executives, pilots, and would-be customers. Amongst the consequences of this expedition, it had allegedly brought the A300 to the attention of Frank Borman of Eastern Airlines, one of the "big four" U.S. airlines.

Entry into service
On 15 March 1974, type certificates were granted for the A300 from both German and French authorities, clearing the way for its entry into revenue service. On 23 May 1974, Federal Aviation Administration (FAA) certification was received. The first production model, the A300B2, entered service in 1974, followed by the A300B4 one year later. Initially, the success of the consortium was poor, in part due to the economic consequences of the 1973 oil crisis,   but by 1979 there were 81 A300 passenger liners in service with 14 airlines, alongside 133 firm orders and 88 options. Ten years after the official launch of the A300, the company had achieved a 26 per cent market share in terms of dollar value, enabling Airbus to proceed with the development of its second aircraft, the Airbus A310.

Design

The Airbus A300 is a wide-body medium-to-long range airliner; it has the distinction of being the first twin-engine wide-body aircraft in the world. In 1977, the A300 became the first Extended Range Twin Operations (ETOPS)-compliant aircraft, due to its high performance and safety standards. Another world-first of the A300 is the use of composite materials on a commercial aircraft, which were used on both secondary and later primary airframe structures, decreasing overall weight and improving cost-effectiveness. Other firsts included the pioneering use of centre-of-gravity control, achieved by transferring fuel between various locations across the aircraft, and electrically signalled secondary flight controls.

The A300 is powered by a pair of underwing turbofan engines, either General Electric CF6 or Pratt & Whitney JT9D engines; the sole use of underwing engine pods allowed for any suitable turbofan engine to be more readily used. The lack of a third tail-mounted engine, as per the trijet configuration used by some competing airliners, allowed for the wings to be located further forwards and to reduce the size of the vertical stabiliser and elevator, which had the effect of increasing the aircraft's flight performance and fuel efficiency.

Airbus partners had employed the latest technology, some of which having been derived from Concorde, on the A300. According to Airbus, new technologies adopted for the airliner were selected principally for increased safety, operational capability, and profitability. Upon entry into service in 1974, the A300 was a very advanced plane, which went on to influence later airliner designs. The technological highlights include advanced wings by de Havilland (later BAE Systems) with supercritical airfoil sections for economical performance and advanced aerodynamically efficient flight control surfaces. The 5.64 m diameter circular fuselage section allows an eight-abreast passenger seating and is wide enough for 2 LD3 cargo containers side by side. Structures are made from metal billets, reducing weight. It is the first airliner to be fitted with wind shear protection. Its advanced autopilots are capable of flying the aircraft from climb-out to landing, and it has an electrically controlled braking system.

Later A300s incorporated other advanced features such as the Forward-Facing Crew Cockpit (FFCC), which enabled a two-pilot flight crew to fly the aircraft alone without the need for a flight engineer, the functions of which were automated; this two-man cockpit concept was a world-first for a wide-body aircraft. Glass cockpit flight instrumentation, which used cathode ray tube (CRT) monitors to display flight, navigation, and warning information, along with fully digital dual autopilots and digital flight control computers for controlling the spoilers, flaps, and leading-edge slats, were also adopted upon later-built models. Additional composites were also made use of, such as carbon-fibre-reinforced polymer (CFRP), as well as their presence in an increasing proportion of the aircraft's components, including the spoilers, rudder, air brakes, and landing gear doors. Another feature of later aircraft was the addition of wingtip fences, which improved aerodynamic performance and thus reduced cruise fuel consumption by about 1.5% for the A300-600.

In addition to passenger duties, the A300 became widely used by air freight operators; according to Airbus, it is the best-selling freight aircraft of all time. Various variants of the A300 were built to meet customer demands, often for diverse roles such as aerial refueling tankers, freighter models (new-build and conversions), combi aircraft, military airlifter, and VIP transport. Perhaps the most visually unique of the variants is the A300-600ST Beluga, an oversized cargo-carrying model operated by Airbus to carry aircraft sections between their manufacturing facilities. The A300 was the basis for, and retained a high level of commonality with, the second airliner produced by Airbus, the smaller Airbus A310.

Operational history

On 23 May 1974, the first A300 to enter service performed the first commercial flight of the type, flying from Paris to London, for Air France.

Immediately after the launch, sales of the A300 were weak for some years, with most orders going to airlines that had an obligation to favor the domestically made product – notably Air France and Lufthansa, the first two airlines to place orders for the type. Following the appointment of Bernard Lathière as Henri Ziegler's replacement, an aggressive sales approach was adopted. Indian Airlines was the world's first domestic airline to purchase the A300, ordering three aircraft with three options. However, between December 1975 and May 1977, there were no sales for the type. During this period a number of "whitetail" A300s – completed but unsold aircraft – were completed and stored at Toulouse, and production fell to half an aircraft per month amid calls to pause production completely.

During the flight testing of the A300B2, Airbus held a series of talks with Korean Air on the topic of developing a longer-range version of the A300, which would become the A300B4. In September 1974, Korean Air placed an order for four A300B4s with options for two further aircraft; this sale was viewed as significant as it was the first non-European international airline to order Airbus aircraft. Airbus had viewed South-East Asia as a vital market that was ready to be opened up and believed Korean Air to be the 'key'.

Airlines operating the A300 on short-haul routes were forced to reduce frequencies to try and fill the aircraft. As a result, they lost passengers to airlines operating more frequent narrow-body flights. Eventually, Airbus had to build its own narrowbody aircraft (the A320) to compete with the Boeing 737 and McDonnell Douglas DC-9/MD-80. The saviour of the A300 was the advent of ETOPS, a revised FAA rule which allows twin-engine jets to fly long-distance routes that were previously off-limits to them. This enabled Airbus to develop the aircraft as a medium/long-range airliner.

In 1977, US carrier Eastern Air Lines leased four A300s as an in-service trial. CEO Frank Borman was impressed that the A300 consumed 30% less fuel, even less than expected, than his fleet of L-1011s. Borman proceeded to order 23 A300s, becoming the first U.S. customer for the type. This order is often cited as the point at which Airbus came to be seen as a serious competitor to the large American aircraft-manufacturers Boeing and McDonnell Douglas. Aviation author John Bowen alleged that various concessions, such as loan guarantees from European governments and compensation payments, were a factor in the decision as well. The Eastern Air Lines breakthrough was shortly followed by an order from Pan Am. From then on, the A300 family sold well, eventually reaching a total of 561 delivered aircraft.

In December 1977, Aerocondor Colombia became the first Airbus operator in Latin America, leasing one Airbus A300B4-2C, named Ciudad de Barranquilla.

During the late 1970s, Airbus adopted a so-called 'Silk Road' strategy, targeting airlines in the Far East. As a result, The aircraft found particular favor with Asian airlines, being bought by Japan Air System, Korean Air, China Eastern Airlines, Thai Airways International, Singapore Airlines, Malaysia Airlines, Philippine Airlines, Garuda Indonesia, China Airlines, Pakistan International Airlines, Indian Airlines, Trans Australia Airlines and many others. As Asia did not have restrictions similar to the FAA 60-minutes rule for twin-engine airliners which existed at the time, Asian airlines used A300s for routes across the Bay of Bengal and South China Sea. In 1977, the A300B4 became the first ETOPS compliant aircraft, qualifying for Extended Twin Engine Operations over water, providing operators with more versatility in routing. In 1982 Garuda Indonesia became the first airline to fly the A300B4-200FFCC with the newly Forward-Facing Crew Cockpit concept, the world's first wide-body aircraft that only operated by two-man cockpit crew. By 1981, Airbus was growing rapidly, with over 400 aircraft sold to over forty airlines.

In 1989, Chinese operator China Eastern Airlines received its first A300; by 2006, the airline operated around 18 A300s, making it the largest operator of both the A300 and the A310 at that time. On 31 May 2014, China Eastern officially retired the last A300-600 in its fleet, having begun drawing down the type in 2010.

From 1997 to 2014, a single A300, designated A300 Zero-G, was operated by the European Space Agency (ESA), centre national d'études spatiales (CNES) and the German Aerospace Center (DLR) as a reduced-gravity aircraft for conducting research into microgravity; the A300 is the largest aircraft to ever have been used in this capacity. A typical flight would last for two and a half hours, enabling up to 30 parabolas to be performed per flight.

By the 1990s, the A300 was being heavily promoted as a cargo freighter. The largest freight operator of the A300 is FedEx Express, which has 65 A300 aircraft in service as of May 2022. UPS Airlines also operates 52 freighter versions of the A300.

The final version was the A300-600R and is rated for 180-minute ETOPS. The A300 has enjoyed renewed interest in the secondhand market for conversion to freighters; large numbers were being converted during the late 1990s. The freighter versions – either new-build A300-600s or converted ex-passenger A300-600s, A300B2s and B4s – account for most of the world's freighter fleet after the Boeing 747 freighter.

The A300 provided Airbus the experience of manufacturing and selling airliners competitively. The basic fuselage of the A300 was later stretched (A330 and A340), shortened (A310), or modified into derivatives (A300-600ST Beluga Super Transporter). In 2006, unit cost of an −600F was $105 million. In March 2006, Airbus announced the impending closure of the A300/A310 final assembly line, making them the first Airbus aircraft to be discontinued. The final production A300, an A300F freighter, performed its initial flight on 18 April 2007, and was delivered to FedEx Express on 12 July 2007. Airbus has announced a support package to keep A300s flying commercially. Airbus offers the A330-200F freighter as a replacement for the A300 cargo variants.

The life of UPS's fleet of 52 A300s, delivered from 2000 to 2006, will be extended to 2035 by a flight deck upgrade based around Honeywell Primus Epic avionics; new displays and flight management system (FMS), improved weather radar, a central maintenance system, and a new version of the current enhanced ground proximity warning system. With a light usage of only two to three cycles per day, it will not reach the maximum number of cycles by then. The first modification will be made at Airbus Toulouse in 2019 and certified in 2020.

As of July 2017, there are 211 A300s in service with 22 operators, with the largest operator being FedEx Express with 68 A300-600F aircraft.

A300B1

The A300B1 was the first variant to take flight. It had a maximum takeoff weight (MTOW) of 291000 lb, was 167 ft long and was powered by two General Electric CF6-50A engines. Only two prototypes of the variant were built before it was adapted into the A300B2, the first production variant of the airliner. The second prototype was leased to Trans European Airways in 1974.

A300B2-100
Responding to a need for more seats from Air France, Airbus decided that the first production variant should be larger than the original prototype A300B1. The CF6-50A powered A300B2-100 was 2.6 m longer than the A300B1 and had an increased MTOW of 137 t, allowing for 30 additional seats and bringing the typical passenger count up to 281, with capacity for 20 LD3 containers. Two prototypes were built and the variant made its maiden flight on 28 June 1973, became certified on 15 March 1974 and entered service with Air France on 23 May 1974.

A300B2-200
For the A300B2-200, originally designated as the A300B2K, Krueger flaps were introduced at the leading-edge root, the slat angles were reduced from 20 degrees to 16 degrees, and other lift related changes were made in order to introduce a high-lift system. This was done to improve performance when operating at high-altitude airports, where the air is less dense and lift generation is reduced. The variant had an increased MTOW of 142 t and was powered by CF6-50C engines, was certified on 23 June 1976, and entered service with South African Airways in November 1976. CF6-50C1 and CF6-50C2 models were also later fitted depending on customer requirements, these became certified on 22 February 1978 and 21 February 1980 respectively.

A300B2-320
The A300B2-320 introduced the Pratt & Whitney JT9D powerplant and was powered by JT9D-59A engines. It retained the 142 t MTOW of the B2-200, was certified on 4 January 1980, and entered service with Scandinavian Airlines on 18 February 1980, with only four being produced.

A300B4-100
The initial A300B4 variant, later named the A300B4-100, included a centre fuel tank for an increased fuel capacity of 47.5 t, and had an increased MTOW of 157.5 t. It also featured Krueger flaps and had a similar high-lift system to what was later fitted to the A300B2-200. The variant made its maiden flight on 26 December 1974, was certified on 26 March 1975, and entered service with Germanair in May 1975.

A300B4-200
The A300B4-200 had an increased MTOW of 165 t and featured an additional optional fuel tank in the rear cargo hold, which would reduce the cargo capacity by two LD3 containers. The variant was certified on 26 April 1979.

A300-600

The A300-600, officially designated as the A300B4-600, was slightly longer than the A300B2 and A300B4 variants and had an increased interior space from using a similar rear fuselage to the Airbus A310, this allowed it to have two additional rows of seats. It was initially powered by Pratt & Whitney JT9D-7R4H1 engines, but was later fitted with General Electric CF6-80C2 engines, with Pratt & Whitney PW4156 or PW4158 engines being introduced in 1986. Other changes include an improved wing featuring a recambered trailing edge, the incorporation of simpler single-slotted Fowler flaps, the deletion of slat fences, and the removal of the outboard ailerons after they were deemed unnecessary on the A310. The variant made its first flight on 8 July 1983, was certified on 9 March 1984, and entered service in June 1984 with Saudi Arabian Airlines. A total of 313 A300-600s (all versions) have been sold. The A300-600 uses the A310 cockpits, featuring digital technology and electronic displays, eliminating the need for a flight engineer. The FAA issues a single type rating which allows operation of both the A310 and A300-600.
 * A300-600: (Official designation: A300B4-600) The baseline model of the −600 series.
 * A300-620C: (Official designation: A300C4-620) A convertible-freighter version. Four delivered between 1984 and 1985.
 * A300-600F: (Official designation: A300F4-600) The freighter version of the baseline −600.
 * A300-600R: (Official designation: A300B4-600R) The increased-range −600, achieved by an additional trim fuel tank in the tail. First delivery in 1988 to American Airlines; all A300s built since 1989 (freighters included) are −600Rs. Japan Air System (later merged into Japan Airlines) took delivery of the last new-built passenger A300, an A300-622R, in November 2002.
 * A300-600RC: (Official designation: A300C4-600R) The convertible-freighter version of the −600R. Two were delivered in 1999.
 * A300-600RF: (Official designation: A300F4-600R) The freighter version of the −600R. All A300s delivered between November 2002 and 12 July 2007 (last ever A300 delivery) were A300-600RFs.

A300B10 (A310)

Airbus had demand for an aircraft smaller than the A300. On 7 July 1978, the A310 (initially the A300B10) was launched with orders from Swissair and Lufthansa. On 3 April 1982, the first prototype conducted its maiden flight and it received its type certification on 11 March 1983.

Keeping the same eight-abreast cross-section, the A310 is 6.95 m shorter than the initial A300 variants, and has a smaller 219 m2 wing, down from 260 m2. The A310 introduced a two-crew glass cockpit, later adopted for the A300-600 with a common type rating. It was powered by the same GE CF6-80 or Pratt & Whitney JT9D then PW4000 turbofans. It can seat 220 passengers in two classes, or 240 in all-economy, and can fly up to 5150 nmi. It has overwing exits between the two main front and rear door pairs.

In April 1983, the aircraft entered revenue service with Swissair and competed with the Boeing 767–200, introduced six months before. Its longer range and ETOPS regulations allowed it to be operated on transatlantic flights. Until the last delivery in June 1998, 255 aircraft were produced, as it was succeeded by the larger Airbus A330-200.

It has cargo aircraft versions, and was derived into the Airbus A310 MRTT military tanker/transport.

A300-600ST

Commonly referred to as the Airbus Beluga or "Airbus Super Transporter", these five airframes are used by Airbus to ferry parts between the company's disparate manufacturing facilities, thus enabling workshare distribution. They replaced the four Aero Spacelines Super Guppys previously used by Airbus.

ICAO code: A3ST

Operators
, there are 197 A300 family aircraft in commercial service. The five largest operators were FedEx Express (70), UPS Airlines (52), European Air Transport Leipzig (23), Iran Air (11), and Mahan Air (11).

Deliveries
Data through end of December 2007.

Accidents and incidents
As of June 2021, the A300 has been involved in 77 occurrences including 24 hull-loss accidents causing 1133 fatalities, and criminal occurrences and hijackings causing  fatalities.

Accidents with fatalities

 * 21 September 1987: An Egyptair Airbus A300B4-203 touched down 700 m past the runway threshold during a training flight. The right main gear hit the runway lights and the aircraft collided with an antenna and fences. No passengers were on board the plane, but 5 crew members were killed. The aircraft was written off. This was the first fatal accident of an Airbus A300.
 * 28 September 1992: PIA Flight 268, an A300B4 crashed on approach near Kathmandu, Nepal. All 12 crew and 155 passengers died.
 * 26 April 1994: China Airlines Flight 140 (Taiwan) crashed at the end of runway at Nagoya, Japan, killing all 15 crew and 249 of 256 passengers on board.
 * 26 September 1997: Garuda Indonesia Flight 152 was on approach to Polonia International Airport in Medan. The plane later crashed into a ravine in Buah Nabar due to ATC error and apparent haze that covers the country which limits the visibility. All 234 passengers and crew aboard were killed in Indonesia's deadliest crash.
 * 16 February 1998: China Airlines Flight 676 (Taiwan) crashed into a residential area close to CKS International Airport near Taipei, Taiwan. All 196 people on board were killed, including Taiwan's central bank president. Six people on the ground were also killed.
 * 12 November 2001: American Airlines Flight 587 crashed into Belle Harbor—a neighbourhood in Queens, New York, United States—shortly after takeoff from John F. Kennedy International Airport. The vertical stabiliser ripped off the aircraft after the rudder was mishandled during wake turbulence. All 260 people on board were killed, along with 5 people on the ground. It is the second-deadliest incident involving an A300 to date and the second-deadliest aircraft incident on United States soil.
 * 14 April 2010: AeroUnion Flight 302, an A300B4-203F, crashed on a road 2 km short of the runway while attempting to land at Monterrey Airport in Mexico. Seven people (five crew members and two on the ground) were killed.
 * 14 August 2013: UPS Flight 1354, an Airbus A300F4-622R, crashed outside the perimeter fence on approach to Birmingham–Shuttlesworth International Airport in Birmingham, Alabama, United States. Both crew members died.

Hull losses

 * 18 December 1983: Malaysian Airline System Flight 684, an Airbus A300B4 leased from Scandinavian Airlines System (SAS), registration OY-KAA, crashed short of the runway at Kuala Lumpur in bad weather while attempting to land on a flight from Singapore. All 247 people aboard escaped unharmed but the aircraft was destroyed in the resulting fire.
 * 24 April 1993: an Air Inter Airbus A300B2-1C was written off after colliding with a light pole while being pushed back at Montpellier.
 * In November 1993, an Indian Airlines A300 plane crash landed near Hyderabad airport. There were no deaths but the aircraft was written off.
 * 10 August 1994 – Korean Air Flight 2033 (Airbus A300) from Seoul to Jeju, the flight approached faster than usual to avoid potential windshear. Fifty feet above the runway the co-pilot, who was not flying the aircraft, decided that there was insufficient runway left to land and tried to perform a go-around against the captain's wishes.[18] The aircraft touched down 1,773 meters beyond the runway threshold. The aircraft could not be stopped on the remaining 1,227 meters of runway and overran at a speed of 104 knots. After striking the airport wall and a guard post at 30 knots, the aircraft burst into flames and was incinerated. The cabin crew was credited with safely evacuating all passengers although only half of the aircraft's emergency exits were usable.
 * 17 October 2001, Pakistan International Airlines flight PK231, registration AP-BCJ, from Islamabad via Peshawar to Dubai veered off the side of the runway after the right hand main landing gear collapsed as it touched down. The aircraft skidded and eventually came to rest in sand 50 meters from the runway. The aircraft sustained damage to its right wing structure and its no. 2 engine, which partly broke off the wing. All 205 passengers and crew survived.
 * 1 March 2004, Pakistan International Airlines Flight 2002 burst 2 tyres whilst taking off from King Abdulaziz International Airport. Fragments of the tyre were ingested by the engines, this caused the engines to catch fire and an aborted takeoff was performed. Due to the fire substantial damage to the engine and the left wing caused the aircraft to be written off. All 261 passengers and 12 crew survived.
 * 16 November 2012: an Air Contractors Airbus A300B4-203(F) EI-EAC, operating flight QY6321 on behalf of EAT Leipzig from Leipzig (Germany) to Bratislava (Slovakia), suffered a nose wheel collapse during roll out after landing at Bratislava's M. R. Štefánik Airport. All three crew members survived unharmed, the aircraft was written off. As of December 2017, the aircraft still was parked at a remote area of the airport between runways 13 and 22.
 * 12 October 2015: An Airbus A300B4-200F Freighter operated by Egyptian Tristar cargo carrier crashed in Mogadishu, Somalia. All the passengers and crew members survived the crash.
 * 1 October 2016: An Airbus A300-B4 registration PR-STN on a cargo flight between São Paulo-Guarulhos and Recife suffered a runway excursion after landing and the aft gear collapsed upon touchdown.

Violent incidents

 * 27 June 1976: Air France Flight 139, originating in Tel Aviv, Israel and carrying 248 passengers and a crew of 12 took off from Athens, Greece, headed for Paris, France. The flight was hijacked by terrorists, and was eventually flown to Entebbe Airport in Uganda. At the airport, Israeli commandos rescued 102 of the 106 hostages.
 * 26 October 1986: Thai Airways Flight 620, an Airbus A300B4-601, originating in Bangkok suffered an explosion mid-flight. The aircraft descended rapidly and was able to land safely at Osaka. The aircraft was later repaired and there were no fatalities. The cause was a hand grenade brought onto the plane by a Japanese gangster of the Yamaguchi-gumi. 62 of the 247 people on board were injured.
 * 3 July 1988: Iran Air Flight 655 was shot down by USS Vincennes in the Persian Gulf after being mistaken for an attacking Iranian F-14 Tomcat, killing all 290 passengers and crew.
 * 15 February 1991: two Kuwait Airways A300C4-620s and two Boeing 767s that had been seized during Iraq's occupation of Kuwait were destroyed in coalition bombing of Mosul Airport.
 * 24 December 1994: Air France Flight 8969 was hijacked at Houari Boumedienne Airport in Algiers, by four terrorists who belonged to the Armed Islamic Group. The terrorists apparently intended to crash the plane over the Eiffel Tower on Boxing Day. After a failed attempt to leave Marseille following a confrontational firefight between the terrorists and the GIGN French Special Forces, the result was the death of all four terrorists. (Snipers on the terminal front's roof shot dead two of the terrorists. The other two terrorists died as a result of gunshots in the cabin after approximately 20 minutes.) Three hostages including a Vietnamese diplomat were executed in Algiers, 229 hostages survived, many of them wounded by shrapnel. The almost 15-year-old aircraft was written off.
 * 24 December 1999: Indian Airlines Flight IC 814 from Kathmandu, Nepal, to New Delhi was hijacked. After refuelling and offloading a few passengers, the flight was diverted to Kandahar, Afghanistan. A Nepalese man was murdered while the plane was in flight.
 * 22 November 2003: European Air Transport OO-DLL, operating on behalf of DHL Aviation, was hit by an SA-14 'Gremlin' missile after takeoff from Baghdad International Airport. The aeroplane lost hydraulic pressure and thus the controls. After extending the landing gear to create more drag, the crew piloted the plane using differences in engine thrust and landed the plane with minimal further damage. The plane was repaired and offered for sale, but in April 2011 it still remained parked at Baghdad Intl.
 * 25 August 2011: an A300B4-620 5A-IAY of Afriqiyah Airways and A300B4-622 5A-DLZ of Libyan Arab Airlines were both destroyed in fighting between pro- and anti-Gaddafi forces at Tripoli International Airport.

Aircraft on display
Fifteen A300s are currently preserved:
 * F-BUAD Airbus A300 ZERO-G, since August 2015 preserved at Cologne Bonn Airport, Germany.
 * ex-HL7219 Korean Air Airbus A300B4 preserved at Korean Air Jeongseok Airfield.
 * ex-N11984 Continental Airlines Airbus A300B4 preserved in South Korea as a Night Flight Restaurant.
 * ex TC-ACD and TC-ACE Air ACT, preserved as coffee house at Uçak Cafe in Burhaniye, Turkey.
 * ex TC-MNJ MNG Airlines, preserved as Köfte Airlines restaurant at Tekirdağ, Turkey.
 * ex TC-FLA Fly Air, preserved as the Airbus Cafe & Restaurant at Kayseri, Turkey.
 * ex TC-ACC Air ACT, preserved as the Uçak Kütüphane library and education centre at Çankırı, Turkey.
 * ex EP-MHA Mahan Air, preserved as instructional airframe at the Botia Mahan Aviation College at Kerman, Iran.
 * ex TC-FLM Fly Air, preserved as a restaurant at Istanbul, Turkey.
 * ex B-18585 China Airlines, preserved as the Flight of Happiness restaurant at Taoyuan, Taiwan.
 * ex-PK-JID Sempati Air Airbus A300B4 repainted in first A300B1 prototype colours, including original F-WUAB registration, became an exhibit in 2014 at the Aeroscopia museum in Blagnac, near Toulouse, France.
 * ex TC-MCE MNG Airlines, preserved as a restaurant at the Danialand theme park at Agadir, Morocco.
 * ex HL7240 Korean Air, preserved as instructional airframe (gate guard) at the Korea Aerospace University at Goyang, South Korea.
 * ex HS-TAM Thai Airways A300-600R, preserved in a field near Doi Saket, Chiang Mai.

title: Airbus A300


text:
Agostino Carracci

Agostino Carracci (or Caracci; ; 16 August 1557 – 22 March 1602) was an Italian painter, printmaker, tapestry designer, and art teacher. He was, together with his brother, Annibale Carracci, and cousin, Ludovico Carracci, one of the founders of the Accademia degli Incamminati (Academy of the Progressives) in Bologna. Intended to devise alternatives to the Mannerist style favored in the preceding decades, this teaching academy helped propel painters of the School of Bologna to prominence.

Life
Agostino Carracci was born in Bologna as the son of a tailor. He was the elder brother of Annibale Carracci and the cousin of Ludovico Carracci. He initially trained as a goldsmith. He later studied painting, first with Prospero Fontana, who had been Lodovico's master, and later with Bartolomeo Passarotti. He traveled to Parma to study the works of Correggio. Accompanied by his brother Annibale, he spent a long time in Venice, where he trained as an engraver under the renowned Cornelis Cort. Starting from 1574 he worked as a reproductive engraver, copying works of 16th century masters such as Federico Barocci, Tintoretto, Antonio Campi, Veronese and Correggio. He also produced some original prints, including two etchings.

He traveled to Venice (1582, 1587–1589) and Parma (1586–1587). Together with Annibale and Ludovico he worked in Bologna on the fresco cycles in Palazzo Fava (Histories of Jason and Medea, 1584) and Palazzo Magnani (Histories of Romulus, 1590–1592). In 1592 he also painted the Communion of St. Jerome, now in the Pinacoteca di Bologna and considered his masterwork. In 1620, Giovanni Lanfranco, a pupil of the Carracci, famously accused another Carracci student, Domenichino, of plagiarizing this painting. From 1586 is his altarpiece of the Madonna with Child and Saints, in the National Gallery of Parma. In 1598 Carracci joined his brother Annibale in Rome, to collaborate on the decoration of the Gallery in Palazzo Farnese. From 1598 to 1600 is a triple Portrait, now in Naples, an example of genre painting. In 1600 he was called to Parma by Duke Ranuccio I Farnese to begin the decoration of the Palazzo del Giardino, but he died before it was finished. His friend the poet Claudio Achillini composed an epitaph, which was later published by Carlo Cesare Malvasia in the life of the Carracci.

Agostino's son Antonio Carracci was also a painter, and attempted to compete with his father's Academy.

An engraving by Agostino Carraci after the painting Love in the Golden Age by the 16th-century Flemish painter Paolo Fiammingo was the inspiration for Matisse's Le bonheur de vivre (Joy of Life).

Critical evaluation
While his undoubted value in the graphic field is widely recognised, Agostino, as a painter, although admired by his contemporaries, ended up being overshadowed by the fame of his brother Annibale. Perhaps even his long practice of engraving ended up putting him at disadvantage, since he might have been perceived as more inclined to copy than to create.

Even Giovanni Pietro Bellori, who included Agostino Carracci in his selective collection of biographies of artists (Vite de' pittori, scultori e architetti moderni, 1672), described his activity as a painter, with the sole exception of the Communion of Saint Jerome, a work that he praises, almost entirely limited to the role of supporting his younger brother Annibale, and reproaches him for having dedicated too much of his work to graphic production.

The modern critical evaluation of the painter Agostino Carracci probably still suffers from the negative legacies of the past. The fact that there is still only one important monograph dedicated to him published (Stephen E. Ostrow, from the United States, 1966, never translated into Italian), and that an individual exhibition on this artist has yet to be held, are probably significant factors that show that he remains an underrated artist.

However, there have been a positive critical reevaluation of the painter, since there is now a better awareness of his artistic role, alongside his more famous relatives, and the knowledge of his personal work is now greater.

Works
Oil on canvas unless otherwise noted

 * 1573 – Pietà (Muscarelle Museum of Art, Williamsburg, Virginia )
 * 1586 – Madonna and Child with Saints (Galleria nazionale di Parma)
 * c. 1586 – Lamentation or Pietà (Hermitage, St. Petersburg )
 * c. 1589–1595 – Reciprico Amore (engraving, Baltimore Museum of Art )
 * c. 1590 – Annunciation (Musée du Louvre, Paris )
 * 1590–1595 – Portrait of a Woman as Judith (private collection)
 * c. 1592–1593 – Assumption (Ss. Salvatore church, Bologna)
 * 1592–1597 – The Last Communion of Saint Jerome (Pinacoteca Nazionale di Bologna)
 * c. 1595 – Head of a Faun in a Concave (drawing in roundel, National Gallery of Art, Washington DC)
 * 1598–1600 – Triple Portrait of Arrigo, Pietro and Amon (National Museum of Capodimonte, Naples)

Fresco collaborations with Annibale and Ludovico

 * Life of Aeneas (Palazzo Fava, Bologna)
 * Lives of Jason and Medea (Palazzo Fava, Bologna)
 * Scenes from the Foundation of Rome (Palazzo Magnani, Bologna)
 * Life of Hercules (Palazzo Sampieri Talon, Bologna)

Undated

 * The Penitent Magdalen (private collection)
 * Carracci's erotic work (prints)

title: Agostino Carracci


text:
Adenylyl cyclase

Adenylate cyclase (EC 4.6.1.1, also commonly known as adenyl cyclase and adenylyl cyclase, abbreviated AC) is an enzyme with systematic name ATP diphosphate-lyase (cyclizing; 3′,5′-cyclic-AMP-forming). It catalyzes the following reaction:

 * ATP = 3′,5′-cyclic AMP + diphosphate

It has key regulatory roles in essentially all cells. It is the most polyphyletic known enzyme: six distinct classes have been described, all catalyzing the same reaction but representing unrelated gene families with no known sequence or structural homology. The best known class of adenylyl cyclases is class III or AC-III (Roman numerals are used for classes). AC-III occurs widely in eukaryotes and has important roles in many human tissues.

All classes of adenylyl cyclase catalyse the conversion of adenosine triphosphate (ATP) to 3',5'-cyclic AMP (cAMP) and pyrophosphate. Magnesium ions are generally required and appear to be closely involved in the enzymatic mechanism. The cAMP produced by AC then serves as a regulatory signal via specific cAMP-binding proteins, either transcription factors, enzymes (e.g., cAMP-dependent kinases), or ion transporters.

Class I
The first class of adenylyl cyclases occur in many bacteria including E. coli (as CyaA [unrelated to the Class II enzyme]). This was the first class of AC to be characterized. It was observed that E. coli deprived of glucose produce cAMP that serves as an internal signal to activate expression of genes for importing and metabolizing other sugars. cAMP exerts this effect by binding the transcription factor CRP, also known as CAP. Class I AC's are large cytosolic enzymes (~100 kDa) with a large regulatory domain (~50 kDa) that indirectly senses glucose levels. , no crystal structure is available for class I AC.

Some indirect structural information is available for this class. It is known that the N-terminal half is the catalytic portion, and that it requires two Mg2+ ions. S103, S113, D114, D116 and W118 are the five absolutely essential residues. The class I catalytic domain belongs to the same superfamily  as the palm domain of DNA polymerase beta. Aligning its sequence onto the structure onto a related archaeal CCA tRNA nucleotidyltransferase allows for assignment of the residues to specific functions: γ-phosphate binding, structural stabilization, DxD motif for metal ion binding, and finally ribose binding.

Class II
These adenylyl cyclases are toxins secreted by pathogenic bacteria such as Bacillus anthracis, Bordetella pertussis, Pseudomonas aeruginosa, and Vibrio vulnificus during infections. These bacteria also secrete proteins that enable the AC-II to enter host cells, where the exogenous AC activity undermines normal cellular processes. The genes for Class II ACs are known as cyaA, one of which is anthrax toxin. Several crystal structures are known for AC-II enzymes.

Class III
These adenylyl cyclases are the most familiar based on extensive study due to their important roles in human health. They are also found in some bacteria, notably Mycobacterium tuberculosis where they appear to have a key role in pathogenesis. Most AC-III's are integral membrane proteins involved in transducing extracellular signals into intracellular responses. A Nobel Prize was awarded to Earl Sutherland in 1971 for discovering the key role of AC-III in human liver, where adrenaline indirectly stimulates AC to mobilize stored energy in the "fight or flight" response. The effect of adrenaline is via a G protein signaling cascade, which transmits chemical signals from outside the cell across the membrane to the inside of the cell (cytoplasm). The outside signal (in this case, adrenaline) binds to a receptor, which transmits a signal to the G protein, which transmits a signal to adenylyl cyclase, which transmits a signal by converting adenosine triphosphate to cyclic adenosine monophosphate (cAMP). cAMP is known as a second messenger.

Cyclic AMP is an important molecule in eukaryotic signal transduction, a so-called second messenger. Adenylyl cyclases are often activated or inhibited by G proteins, which are coupled to membrane receptors and thus can respond to hormonal or other stimuli. Following activation of adenylyl cyclase, the resulting cAMP acts as a second messenger by interacting with and regulating other proteins such as protein kinase A and cyclic nucleotide-gated ion channels.

Photoactivated adenylyl cyclase (PAC) was discovered in Euglena gracilis and can be expressed in other organisms through genetic manipulation. Shining blue light on a cell containing PAC activates it and abruptly increases the rate of conversion of ATP to cAMP. This is a useful technique for researchers in neuroscience because it allows them to quickly increase the intracellular cAMP levels in particular neurons, and to study the effect of that increase in neural activity on the behavior of the organism. A green-light activated rhodopsin adenylyl cyclase (CaRhAC) has recently been engineered by modifying the nucleotide binding pocket of rhodopsin guanylyl cyclase.

Structure
Most class III adenylyl cyclases are transmembrane proteins with 12 transmembrane segments. The protein is organized with 6 transmembrane segments, then the C1 cytoplasmic domain, then another 6 membrane segments, and then a second cytoplasmic domain called C2. The important parts for function are the N-terminus and the C1 and C2 regions. The C1a and C2a subdomains are homologous and form an intramolecular 'dimer' that forms the active site. In Mycobacterium tuberculosis and many other bacterial cases, the AC-III polypeptide is only half as long, comprising one 6-transmembrane domain followed by a cytoplasmic domain, but two of these form a functional homodimer that resembles the mammalian architecture with two active sites. In non-animal class III ACs, the catalytic cytoplasmic domain is seen associated with other (not necessarily transmembrane) domains.

Class III adenylyl cyclase domains can be further divided into four subfamilies, termed class IIIa through IIId. Animal membrane-bound ACs belong to class IIIa.

Mechanism
The reaction happens with two metal cofactors (Mg or Mn) coordinated to the two aspartate residues on C1. They perform a nucleophilic attack of the 3'-OH group of the ribose on the α-phosphoryl group of ATP. The two lysine and aspartate residues on C2 selects ATP over GTP for the substrate, so that the enzyme is not a guanylyl cyclase. A pair of arginine and asparagine residues on C2 stabilizes the transition state. In many proteins, these residues are nevertheless mutated while retaining the adenylyl cyclase activity.

Types
There are ten known isoforms of adenylyl cyclases in mammals: • ADCY1

• ADCY2

• ADCY3

• ADCY4

• ADCY5

• ADCY6

• ADCY7

• ADCY8

• ADCY9

• ADCY10 These are also sometimes called simply AC1, AC2, etc., and, somewhat confusingly, sometimes Roman numerals are used for these isoforms that all belong to the overall AC class III. They differ mainly in how they are regulated, and are differentially expressed in various tissues throughout mammalian development.

Regulation
Adenylyl cyclase is regulated by G proteins, which can be found in the monomeric form or the heterotrimeric form, consisting of three subunits. Adenylyl cyclase activity is controlled by heterotrimeric G proteins. The inactive or inhibitory form exists when the complex consists of alpha, beta, and gamma subunits, with GDP bound to the alpha subunit. In order to become active, a ligand must bind to the receptor and cause a conformational change. This conformational change causes the alpha subunit to dissociate from the complex and become bound to GTP. This G-alpha-GTP complex then binds to adenylyl cyclase and causes activation and the release of cAMP. Since a good signal requires the help of enzymes, which turn on and off signals quickly, there must also be a mechanism in which adenylyl cyclase deactivates and inhibits cAMP. The deactivation of the active G-alpha-GTP complex is accomplished rapidly by GTP hydrolysis due to the reaction being catalyzed by the intrinsic enzymatic activity of GTPase located in the alpha subunit. It is also regulated by forskolin, as well as other isoform-specific effectors:

 * Isoforms I, III, and VIII are also stimulated by Ca2+/calmodulin.
 * Isoforms V and VI are inhibited by Ca2+ in a calmodulin-independent manner.
 * Isoforms II, IV and IX are stimulated by alpha subunit of the G protein.
 * Isoforms I, V and VI are most clearly inhibited by Gi, while other isoforms show less dual regulation by the inhibitory G protein.
 * Soluble AC (sAC) is not a transmembrane form and is not regulated by G proteins or forskolin, instead acts as a bicarbonate/pH sensor. It is anchored at various locations within the cell and, with phosphodiesterases, forms local cAMP signalling domains.

In neurons, calcium-sensitive adenylyl cyclases are located next to calcium ion channels for faster reaction to Ca2+ influx; they are suspected of playing an important role in learning processes. This is supported by the fact that adenylyl cyclases are coincidence detectors, meaning that they are activated only by several different signals occurring together. In peripheral cells and tissues adenylyl cyclases appear to form molecular complexes with specific receptors and other signaling proteins in an isoform-specific manner.

Function
Individual transmembrane adenylyl cyclase isoforms have been linked to numerous physiological functions. Soluble adenylyl cyclase (sAC, AC10) has a critical role in sperm motility. Adenylyl cyclase has been implicated in memory formation, functioning as a coincidence detector.

Class IV
AC-IV was first reported in the bacterium Aeromonas hydrophila, and the structure of the AC-IV from Yersinia pestis has been reported. These are the smallest of the AC enzyme classes; the AC-IV (CyaB) from Yersinia is a dimer of 19 kDa subunits with no known regulatory components. AC-IV forms a superfamily with mammalian thiamine-triphosphatase called CYTH (CyaB, thiamine triphosphatase).

Classes V and VI
These forms of AC have been reported in specific bacteria (Prevotella ruminicola and Rhizobium etli, respectively) and have not been extensively characterized. There are a few extra members (~400 in Pfam) known to be in class VI. Class VI enzymes possess a catalytic core similar to the one in Class III.

title: Adenylyl cyclase