Cebola

  • Mensagens: 413

nunopinheiro

  • Mensagens: 4461
Parvoíce total a teimosia de Boeing e FAA em não fazer o grounding logo no início deu nisto...

Spark

  • Mensagens: 5763
Espera... quer dizer então que meter o Max no chão foi a melhor coisa que se podia ter feito?

Didn't see that coming...


A internet nos dias de hoje são 2 veículos: o hypetrain e o hatewagon.
ALL ABOARD!!!

Wazkovzky

  • Mensagens: 34

oliveco

  • Mensagens: 69
    • Vivo atualmente em Luanda. E gosto de seguir assuntos de aviação

Caravelle

  • Mensagens: 264
Pagas amendoins...

Bons voos.
Daily flights to
EUROPE - AFRICA - AMERICAS

nunopinheiro

  • Mensagens: 4461
Não sei se partilham a minha experiência, mas a qualidade do software outsourcing para a India deixa muito muito a desejar...
« Última modificação: 30 de Junho 2019, 00:33:19 por nunopinheiro »


Caravelle

  • Mensagens: 264
Não programo (embora tenha aprendido asm de 8085 no secundário - e gostava muito de programar coisas em baixo nível), mas pelos contos do thedailywtf, a coisa não me parece famosa. Não é só especificar com altíssima precisão. Também é preciso implementar da mesma forma.

Citação
(...) it was controversial because it was far less efficient than Boeing engineers just writing the code,” Rabin said. Frequently, he recalled, “it took many rounds going back and forth because the code was not done correctly.”

Citação
“We did have our challenges with the India team,” he said. “They met the requirements, per se, but you could do it better.”

Existem maneiras de se implementar instruções em baixo nível que podem ser equivalentes, mas gastar mais ciclos de clock ou empatar mais memória ou implicar operações auxiliares desnecessárias. Essas implementações podem tornar a programação ineficiente sem serem incorrectas e desbaratar recursos sem necessidade.

Citação
The company’s shares fell this week after the regulator found a further problem with a computer chip that experienced a lag in emergency response when it was overwhelmed with data.

O excesso de processamento do computador que torna a resposta lenta - a publicação não refere qual a peça que causa o constrangimento - poderia e deveria ter sido verificado pelo integrador do software e deveria também ser um caso de teste do sistema, o que poderia ser corrigido por uma redistribuição da alocação de recursos no computador, diminuição da frequência de amostragem para certos parâmetros, aumento de memória ou capacidade de processamento ou, em último caso, um redesign do sistema.

Citação
Multiple investigations – including a Justice Department criminal probe – are trying to unravel how and when critical decisions were made about the Max’s software. During the crashes of Lion Air and Ethiopian Airlines planes that killed 346 people, investigators suspect, the MCAS system pushed the planes into uncontrollable dives because of bad data from a single sensor.

That design violated basic principles of redundancy for generations of Boeing engineers, and the company apparently never tested to see how the software would respond, Lemme said. “It was a stunning fail,” he said. “A lot of people should have thought of this problem – not one person – and asked about it.”

Boeing also has disclosed that it learned soon after Max deliveries began in 2017 that a warning light that might have alerted crews to the issue with the sensor wasn’t installed correctly in the flight-display software. A Boeing statement in May, explaining why the company didn’t inform regulators at the time, said engineers had determined it wasn’t a safety issue.

E a minha opinião sobre isso já a dei mais atrás. Más decisões técnicas tomadas levianamente (ou com falta de consciência - eventualmente também devido ao outsourcing) ou ainda com receio de perder o emprego. Existem sérios problemas quando as companhias são excessivamente geridas por contabilistas e pouco por técnicos. Tem que haver uma mistura saudável que garanta as boas contas e as regras da arte, nos domínios em que interessa.

Evidentemente poderá pender mais para um lado ou outro e assim será dependendo da maturidade dos produtos e das especificidades do negócio.


Bons voos.
Daily flights to
EUROPE - AFRICA - AMERICAS

nunopinheiro

  • Mensagens: 4461
Não é só na Boeing, já perdi a conta ao número de vezes que fomos chamados para resolver problemas de grandes companhias com o outsourcing na Índia...

As vezes o problema nem é bem a falta de qualidade dos eng. Indianos, mas o facto de as grandes companhias contratarem autocarros de eng. Sem grandes metodologias de desenvolvimento e sem hownership do lado de lá dos projectos passam a vida a empurrar com a barriga os problemas.
O resultado final é sempre o mesmo, perdemos 3 vezes mais tempo porque temos de escrever o código  gerir equipas disfuncionais, e formar gente que não estava realmente preparada.

Também há problemas de comunicação graves causados por culturas diferentes.

CS-TTK

  • Moderador
  • Mensagens: 1471
Eu sou de opinião que o desenvolvimento de softwares críticos deste tipo nunca deve ser subcontratado.

Primeiro porque pode originar uma falha de segurança, segundo porque se esta pratica se torna recorrente a empresa perde know how. Nunca pensei que tal coisa fosse acontecer na Boeing (diria o mesmo para Airbus, Embraer, etc)

mukanico

  • Mensagens: 8
Eu sou de opinião que o desenvolvimento de softwares críticos deste tipo nunca deve ser subcontratado.

Primeiro porque pode originar uma falha de segurança, segundo porque se esta pratica se torna recorrente a empresa perde know how. Nunca pensei que tal coisa fosse acontecer na Boeing (diria o mesmo para Airbus, Embraer, etc)

Podes continuar a lista, PW, GE, Rolls-Royce, têm todas instalações ao lado umas das outras em Bangalore. Posso falar de experiência própria, quem apresenta aos accionistas o valor hora da engenharia não faz ideia da tortura que é receber o trabalho que vem do outsourcing e faze-lo parecer alguma coisa de jeito!

pedferre

  • Mensagens: 397
Desculpem a minha opinião mas vou bater na mesma tecla, não imagino a Airbus a fazer borradas destas, tem quanto a mim a vantagem de ter capital estatal (espanhol, alemão e francês) e não me parece apenas uma empresa financeira, mas com mais equilibrio (devido aos estados também estarem diretamente envolvidos nos destinos).
Claro que isso também causa os seus vicios (na minha opinião), torna-se uma empresa mais politizada (como a TAP por exemplo), mas menos susceptivel a estes laxismos de segurança, de olhar mais exclusivamente para a parte financeira e para os dividendos.
« Última modificação: 01 de Julho 2019, 10:51:45 por pedferre »


heartness

  • Mensagens: 81
Desculpem a minha opinião mas vou bater na mesma tecla, não imagino a Airbus a fazer borradas destas, tem quanto a mim a vantagem de ter capital estatal (espanhol, alemão e francês) e não me parece apenas uma empresa financeira, mas com mais equilibrio (devido aos estados também estarem diretamente envolvidos nos destinos).
Claro que isso também causa os seus vicios (na minha opinião), torna-se uma empresa mais politizada (como a TAP por exemplo), mas menos susceptivel a estes laxismos de segurança.

Air France AF447

toto1100

  • Mensagens: 4015
Desculpem a minha opinião mas vou bater na mesma tecla, não imagino a Airbus a fazer borradas destas, tem quanto a mim a vantagem de ter capital estatal (espanhol, alemão e francês) e não me parece apenas uma empresa financeira, mas com mais equilibrio (devido aos estados também estarem diretamente envolvidos nos destinos).
Claro que isso também causa os seus vicios (na minha opinião), torna-se uma empresa mais politizada (como a TAP por exemplo), mas menos susceptivel a estes laxismos de segurança, de olhar mais exclusivamente para a parte financeira e para os dividendos.

Ja estavas errado em Abril e continuas errado: https://aviacao.pt/index.php?topic=5162.840

pedferre

  • Mensagens: 397
Desculpem a minha opinião mas vou bater na mesma tecla, não imagino a Airbus a fazer borradas destas, tem quanto a mim a vantagem de ter capital estatal (espanhol, alemão e francês) e não me parece apenas uma empresa financeira, mas com mais equilibrio (devido aos estados também estarem diretamente envolvidos nos destinos).
Claro que isso também causa os seus vicios (na minha opinião), torna-se uma empresa mais politizada (como a TAP por exemplo), mas menos susceptivel a estes laxismos de segurança.

Air France AF447
Não é comparável com este caso, ai os pilotos tiveram uma boa dose de culpa... e os tubos pilot já estavam a ser substituidos porque o problema de congelamento já tinha sido detetado, e a airbus já tinha dado um indicação para as companhias aéreas procederam à substituição dos mesmos ainda antes do acidente.
Já tinha havido vários casos destes (congelamento), em que mesmo com talvez um software confuso os pilotos não fizeram aquela borrada de perder o controlo espacial... se o avião estava a descer/subir, etc.
E outras companhias aéreas (como a Lufthansa) fizeram um pequeno desvio para não se meterem mesmo no meio de uma mega-tempestade... mas isso também é culpa da Airbus de certeza, foi a Airbus que disse para os pilotos passarem mesmo no meio da tempestade...
Mas pronto eu já estou habituado a usarem sempre a mesma "carta" de que a Airbus é a responsável por esse acidente... quando nem sequer era ela a fazer os tubos pilot, penso que era a Thales ou algo.

P.S: Já agora não me lembro de funcionários da Airbus virem para os jornais dizerem que tinham de andar a martelar os narizes dos aviões porque as peças estavam mal feitas e não encaixavam... mas da Boeing lembro-me... aqui a uns anitos de virem para os jornais falarem dessas práticas da empresa... :)

https://www.aljazeera.com/programmes/peopleandpower/2010/12/20101214104637901849.html

For more than a year Al Jazeera has been investigating allegations - made in US Federal Court proceedings - that between 1996 and 2004 ill-fitting, illegal and dangerous parts were assembled on to many of the most commonly-used passenger planes in the world today.

Three generations of Gigi Prewitt's family had worked for the Boeing company
The allegations concern the Boeing Company - the most respected name in international aviation and the world's second-largest commercial aircraft manufacturer.

The claims were made by then employees of Boeing in Wichita, Kansas who were working on a radically new passenger plane - the 737 Next Generation (NG).

Boeing had produced 737s since the mid-1960s, and the 737 series is the world's most popular short and medium-haul passenger aircraft. It is estimated that, throughout the world, a 737 takes off or lands every five seconds.

But by the mid-1990s Boeing had begun to lose market share to its European rival, Airbus. To regain its pre-eminent position, Boeing decided to build an entirely new version of the 737 - the Next Generation.

Earlier models were built by hand: as a result the dimensions or accuracy of each individual part would often be marginally different, resulting in the need for assembly workers to pack out gaps with "shims" or fillers. These added to the overall weight of an aircraft, making it more expensive to fly.

Parts for the new 737NG plane were to be designed, manufactured and built by a revolutionary new computerised process called ATA. Not only would this ensure that each individual part was identical, but that each would be precise to within 3000ths of an inch.

According to leading aircraft engineer, Dr Michael Dreikorn: "This ATA was designed so that the tolerances on putting the aeroplane together would be so tight that the aircraft would have higher strength and reliability. And in response to that, this aeroplane was certified to have higher gross weight and be able to operate at higher altitudes."

Boeing through and through

Every new aircraft design has to be assessed and approved by a regulatory authority: for American manufacturers like Boeing, the regulator is the Federal Aviation Administration (FAA).

Boeing submitted all its engineering drawings and data to the FAA and, in 1996, the FAA gave Boeing the thumbs up. It issued what the industry calls a Type Design Certificate - essentially a licence to manufacture the aircraft provided to all the specifications laid out in the engineering data which had been submitted and approved.

Boeing planned to assemble the 737NG fuselages in Wichita. But it subcontracted the manufacture of some key parts to a company called AHF Ducommun, based in Gardena, California.

Gigi Prewitt was Boeing through and through. Her family had worked for Boeing in Wichita for three generations and she was excited when she was asked to look after buying key parts for the 737NG.   But within a short space of time, she noticed something was wrong.

"The minute that I took the desk of buying 737NG parts I had shop personnel coming to me talking to me about the problems and the issues they were having with the parts not being manufactured accurately. [They reported] Shy-edge margins and were, out of contour, parts not fitting correctly ..." Prewitt says.
'Catastrophic failure'

The parts in question were some of the most crucial elements of an aircraft fuselage - parts known as "chords" and "bear-straps".


Lawyer Bill Skepnek has become intimately acquainted with almost every nook and cranny of the 737NG
An aircraft fuselage is like a giant tube. That tube is made up of interlocking semi-circular pieces of metal - these are the "chords" and put together they form the 'frame' around which every other part of the airframe is built ... and on which the external 'skin' is assembled.

Exit doorways and cargo hatches are potential weak points in this fuselage: to strengthen them, huge re-enforcing sheets are assembled around the holes - these are the "bear-straps".

So vital are these parts to the safety of an aircraft, that Boeing's own 737NG Structural Repair Manual - obtained by Al Jazeera in the course of its investigation - lists them as "Primary Structural Elements" and warns: "The failure of PSE's could result in the catastrophic failure of the airplane."

According to lawyer Bill Skepnek - who for the last six years has become intimately acquainted with almost every nook and cranny of the 737NG design - when Boeing talks of the potential for these parts to cause  "catastrophic failure", it means exactly what it says.

"These are the parts of airplanes that, if they fail, we can have a decompression at altitude or we can have a rupture in the vessel, in the fuselage vessel of the aircraft. And as long as we can make that [fuselage] hold together we can keep the passengers safe."

But in Wichita, Gigi Prewitt was not the only Boeing employee coming across reports of ill-fitting and badly made parts. In another building on Boeing's vast factory site, Taylor Smith was getting very similar-sounding complaints.

"One of the shop managers sent me an email saying they were having problems with the fail-safe cords which are the long ribs that go all the way along the aircraft [...] They were telling me that from the beginning of the 1996 timeframe when they started manufacturing these parts, that they were coming in with shy edge margins, they were out of contour," Smith says.

Boeing's internal documents, which Al Jazeera obtained, give a snap-shot of the scale of the problem.

Part out of contour: quantity 1 … Part width – oversize: Quantity 4 … Material thin: Quantity 6… Part undercut: Quantity 26 … Hole mis-located: Quantity 17….

They also show the source of the problem: AHF Ducommun.

'Putting our foot down'

But, according to Gigi Prewitt and Taylor Smith, Boeing rejected only a handful of these defective parts.  The rest were assembled on to 737NG aircraft.

"We were putting our foot down and not going to participate in allowing non-conforming parts to come in and be put on planes. But one of the managers was very upset in procurement and wrote an email and said 'this is stupid - there are already 300 of them out there on planes; why would we scrap them now?' So they used them, they put them on planes," Prewitt says.

Finally, in early 2000, Boeing sent Prewitt, Smith and 12 other specialist employees to conduct an audit of the Ducommun manufacturing plant. What they found - and documented with photographs as well as reports - shocked them profoundly.

Instead of being manufactured by the approved computerised process, Ducommun employees were cutting the parts by hand - literally using a felt-tipped pen to mark out the shape and then cutting the metal with a hand-cutter.

Not only did this result in parts which could never meet the mandated 3000ths of an inch accuracy - but the Boeing team realised it violated the official type design: any aircraft with these parts on them would be legally "unairworthy" - and therefore not allowed to fly.

But there was worse to come: every part in the production process has to be signed off at each stage of its manufacture on a document called a "shop traveller". This records that each individual stage of manufacture has been carried out in accordance with the type design.

The Boeing team discovered that Ducommun had apparently falsified these records: it had two sets of "books" - the official one recording that each part had been made by the computerised process and a second set recording the actual, handforming process which had really been used.

What that meant, in the eyes of the Boeing team, was that every single chord and bear strap manufactured by Ducommun had to be viewed as unlawful.

Mystery

Initially Boeing itself seems to have agreed: Al Jazeera obtained an internal draft memorandum prepared by senior Boeing officials in August 2000 and intended to be sent to the company's top management. It warned:


Taylor Smith says: 'We met with the government and told them our story'
"The severity of these conditions is documented via photographs and poses a quality risk to the production of quality airplane parts...

"Misrepresentation of the manufacturing process jeopardises the integrity of airplane parts ...

"... this situation cannot be ignored ...

"... the integrity of AHF-Ducommun as a partnered supplier places the Boeing Company at risk.

"Immediately cease all new business activity with AHF-Ducommun and consider disengagement ..."

What happened to this memorandum is a mystery: today, Boeing refuses to discuss it - or what actions it took on the recommendations.

But Gigi Prewitt and Taylor Smith say that ill-fitting and out of contour parts continued to arrive from AHF Ducommun - and that assembly workers in Wichita took dangerous short-cuts to get them to fit.

Some parts were so badly out of shape that they had to be beaten on to the airframe with hammers - a process which builds in potentially lethal pre-stress.

The FAA had given Boeing "delegated authority" to police itself on matters like this - provided it reported problems voluntarily.

Turning whistle-blower

Both Smith and Prewitt wanted to come clean to the FAA, but claim that Boeing management threatened to sue them if they did so.

Reluctantly, they turned whistle-blower - taking their concerns to the US Justice Department, which, under American law, is responsible for protecting whistle-blowers.

According to Taylor Smith: "We actually met with the government and told them our story - they had the same reaction most people have when they first hear the story - we will protect you, we will not let you be retaliated against, we will keep you safe."

The Department of Justice ordered two investigations - one by the FAA and, because Boeing had sold some 737NGs to the military, one by the Defence Criminal Investigative Service.

But the whistle-blowers have been dismayed by these investigations. Al Jazeera obtained a copy of the FAA investigation - which the administration redacted. The only publicly-viewable "investigative actions" appear to be that the FAA looked up Ducommun's address and visited its website.

The DCIS report was another matter altogether. Again, Al Jazeera obtained a copy of its investigative files - and these appeared to confirm some of the allegations about the manufacture and the safety of the Ducommun parts.

Yet the Department of Justice finally ordered that both investigations be closed without action.

The Boeing whistle-blowers lost their jobs during this period. For the past six years they and their lawyer, Bill Skepnek, have spent their own money trying to bring a legal action against Boeing and Ducommon on behalf of the American public.

They are supported by highly-respected aircraft industry specialists and engineers like Dr Michael Dreikorn, a former FAA official.

"It is getting to the point where there is going to be a catastrophic failure of a 737NG. We do not know when that hour is going to hit but we know it is going to happen," Dreikorn says.

"I am very seriously concerned about a catastrophic cabin failure at altitude. And I think it would be a 737NG that will lose its ability to stay together and unfortunately will be a smoking hole in the ground."

But the story of what has happened during this legal battle reads like the plot of a John Grisham novel.  And it has left the whistle-blowers convinced that today they are fighting not simply one of the world's most powerful companies - but the power of the US government itself.

As Taylor Smith tells the Al Jazeera filmmakers: "It's a tough road if you take a stand against large companies and the government and it's had a personal effect on me ... and my family. It's a heavy burden to bear. But my greatest fear is that the aircraft will start having big issues and there will start being crashes and there will be hundreds of people that are being killed and I'll wonder whether I did enough."
« Última modificação: 01 de Julho 2019, 12:21:26 por pedferre »


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