Precipitato un B737 Max 8 di Ethiopian

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mattaus313
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Re: Precipitato un B737 Max 8 di Ethiopian

Messaggio da leggereda mattaus313 » mer 26 giu 2019, 23:56:14

Mi chiedo se qualcuno ad Everett non si stia chiedendo se non fosse il caso di buttare nel cesso tutto il programma e ripartire da zero.
"Because you needed a lot of capital in an airline, you needed to be where the financial markets were, and obviously that's New York"

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Re: Precipitato un B737 Max 8 di Ethiopian

Messaggio da leggereda I-Alex » gio 27 giu 2019, 07:37:23

La vedo male e lunga per i MAX

Riporto per intero la notizia postata sopra perché se confermato è un passaggio importante per la (non) ripresa dei B737 Max

https://www.reuters.com/article/us-ethi ... SKCN1TR30J


BUSINESS NEWS

JUNE 26, 2019 / 10:01 PM / UPDATED 4 HOURS AGO

U.S. regulator cites new flaw on grounded Boeing 737 MAX

David Shepardson, Eric M. Johnson

WASHINGTON/SEATTLE (Reuters) - The U.S. Federal Aviation Administration has identified a new risk that Boeing Co must address on its 737 MAX before the grounded jet can return to service, the agency said on Wednesday.

The risk was discovered during a simulator test last week and it is not yet clear if the issue can be addressed with a software upgrade or will require a more complex hardware fix, sources with knowledge of the matter told Reuters.


The FAA did not elaborate on the latest setback for Boeing, which has been working to get its best-selling airplane back in the air following a worldwide grounding in March in the wake of two deadly crashes within five months.
The new issue means Boeing will not conduct a certification test flight until July 8 in a best-case scenario, the sources said, but one source cautioned it could face further delays beyond that. The FAA will spend at least two to three weeks reviewing the results before deciding whether to return the plane to service, the people said.


Last month, FAA representatives told members of the aviation industry that approval of the 737 MAX jets could happen as early as late June.
The world’s largest planemaker has been working on the upgrade for a stall-prevention system known as MCAS since a Lion Air crash in Indonesia in October, when pilots were believed to have lost a tug of war with software that repeatedly pushed the nose down.
A second deadly crash in March in Ethiopia also involved MCAS. The two accidents killed a total of 346 people.


“On the most recent issue, the FAA’s process is designed to discover and highlight potential risks. The FAA recently found a potential risk that Boeing must mitigate,” the FAA said in the statement emailed to Reuters. “The FAA will lift the aircraft’s prohibition order when we deem it is safe to do so.”
Boeing said in a securities filing late on Wednesday that the FAA has asked it to address through software changes a specific flight condition not covered in the company’s already-unveiled software changes.
The U.S. planemaker also said it agreed with the FAA’s decision and request, and was working on a fix to address the problem.

FILE PHOTO: Employees walk by the end of a 737 Max aircraft at the Boeing factory in Renton, Washington, U.S., March 27, 2019. REUTERS/Lindsey Wasson/File Photo

“Boeing will not offer the 737 MAX for certification by the FAA until we have satisfied all requirements for certification of the MAX and its safe return to service,” Boeing wrote in the filing.

INTENSE SCRUTINY

Boeing’s aircraft are being subjected to intense scrutiny and testing designed to catch flaws even after a years-long certification process.



Two people briefed on the matter told Reuters that an FAA test pilot during a simulator test last week was running scenarios seeking to intentionally activate the MCAS stall-prevention system. During one activation it took an extended period to recover the stabilizer trim system that is used to control the aircraft, the people said.
It was not clear if the situation that resulted in an uncommanded dive can be addressed with a software update or if it is a microprocessor issue that will require a hardware replacement.
In a separate statement, Boeing said addressing the new problem would remove a potential source of uncommanded movement by the plane’s stabilizer.
A hardware fix could add new delays to the plane’s return to service.
The FAA also said on Wednesday that it continues “to evaluate Boeing’s software modification to the MCAS and we are still developing necessary training requirements. We also are responding to recommendations received from the Technical Advisory Board. The TAB is an independent review panel we have asked to review our work regarding 737 Max return to service.”
American Airlines Group Inc and Southwest Airlines Co earlier canceled flights through early September as a result of the grounding. On Wednesday, United Airlines said it also was removing MAX flights from its schedule through Sept. 3.

Reporting by David Shepardson in Washington; Additional reporting by Eric M. Johnson in Seattle; Writing by Tracy Rucinski; Editing by Phil Berlowitz and Matthew Lewis
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robygun
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Re: Precipitato un B737 Max 8 di Ethiopian

Messaggio da leggereda robygun » gio 27 giu 2019, 10:14:06

mattaus313 ha scritto:Mi chiedo se qualcuno ad Everett non si stia chiedendo se non fosse il caso di buttare nel cesso tutto il programma e ripartire da zero.
Vorrebbe dire uscire dal mercato del corto raggio per molto tempo..

Un nuovo modello non lo sviluppi in tempi brevi, soprattutto se parti da zero..

kco
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Re: Precipitato un B737 Max 8 di Ethiopian

Messaggio da leggereda kco » gio 27 giu 2019, 11:13:06

https://www.flightglobal.com/news/artic ... f214931410

La gola profonda ha parlato anche con Flight International

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kco
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Re: Precipitato un B737 Max 8 di Ethiopian

Messaggio da leggereda kco » sab 29 giu 2019, 14:55:23

Da copia di flight international in mio possesso


Boeing's hopes of a rapid return to service of the 737 Max have been dealt a setback after the US Federal Aviation Administration (FAA) discovered a new flaw with the re-engined narrowbody's flight-control software.

Pilots working for the agency uncovered the latest issue whilst performing a recent round of simulator flights to assess changes to the Max's systems.

"During simulator testing at Boeing, FAA test pilots discovered an issue that affected their ability to quickly and easily follow the required recovery procedures for runaway stabiliser trim," a source familiar with the FAA's 737 Max evaluation tells FlightGlobal. "The issue was traced to how data is being processed by the flight computer."

The runaway stabiliser procedure is the method Boeing says pilots should use if there is erroneous activation of the aircraft's Maneuvering Characteristics Augmentation System (MCAS) - the software implicated in two fatal crashes of the type.

Boeing says the safety of its aircraft remains the company's "highest priority", adding: "We are working closely with the FAA to safely return the Max to service."

The FAA says the newly-disclosed problem is "a potential risk that Boeing must mitigate" and insists it will only return the narrowbody to service "when we deem it is safe to do so". There is no "prescribed timeline" to lift the grounding, it adds.

"We continue to evaluate Boeing's software modification to the MCAS and we are still developing necessary training requirements," the FAA adds.

The FAA is also addressing recommendations it received from a "technical advisory board" convened to review its previous 737 Max work, says the agency.

Boeing adds that the FAA "identified an additional requirement that it has asked the company to address through the software changes that the company has been developing for the past eight months".

"Boeing agrees with the FAA's decision and request, and is working on the required software," the company adds. "Addressing this condition will reduce pilot workload by accounting for a potential source of uncommanded stabiliser motion."

Regulators worldwide grounded the 737 Max in March following a pair of crashes, five months apart, which killed a combined 346 people.



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malpensante
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Re: Precipitato un B737 Max 8 di Ethiopian

Messaggio da leggereda malpensante » sab 29 giu 2019, 15:07:40

Muilenburg e i suoi sono fortunati a lavorare per Boeing oggi anziché per Mitsubishi negli anni ‘40.
And Malpensa is going to be our Hub

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mattaus313
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Re: Precipitato un B737 Max 8 di Ethiopian

Messaggio da leggereda mattaus313 » sab 29 giu 2019, 22:45:23

Boeing's 737 Max Software Outsourced to $9-an-Hour Engineers


https://www.bloomberg.com/news/articles ... r-business
"Because you needed a lot of capital in an airline, you needed to be where the financial markets were, and obviously that's New York"

easyMXP
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Re: Precipitato un B737 Max 8 di Ethiopian

Messaggio da leggereda easyMXP » sab 29 giu 2019, 23:04:48

mattaus313 ha scritto:
Boeing's 737 Max Software Outsourced to $9-an-Hour Engineers


https://www.bloomberg.com/news/articles ... r-business

Articolo fuorviante.
I problemi con MCAS derivano da una serie scellerata di decisioni di safety e design, tutte compiute da americanissimi dipendenti Boeing di lungo corso.
Quelli che hanno scritto il SW (di MCAS e del resto) hanno semplicemente messo in pratica le specifiche preparate da Boeing, indiani o no che siano.
Che poi ci sia la moda di appaltare il lavoro agli indiani, che lavorano male ma costano così poco che anche se rifanno il lavoro 10 volte alla fine costano meno che a farlo direttamente bene, è un altro discorso.

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mattaus313
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Re: Precipitato un B737 Max 8 di Ethiopian

Messaggio da leggereda mattaus313 » sab 29 giu 2019, 23:20:56

Ma la parte che più mi ha colpito è il fatto che Boeing abbia esternalizzato (che poi magari è prassi comune è una cosa a cui semplicemente non ho mai neanche pensato) la "produzione di un componente" così importante e per certi versi strategico di un proprio prodotto.

Avrei giurato senza dubbio che venisse fatto tutto in casa e neanche tanto per ragioni di costo.
"Because you needed a lot of capital in an airline, you needed to be where the financial markets were, and obviously that's New York"

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Re: Precipitato un B737 Max 8 di Ethiopian

Messaggio da leggereda easyMXP » dom 30 giu 2019, 00:04:43

Ma no, quasi nulla è fatto in casa.
Boeing e Airbus (o Fiat, Renault, Mercedes, ecc. in campo automobilistico, o ancora Airbus, Thales, ecc. in campo spazio, e così via) progettano il sistema e da lì preparano le specifiche dei sottosistemi, che poi sono praticamente tutti fatti all'esterno.
Perché? Perché ognuno sa fare bene solo poche cose, e a volte anche perché ci sono criteri di georeturn da rispettare.
Airbus è un caso un po' particolare, perché negli anni ha comprato tutto il comprabile in Europa e ha anche molte produzioni di componenti e sottosistemi, ma si tratta di sedi diverse e anche di società diverse, pur con lo stesso nome, per cui di fatto il rapporto tra Airbus "prime contractor" e Airbus "subcontractor" non è molto diverso da quello con una ditta esterna.

kco
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Re: Precipitato un B737 Max 8 di Ethiopian

Messaggio da leggereda kco » mar 02 lug 2019, 17:41:38

E siamo già oltre ottobre

https://www.flightglobal.com/news/artic ... f215182008


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Re: Precipitato un B737 Max 8 di Ethiopian

Messaggio da leggereda kco » sab 06 lug 2019, 17:28:28

Boeing has acknowledged the new issue on the Boeing 737 Max recently uncovered by the US Federal Aviation Administration (FAA), but gives no indication how long remedying it will take.

In his first comments since the FAA disclosed a data-processing problem that impaired pilots' trim recovery ability, Boeing chief executive Dennis Muilenberg said the airframer is of the view that "we must take action on this [issue], and we are already working on the required software".

Muilenberg remains tightlipped on when the beleaguered narrowbody will return to the skies, or if rectifying the issue could delay its return to service, simply saying: "It's important we take the time necessary to make these updates."

The Boeing chief's comments, which he posted on his Twitter account, came a week after the FAA discovered additional issues with the 737 Max. During simulator testing, FAA pilots found an issue that affected their ability to perform the procedure to counteract runway stabiliser trim. The issue was traced to a data-processing problem in the flight computer.

Muilenberg says that the "additional flight condition" must be addressed "to reduce pilot workload and ensure the safety of the airplane and the flying public."

"The families and loved ones of those on board have our deepest sympathies, and we hope this initial outreach can help bring them comfort" Dennis Muilenburg, chief executive, Boeing

Boeing has previously said that it will not present the 737 Max for FAA certification until it has "satisfied all requirements for certification and its safe return to service".

The company is in the midst of updating the 737 Max's Maneuvering Characteristics Augmentation System (MCAS).

Regulators worldwide grounded the 737 Max in March after the loss of an Ethiopian Airlines 737 Max 8, an incident which came five months after the October 2018 crash of a Lion Air 737-8.

The accidents, in which MCAS has been implicated as a contributory factor, killed a combined 346 people.

Boeing has now pledged $100 million as compensation for the families and communities affected by those two crashes, which equates to a little under $290,000 per person.

The airframer says the funds will provide living and education expenses for families, as well as community programmes and economic development in impacted communities.

"Boeing will partner with local governments and non-profit organisations to address these needs. This initial investment will be made over multiple years," says the manufacturer. More information will be released in "the near future", it adds.

"The families and loved ones of those on board have our deepest sympathies, and we hope this initial outreach can help bring them comfort," says Muilenburg.


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malpensante
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Precipitato un B737 Max 8 di Ethiopian

Messaggio da leggereda malpensante » sab 06 lug 2019, 18:17:30

Sempre più il MAX si dimostra versione raffazzonata per usare i motori nuovi disponibili sui NEO.
And Malpensa is going to be our Hub

easyMXP
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Re: Precipitato un B737 Max 8 di Ethiopian

Messaggio da leggereda easyMXP » sab 06 lug 2019, 19:05:27

Riagganciandomi ai post di belumosi nel thread IG, un intervento HW limitato (separare la disattivazione del MCAS dalla disattivazione del trim elettrico) basterebbe probabilmente a rendere nuovamente volabile il Max senza infilarsi in infinite analisi di failure del SW.
Non so quanto costerebbe modificare tutti gli aerei già costruiti, ma se Boeing dovesse risarcire tutti i danni alle compagnie con gli aerei a terra da mesi e ancora per una quantità imprevedibile di mesi a venire, contando anche quanto stanno costando lo sviluppo del SW modificato e i mancati ordini per il Max, forse sarebbe più conveniente.
Di sicuro darebbe un'immagine più seria di Boeing rispetto a quella di una compagnia di azzeccagarbugli più impegnata a trovare scappatoie per risparmiare che a fare un buon lavoro.

kco
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Re: Precipitato un B737 Max 8 di Ethiopian

Messaggio da leggereda kco » sab 06 lug 2019, 21:26:09

L' MCAS è un sistema ormai necessario per la sicurezza dell'aereo in quanto questo a bassa velocità tende a non avere un comportamento ideale in prossimità dello stallo. Questo problema di natura aerodinamica viene coperto con una pezza software quindi il Max non tornerà mai a volare senza un MCAS approvato e funzionante.
Sul poi disaccoppiare il trimmer elettrico dal MCAS magari è una questione solo software. Per ora però non ho mai letto che si stia andando in questa direzione. Vedremo.

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Re: Precipitato un B737 Max 8 di Ethiopian

Messaggio da leggereda kco » sab 06 lug 2019, 22:06:08

Southwest Airlines chief executive Gary Kelly expects the carrier's Boeing 737 Max fleet to remain grounded beyond 1 October, following new issues uncovered on the aircraft by US regulators.

The Dallas-based carrier had recently extended its 737 Max cancellations through 1 October, but Kelly told employees in an internal update that additional problems flagged by the US Federal Aviation Administration during simulator tests will result in a longer delay to its return to service.

"I'm sure that this will cause us to have to take the Max out of schedule beyond October 1," says Kelly in the update. He does not provide a timeline for its return to service.

"We'll also see what other modifications we might need to make to our plans for this year because it's obviously extending well beyond what I had hoped," Kelly adds.

Southwest operated the largest fleet of 737 Max aircraft prior to the global grounding, with 34 examples of the -8 variant in service.

The low-cost carrier had initially removed the 737 Max from its schedules through 5 August, before extending this to 2 September and now the start of October.

The latest change removes about 150 daily flights - or less than 4% - of the airline's peak-day schedule of more than 4,000 services

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kco
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Re: Precipitato un B737 Max 8 di Ethiopian

Messaggio da leggereda kco » lun 08 lug 2019, 08:19:09

Non mi aspetto di vedere molti switch ma uno è successo

https://www.flightglobal.com/news/artic ... f215411148

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Re: Precipitato un B737 Max 8 di Ethiopian

Messaggio da leggereda I-GABE » ven 12 lug 2019, 10:41:36

Intanto Willie Walsh dichiara che l'ordine dei Max e' stato spinto dall'insoddisfazione per la performance di Airbus (e.g. 70 giorni di ritardo sulla delivery).
https://www.bloomberg.com/news/articles/2019-07-11/airbus-delivery-delays-pushed-iag-ceo-walsh-to-order-boeing-max?srnd=premium-europe

Perche' ovviamente e' meglio ordinare un aeromobile per cui la data di ripresa dei voli e' incerta... :duro:
Alla fine sta negoziando con Airbus su tempi e prezzi, niente piu'.

Nell'articolo si cita anche che il program chief del 7737 Eric Lindblad lascia dopo un anno nel ruolo...

kco
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Re: Precipitato un B737 Max 8 di Ethiopian

Messaggio da leggereda kco » lun 15 lug 2019, 18:14:31

https://www.flightglobal.com/news/artic ... f215766855

Hanno cambiato il nome?

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I-GABE
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Re: Precipitato un B737 Max 8 di Ethiopian

Messaggio da leggereda I-GABE » lun 15 lug 2019, 18:55:03

L'articolo sembrerebbe indicare il contrario, ovveri che la denominazione 737-8200 fosse gia' in uso.

kco
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Re: Precipitato un B737 Max 8 di Ethiopian

Messaggio da leggereda kco » lun 22 lug 2019, 08:33:34

Da copia di flight international in mio possesso


Relatives of 737 Max crash victims want regulators to recertificate the Boeing narrowbody as a completely new aircraft, and only after investigations are complete.

That was one message delivered to US lawmakers on 17 July by relatives including Paul Njoroge, whose wife, three children and mother-in-law died in the March crash of Ethiopian Airlines flight 302.

The 737 Max is "too different from the original certified plane", Njoroge said in testimony to the House Transportation and Infrastructure Committee's aviation subcommittee. "Re-certification must take place in combination with a full legislative fix for the aviation safety system."

Investigations into the crash of the Ethiopian Airlines flight and Lion Air flight 610 are ongoing, but evidence indicates the jet's Maneuvering Characteristics Augmentation System (MCAS) automatically trimmed the aircraft into dives.

Boeing is co-ordinating with the Federal Aviation Administration (FAA) to certificate an updated version of the 737 Max's flight-control software.

Pilot training has also been identified as a possible factor in the two crashes. Njoroge criticises Boeing for shifting blame to "foreign pilot error" in the wake of the accidents, calling it "an insult". He argues that the airframer would never try to blame flightcrew actions if those fatal crashes had occurred in the US.

Committee chair Peter DeFazio describes as a "work in progress" its plans to have Boeing testify.

Separately, Boeing has dedicated $50 million of a previously announced $100 million to provide near-term financial assistance to families of people who died in the crashes.



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malpensante
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Re: Precipitato un B737 Max 8 di Ethiopian

Messaggio da leggereda malpensante » lun 22 lug 2019, 10:32:22

Mi chiedo se fra un anno volerà.
And Malpensa is going to be our Hub

kco
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Re: Precipitato un B737 Max 8 di Ethiopian

Messaggio da leggereda kco » mar 23 lug 2019, 18:06:01

Da copia di flight international in mio possesso


In an otherwise unremarkable first six months, concerns prompted by the Ethiopian Airlines Boeing 737 Max 8 fatal crash in early March 2019 have dominated the airline safety debate. That accident has generated industry-wide soul-searching, with calls for a re-examination of the way in which today's new aircraft designs are approved.

The Ethiopian fatal accident was the second of two unnervingly similar crashes within five months involving the same aircraft type. Both crash sequences were precipitated when a new automated control system operated in an unforeseen manner, according to the initial reports of the respective accident investigators. That this should happen twice in quick succession to new, latest-generation airliners has called into question the efficacy of long-established aircraft certification systems, at the very least as practised in Boeing's home country.

The doubts sparked by the Ethiopian and Lion Air crashes eventually led to the worldwide grounding of the type. The suspension of operations will continue until a technical fix and a crew training regime for the Max's aberrant Maneuvering Characteristics Augmentation System (MCAS) has been approved.

The predicted date for the type's earliest return to service is now October, but the US Federal Aviation Administration (FAA) has stated that this is not a certainty. The agency says it does not have a deadline, just an objective - to make the 737 Max series safe.

IATA director general Alexandre de Juniac voiced the industry's concern at the organisation's annual general meeting in June: "If you are in the shoes of the passengers or the general public, it is difficult to understand why there [was] a progressive grounding - why you have some authorities grounding [the 737 Max] immediately and others are waiting to make the same decision. This type of misalignment - and lack of collaboration and co-operation among regulators - I think it is probably the biggest threat on our safety/certification system."

CREDIBILITY THREAT

Certainly, there is a threat to its credibility, especially when the Max's lead certification authority - the FAA - was the last national agency to ground the aircraft it had certificated.

Meanwhile, flying goes on, and although the number of fatal airline accidents in January-June this year has increased compared with the same period in the two previous years, a caveat in last year's review also applies now: "This appearance of dramatic change is misleading, however. [Although] the number of fatal accidents only increased from six to eight [2017 and 2018 respectively], these totals are the two lowest in modern air transport history."

This year's total number of fatal airline accidents is 11, but that has still not reversed a gentle downward trend for the previous decade as a whole (see bar chart, below). And the number of fatalities for the two six-month periods has reduced from 323 in 2018 to 243 this year, mainly because the majority of the 2019 accidents so far have involved small commuter aircraft, or freighters with only the crew on board.

In some recent years there have been no fatal crashes involving jet airliners, but through the first six months of this year there were four (see accident listings): the Ethiopian 737 Max, an Aeroflot Sukhoi Superjet 100, a Saha Air 707 (operating a cargo charter for the Iranian air force) and an Amazon Prime 767 freighter. The remainder were turboprop- or piston-powered regional or short-haul types. Six of the fatal accidents involved passenger operations; the other five were cargo or other non-passenger services.

Among the non-fatal accidents, as usual the largest single event category was runway excursion, mostly on landing.

Every year there are a couple of crashes that, for lack of information, are really difficult to understand, even when a preliminary factual report has been released by the investigators who continue to probe the event. This year, the particularly puzzling accidents involved the Aeroflot Superjet in Russia and the Amazon Prime 767 freighter in the USA (see accident listings).

In the case of the Superjet, it clearly suffered a lightning strike, but the crew did not seem - at first - to have any problems dealing with the symptoms, which manifested as partial electrical failure. This affected various components, but not any primary controls.

However, as the aircraft returned to land, the crew seemed gradually to have less and less control over the aircraft, because their handling of the final approach was clumsy and the eventual landing was so hard that the aircraft caught fire. Only a thorough investigation of the aircraft's behaviour will reveal the nature of its apparent vulnerability to lightning damage - if indeed that is the whole story. The flightcrew survived the accident and their story of the experience will be important in determining what happened and why.

AMAZON FREIGHTER

The Amazon Prime 767 freighter began a normal descent towards Houston, the only problem for the crew being the avoidance of storm clouds, but air traffic control was helping them by providing vectors around these.

Although cleared to descend to 3,000ft, the aircraft, without any explanation, levelled at 6,000ft and even climbed slightly. Shortly thereafter, it was lost to radar. The freighter's power was advanced to maximum, it pitched up a little, but then began a significant nose-down pitching movement - directed by elevator deflection - until it reached 49° nose-down with wings level. Shortly before a high-speed impact with the ground the nose-down pitch was reduced to 20°.

The US National Transportation Safety Board says there was neither a stall warning nor stick-shaker in operation, and no communication during the final part of the descent. The event has an ominous feel about it.

Last year, one of the mystery accidents involved a 737-200 operating for Cubana that was observed to lose control completely soon after take-off from Havana, and plunge rapidly into the ground. Cuban investigators have since determined that inaccurate weight and balance information led to the aircraft taking off with the centre of gravity way outside limits, rendering it uncontrollable in flight (for fuller details see the section on recently published accident reports).

Amid the industry debate generated by the Max accidents, and referring to aircraft and equipment certification - especially in the light of the existing system of mutual recognition between manufacturing states - de Juniac wants to see consistency worldwide: "We have to be clear on what we think is needed, from the airline point of view, to manage safely the re-entry into service of the aircraft. What we say is we need strong collaboration between regulators, full transparency of the process and total alignment between regulators."

That sounds like a call for unification of certification regulation worldwide, which de Juniac must know will not happen in a world where nationalism is increasingly the new mood. But de Juniac adds: "If we are heading into a system where you have one certification process per country, that for us would be the worst possible outcome."

The FAA meets regularly with the other major certificating agency, the European Union Aviation Safety Agency (EASA), and the two work hard - with a fair degree of success - to achieve "harmonisation" of their rules and practices. But harmonisation is not the same as unification. The best de Juniac is likely to see is an opening up of the agencies to scrutiny by each other and ICAO.

What would they find if a cross-auditing practice became regularised? The FAA, as a part of its examination of the MCAS issues with the 737 Max, found another problem beyond the obvious factors seen to be at play in the Lion Air and Ethiopian accidents.

The problem discovered - believed to be a potential microprocessor failure revealed during simulator tests in late June - provided what the FAA described as "a potential source of uncommanded stabiliser motion". This would cause the stabiliser to pitch the aircraft nose down and recovery action by the pilots would take "seconds", observed the agency. The FAA was clearly signalling that a matter of seconds is too long, especially because the problem could occur close to the ground.

To understand the dilemmas the industry and its regulators face, it is important to record that Boeing is not uniquely vulnerable to faulty sensor data. FlightGlobal air transport editor David Kaminski-Morrow recently wrote a detailed study of cases affecting Airbus types when spurious air data, or faulty angle-of-attack vanes, caused serious incidents. In the case of one post-maintenance test flight near Perpigan, France in 2008, spurious angle-of-attack data was a causal factor in a fatal crash.

Kaminski-Morrow's study begins: "Airbus has not been immune to the consequences of spurious air data, and unexpected incidents illustrate the difficulties designers and regulators face in predicting and avoiding unintended aircraft behaviour… Airbus types have experienced serious issues which appear superficially similar to those affecting the Max. But some crucial considerations, centred on the Airbus design and time in service, have resulted in far less disruptive regulatory intervention."

SIGNIFICANT DIFFERENCES

There are differences from the Max case - for example, the simple fact that the Airbus systems take their angle-of-attack data from three vanes instead of one or two, and employ a "voting" system. Since no system is perfect, occasionally two faulty vanes can give the same wrong reading and outvote the correct one. Mathematically, however, the chances of a faulty angle-of-attack vane compromising safety are very low, and the small number of such cases over a long in-service period testifies to that.

Airbus's airworthiness authority, EASA, has not been idle in the face of these occurrences, and perhaps the FAA, at a time like this, could usefully study its approach regarding sensors. Kaminski-Morrow writes: "EASA describes the high-incidence protection system on the A320 and A330 families as 'robust', noting the inclusion of three angle-of-attack sensors, compared with two on the 737 Max, normally enabling voting logic to eliminate a single erroneous reading. [EASA] adds that the Airbus [now] has 'enhanced' monitoring and surveillance of the sensors."

Reflecting on the many potential lessons from the Max accidents, the UK Flight Safety Committee had these observations to make in a recent issue of its Focus magazine, particularly considering how far the 737 series has been developed since its entry into service in 1967: "Is it right that an aircraft with a new fuselage, new wings and different engines is treated as if it is simply an upgrade of the original platform?

"Compared with earlier versions, the stall characteristics that required installation of MCAS on the 737 Max will have been affected by changes in the planform and positioning of the engines. When do such changes become sufficiently significant to require certification to start from scratch? How much stretch or increase in wing area or increase in power is too much where grandfather rights are concerned? And how far can you reduce seat pitch before the evacuation demonstration carried out years before on a different size of aircraft becomes invalid?"

The article aims the same questions at crew instruction, specifically the "differences training" that enables a pilot type rated on, say, the 737NG series to qualify for the Max series with zero simulator time, and just 4h of computer-based training on a tablet. And the practice of truncating type rating training within a series, or even within a manufacturer's entire fleet, is not limited to the 737 series.

It is a good thing that the FAA has not set itself a specific deadline for returning the 737 Max to service, because it has important decisions to make. The world - not just the USA - will be watching closely.

Inviato dal mio WAS-LX1A utilizzando Tapatalk

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malpensante
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Re: Precipitato un B737 Max 8 di Ethiopian

Messaggio da leggereda malpensante » mar 23 lug 2019, 18:18:29

C'è stata troppa superficialità da parte di Boeing e di FAA e adesso non ci sono idee per rimediare all'evidente insufficienza dell'attività di sorveglianza nella certificazione.
And Malpensa is going to be our Hub

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wrth
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Iscritto il: sab 07 giu 2008, 12:56:19
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Re: Precipitato un B737 Max 8 di Ethiopian

Messaggio da leggereda wrth » mer 24 lug 2019, 08:06:21

Certo che gli ultimi due progetti commerciali (787 e MAX) qualche grattacapo l'hanno creato a Boeing e soprattutto non si vede la fine del calvario per il MAX.


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